Question:

Perhaps I can help.  I work with RV solar panel output power living area electrical a lot.  Check your Dodge owner’s manual for alternator amperage rating.  It is probably about 80 amps. Almost any rating, 30 to 100 will provide enough electricity to run most of the DC appliances in your RV … if a) the engine is turning at least 1000 rpm.  In most cases, this is fast idle or better. and b) you have adequately sized wire between the alternator and the trailer.  Most harnesses do not.  To send 30 amps to the trailer, you need at least 10 gauge wire.  It should go from near your truck alternator to the trailer battery. Even at 30 amps, a single depleted marine – type deep cycle battery will require three hours or more to re – charge. – Hide quoted text — Show quoted text – I just had an experience with this. I am rather new at RVing and I thought I was told that all I had to do to recharge my batteries was to hook up the truck’s trailer connections and I could charge and/or run the 12 volt system by running the engine. So we ran out of battery and I hook up the truck and although it appeared to be charging it was awfully slow. Secondly it did not power the system and I could not run the furnace to take the chiil off. When I got home I asked about the lack of strong charge or ability to run the 12 volt system with the engine running. I was told I had misunderstood and that the battery connection from the  truck alternator via the trailer wire harness would apply only a light trickle charge and I would have to run the engine for hours to get the batteries back up. Lastly the charge coming in would not be enough to run the 12 volt system of the trailer. I have a 1997 Wanderer 27 ft 5th wheel and a Ram  Deisel with two batteries. Am I missing something here? I would expect it to work better then that.  Maybe at Idle you will have low current for changing but it should still be 14V. but I will have to check that.  I have a Dodge also and will have to test “how much current” can be supported by the Truck connector,  I would at least expect 20 amp which should run your heater.   I have 2-13″ batteries in the camper and have not needed to recharge with my truck. But I always “thought” I could.  Sounds like a project for this weekend. Will Rosenberry Will Rosenberry Remove “Nospam” to email

Response:

I have a 27 ft. fifth wheel solar panel output power and would like to do more dry camping.  I was thinking of buying a portable generator of around 4,000 watts, but was advised against it by this group if my only use was for the AC in hot weather. I just got back from a a trip and noticed that one fifth wheel owner had a Coleman 1750 Pulse which he was using to recharge his batteries.  This is what I would like to do–have a generator handy to charge the batteries.  Any suggestions? Bob Shimane, San Jose, CA I’m gathering parts to build a charger using a 5 hp lawnmower engine and an 80 ampere car alternator, with a charge controller.  With a good muffler, it should be more economical to operate for battery charging than running the mh engine, a 6.5kw generator to the mh converter, a 6.5kw generator to the mh inverter’s 50 amp charger, or a Coleman generator with a 12 volt charging circuit. Gail – in the Great Pacific Northwest

Even with a good muffler it will be noisy. There is a lot of sound radiating off the fins of the head, from gear and lifter slop etc. Your idea should work just fine, but don’t expect quiet. Erich

Response:

Your tow vehicle can produce far solar panel output power more current for charging your batteries then any Generator you would want to afford.

I’ve found that this is not true in my case.  We have a 34′MH with an Onan 6.5k genset.  We get more charge to the two BIG true deep cycle batteries than we do thru the alternator.  Neither method will fully charge the batterys in a short time however.  Plus it has a noise level far lower then any generator I have ever heard True, but we’re looking into one of those muffler systems that supposedly reduces the genset noise down to 5db.  Anyone have any experience with these? – Hide quoted text — Show quoted text – I just had an experience with this. I am rather new at RVing and I thought I was told that all I had to do to recharge my batteries was to hook up the truck’s trailer connections and I could charge and/or run the 12 volt system by running the engine. So we ran out of battery and I hook up the truck and although it appeared to be charging it was awfully slow. Secondly it did not power the system and I could not run the furnace to take the chiil off. When I got home I asked about the lack of strong charge or ability to run the 12 volt system with the engine running. I was told I had misunderstood and that the battery connection from the  truck alternator via the trailer wire harness would apply only a light trickle charge and I would have to run the engine for hours to get the batteries back up. Lastly the charge coming in would not be enough to run the 12 volt system of the trailer. I have a 1997 Wanderer 27 ft 5th wheel and a Ram  Deisel with two batteries. Am I missing something here?

Prior to a trip, we plug solar panel output power our MH into shore power for 24 hours.  We fire up the fridge with LP and let the AC charge the deep cycle batterys.  While camping, we run the genset for about 30 minutes in the morning (after 7:00 am) while making coffee, and again for about 30 – 45 minutes in the evening (before 9:00 pm) when preparing dinner.  We are conservative with the TV and we’ve lasted a week with this method without running down the batterys.  We might have been able to go longer but didn’t have the time. Anyway, we again hook up to shore power for 24 hours when we get home.  Believe that this is one of the most important parts of maintaing the deep cycle batterys.  Then, it’s back to storage until the next trip. Mike, CA

Response:

Plus it has a noise level far solar panel output power lower then any generator I have ever heard True, but we’re looking into one of those muffler systems that supposedly reduces the genset noise down to 5db.  Anyone have any experience with these?

[disclaimer: no direct experience. just thinking out loud...] Even if you reduced the exhaust noise to 0db I have been lead to believe that the mechanical noises from most generators is still quite loud (at least more than you think.) OTOH it might help. Eric — Eric A. Roellig

Response:

Boy have we come a long way from campingsolar panel output power. Now we take our homes with us and need A/C and TV. Hey, don’t forget the microwave. and the Satellite dish!  what would Camping be without the Sat TV! But I can use the dish in mine when I am “roughing it”!  I have a DC-AC inverter!

Yeah, there is nothing better after a hard day of dirt bike riding, to take a shower in the motorhome, crank up the sattelite dish and spend the evening watching SpeedVision! Or an old copy of On any Sunday in the VCR. Erich  ”roughing it is for the young”

Response:

So . . . . . . what’s yer definition of “camping?”  Using an RV solar panel output power?  A tent?   I say, “camping” is whatever you make it.  Just get out there and enjoy the outdoors, regardless of how you do it.  Whether it’s in a tent fly, a custom motorcoach, or anything in between.

Response:

Yeah, there is nothing better solar panel output power after a hard day of dirt bike riding, to take a shower in the motorhome, crank up the sattelite dish and spend the evening watching SpeedVision! Or an old copy of On any Sunday in the VCR. Erich  ”roughing it is for the young”

Your right!  I even carry my KTM 300 EXC on the back of the 5th wheeler! Will Rosenberry Brandywine Enduro Riders Remove “Nospam” to email

Response:

The Coleman 1750 is a nice little generator but it is noisier than gensets designed for RVs and solar panel output power may well be underpowered for running your A/C. Remember the 1750 Watts refers to the max the unit will put out for a short period of time. I believe that it is rated closer to 1300 watts for continuous use. Check your A/C specs to see if that will work. (And if it’s close, be sure to check the specs of the genset you buy–my memory has been known to be faulty. <gr). That being said, we used one for a season and a half for morning coffee, emergency battery charging(using an automotive charger), and occaisional running of a lower power A/C unit. And lest this turn into a noise/courtesy thread, we were always quite isolated or in an already noisy environment(rest area right nest to highway).

Response:

I’m gathering parts solar panel output power to build a charger using a 5 hp lawnmower engine and an 80 ampere car alternator, with a charge controller.  With a good muffler, it should be more economical to operate for battery charging than running the mh engine, a 6.5kw generator to the mh converter, a 6.5kw generator to the mh inverter’s 50 amp charger, or a Coleman generator with a 12 volt charging circuit. Gail – in the Great Pacific Northwest

Response:

Tents, pop-ups, and all the others. Been there done that, loved it. To old to sleep on the ground, work my fanny off all day just to camp, no thank you. Us old guys have already done that. Does anyone know where I can get a T.V guide ? Dan

Response:

I just had an experience with this. I am rather new at RVing and I thought I was told that all I had to do to recharge my batteries was to hook up the truck’s trailer connections and I could charge and/or run the 12 volt system by running the engine. So we ran out of battery and I hook up the truck and although it appeared to be charging it was awfully slow. Secondly it did not power the system and I could not run the furnace to take the chiil off. When I got home I asked about the lack of strong charge or ability to run the 12 volt system with the engine running. I was told I had misunderstood and that the battery connection from the  truck alternator via the trailer wire harness would apply only a light trickle charge and I would have to run the engine for hours to get the batteries back up. Lastly the charge coming in would not be enough to run the 12 volt system of the trailer. I have a 1997 Wanderer 27 ft 5th wheel and a Ram  Deisel with two batteries. Am I missing something here?

I would expect it to work better solar panel output power then that.  Maybe at Idle you will have low current for changing but it should still be 14V. but I will have to check that.  I have a Dodge also and will have to test “how much current” can be supported by the Truck connector,  I would at least expect 20 amp which should run your heater.   I have 2-13″ batteries in the camper and have not needed to recharge with my truck. But I always “thought” I could.  Sounds like a project for this weekend.

Response:

Depends more on the charger than solar panel output power the generator capacity.  Many chargers don’t put out all that much, and it can take a long time to recharge the batteries off of a 10-15 amp charger (and many of the el-cheapo chargers are over-rated).   If you have a good charger that will put out 20 amps or more, or a good converter, then it’s probably worth it.  If your converter only puts out 2-5 amps it’s probably a waste of time (you can get more from a solar panel). — www.windsun.com Over 10,000 items for solar & renewable energy -

Response:

In the annals of history it is solar panel output power recorded that on Thu, 28 May 1998 00:17:05 GMT it was hitman who stated to rec.outdoors.rv-travel: : Boy have we come a long way from camping. Now we take our homes with us and need : A/C and TV. I resemble that remark. 8^) — Protected with spamgard(tm). Include the word “rabbit” in your subject line.

Response:

Your tow vehicle can produce far more current for charging your batteries then any Generator you would want to afford.  Plus it has a noise level far lower then any generator I have ever heard.  Most 7 pin wire trailer connectors are wired for 12V charge (or can be wired)

I just had an experience with this. I am rather new at RVing and I thought I was told that all I had to do to recharge my batteries was to hook up the truck’s trailer connections and I could charge and/or run the 12 volt system by running the engine. So we ran out of battery and I hook up the truck and although it appeared to be charging it was awfully slow. Secondly it did not power the system and I could not run the furnace to take the chiil off. When I got home I asked about the lack of strong charge or ability to run the 12 volt system with the engine running. I was told I had misunderstood and that the battery connection from the  truck alternator via the trailer wire harness would apply only a light trickle charge and I would have to run the engine for hours to get the batteries back up. Lastly the charge coming in would not be enough to run the 12 volt system of the trailer. I have a 1997 Wanderer 27 ft 5th wheel and a Ram  Deisel with two batteries. Am I missing something here?

Response:

EXCELLENT responses guys! I am sure most of us have paid our dues in sleeping bags, and under tarps – but the LAST thing *I* need in my “golden years”, is someone ELSE preaching to me about “real” camping (their version)… -

Response:

a Coleman 1750 Pulse which he was using to recharge his batteries.  This is what I would like to do–have a generator handy to charge the batteries.

Whichever generator you end up with, make sure it has a certified spark arrester muffler, or you won’t be able to use the generator in certain areas.   On certain Colemans, it’s apparently an option.

Response:

Go for it   I have a Coleman solar panel output power 1850 Powermate  and its used to charge batteries  and to run small goodies in the trailer    since I only dry camp   and the closest other camper is miles away  I don’t worry about noise  the unit is not real noisy anyway   It also has a built in  charger 15 Amp  cost is 399.00 at Costco.

Response:

I’ve probably missed something, solar panel output power and from your comments I fear it might have been a politically correct discussion about generators and campground noise. Let’s assume for a moment that you’re camped alone in the middle of nowhere. Thus conveniently ignoring the morality of the situation, a properly sized generator works great for running an air conditioner. Moreover, if you come back to a hot trailer after leaving it closed up all day in the hot sun a few minutes of A/C can make a world of difference. You can indeed charge your batteries with a generator, but it’s going to have to run for a long time. We’ve been cornered into doing this a few times while dry camping during the winter. It’s a last resort, but very welcome when it’s needed.     If you are truly wanting just to recharge batteries, I have two words for you: solar panels. They work quietly all day long and will keep your batteries charged right up to the top. Based on our experience, 6 amps. of output will solve most of your three-season camping needs. The problem gets a little more difficult during the winter because they days are shorter, cloud cover is more prevalent and your electrical demands will be greater (e.g., furnace blower motor). I’m not sure it’s really practical to run an air conditioner through an inverter, but it’s theoretically possible (the air conditioner in your trailer probably draws about 1200 watts, and that’s a load of over 100 amps. on your batteries). If you do run an air conditioner through an inverter you will definitely need more solar panel output to recover.

Response:

Hi, Our Amateur Radio group has a GenRac, and it’s a marvelous machine. We have a 4K model, and it meets all out needs and then some. It’s easy to maintain, and starts very easily. We use it in constant use, and it runs quite a long time on a tank of gas. It’s not lightweight, but seems to be very reliable, and relatively quiet (but not even close to a Honda), probably the quietest we could have gotten for our needs. Hope this helps….          Ed, Tempe, AZ -

Response:

Guess what?  They are ALL outrageous! Al – Hide quoted text — Show quoted text – I have heard the replace cost of parts for the genrac are outrages. There have been several posts lately on GenRac generators. Has anyone had a bad experience with one ? I am curious about reliability and repairability, ease of starting, etc. Are there any brands which have caused people headaches??? I am not referring to noise, but rather operation.

Response:

I have heard the replace cost of parts for the genrac are outrages.

Response:

Your experience with the Generac parallels that of others I have known.  Thanks for the input. Have one correction for your calculations – The 30 amp was on the money but the “fifty amp” connection is actually a 230 volt connection capable of 50 amps.  In most applications, the two legs of the 230 are split giving two 115 volt legs at 50 amps each.  The actual power requirement is 11,500 amps – but I have yet to see anyone that actually uses anywhere near that amount of power.  While I have a “fifty amp” shore power for our coach, I rely on an 8KW diesel generator and I don’t think it has ever been fully loaded.  At some rallies I have even had others plugged into my rig for power. George – Hide quoted text — Show quoted text – Hi all,    The other day I recommended a generator at Sam’s and got the name brand wrong.  The Brand Name is Coleman, 3500 advantage.  This is a good 30 amp generator. On GenRac generators :   I owned three.  Each had reliability problems. The first, was a real gem!!! ;~((   After less than 100 hrs. of operation the heat shroud literally fell off.  I believe they over torqued the bolts holding it on since every bolt hole on the shroud failed.  Under the bolts I found a piece the shroud with the holes.  The next item to fail in similar fashion was the starter mechanism failed in exactly the same way.  I returned it to the store where I bought it under warranty and they replaced it with a like item.  Being on a hunting trip, and needing the generator I accepted their offer.  The second one lasted less than 24 hours when the clutch mechanism of the pull starter failed completely.  In addition I found numerous bolts loose.  I returned this one to the store.  When I did, I was instructed to take it around to the loading dock.  The on the dock were 12 more awaiting shipment to the manufacturer including the first one, all looked to have failed in similar fashion in that parts were taped to the frame.  They replaced the item with another of the same brand.  Not having my receipt, I took their offer.  The price had lowered by $200.00 and I could not see loosing $200.00.  The third one finished out the trip.  But after all this, I decided not to put my faith in the third generator and returned it to the local store and receive a complete refund.    Now this is just one mans problems, but I think that after seeing a dozen being returned to the manufacturer, that either the design was faulty, or their quality control department definitely needs some new personnel.    Most of the generators found in discount stores feature lawn mower engines as others have said.  Briggs and Stratton engines work fine under the light load of a lawn mower, but when it comes to a 4000 Watt generator something much stronger is necessary.  Just raising the horse power does not due.  If the parts in the engine are not upgraded as well.  A 10 house lawn mower used to cut grass will probably out live me, but take that same engine and connect it to a 4000 Watt generator, and you will be lucky to get more than 2 or three years of use. Now for some math, which might help you select the proper generator for your RV.  I have seem RV’s and trailers with both 30 amp and 50 amp requirements. As a basic rule of thumb(discounting load factors) a 30 Amp would require 30 amps X 125 volts, or 3650 watts.  A 4000 Watt continuos power generator which provides a 30 amp outlet should do very well.  It should be rated to withstand at least a 20% overload of short duration.  A 50 amp RV would require a 50 amps X 125 volts or 6250 Watts.  Again a 7000 Watt generator with a 20% surge overload should due nicely. The problem is not the generators themselves but the engines connected to them.  Now I know there have to be some good mechanics and engineers on line who could help in this relation.  Since the above generators would surfice, how about you with the mechanical knowledge tell us what we should look for besides horse power, and OVH engines, like some specifications on duty ratings,  wall thickness,  one or two cylinders and the like.  TIA Sincerely Buck There have been several posts lately on GenRac generators. Has anyone had a bad experience with one ? I am curious about reliability and repairability, ease of starting, etc. Are there any brands which have caused people headaches??? I am not referring to noise, but rather operation.

Response:

Hi all,     The other day I recommended a generator at Sam’s and got the name brand wrong.  The Brand Name is Coleman, 3500 advantage.  This is a good 30 amp generator.  On GenRac generators :   I owned three.  Each had reliability problems. The first, was a real gem!!! ;~((   After less than 100 hrs. of operation the heat shroud literally fell off.  I believe they over torqued the bolts holding it on since every bolt hole on the shroud failed.  Under the bolts I found a piece the shroud with the holes.  The next item to fail in similar fashion was the starter mechanism failed in exactly the same way.  I returned it to the store where I bought it under warranty and they replaced it with a like item.  Being on a hunting trip, and needing the generator I accepted their offer.  The second one lasted less than 24 hours when the clutch mechanism of the pull starter failed completely.  In addition I found numerous bolts loose.  I returned this one to the store.  When I did, I was instructed to take it around to the loading dock.  The on the dock were 12 more awaiting shipment to the manufacturer including the first one, all looked to have failed in similar fashion in that parts were taped to the frame.  They replaced the item with another of the same brand.  Not having my receipt, I took their offer.  The price had lowered by $200.00 and I could not see loosing $200.00.  The third one finished out the trip.  But after all this, I decided not to put my faith in the third generator and returned it to the local store and receive a complete refund.     Now this is just one mans problems, but I think that after seeing a dozen being returned to the manufacturer, that either the design was faulty, or their quality control department definitely needs some new personnel.     Most of the generators found in discount stores feature lawn mower engines as others have said.  Briggs and Stratton engines work fine under the light load of a lawn mower, but when it comes to a 4000 Watt generator something much stronger is necessary.  Just raising the horse power does not due.  If the parts in the engine are not upgraded as well.  A 10 house lawn mower used to cut grass will probably out live me, but take that same engine and connect it to a 4000 Watt generator, and you will be lucky to get more than 2 or three years of use. Now for some math, which might help you select the proper generator for your RV.  I have seem RV’s and trailers with both 30 amp and 50 amp requirements. As a basic rule of thumb(discounting load factors) a 30 Amp would require 30 amps X 125 volts, or 3650 watts.  A 4000 Watt continuos power generator which provides a 30 amp outlet should do very well.  It should be rated to withstand at least a 20% overload of short duration.  A 50 amp RV would require a 50 amps X 125 volts or 6250 Watts.  Again a 7000 Watt generator with a 20% surge overload should due nicely. The problem is not the generators themselves but the engines connected to them.  Now I know there have to be some good mechanics and engineers on line who could help in this relation.  Since the above generators would surfice, how about you with the mechanical knowledge tell us what we should look for besides horse power, and OVH engines, like some specifications on duty ratings,  wall thickness,  one or two cylinders and the like.  TIA Sincerely Buck -

Response:

Yes,  and Generac solar panel output power does or at least used to make a RV model.  Everyone that I have known that had a Generac whether Rv or other, has had many reliability problems with them.  Granted, I have not owned one, I tried to learn from the mistakes of others. WRICO, Kohler, and Onan seem to have the best generators for our type of usage. George – Hide quoted text — Show quoted text – There have been several posts lately on GenRac generators. Has anyone had a bad experience with one ? I am curious about reliability and repairability, ease of starting, etc. Are there any brands which have caused people headaches??? I am not referring to noise, but rather operation.

Response:

Gererac sells three different qualities of generators for consumer use.  The cheapest using a lawn mower type motor which sells for about $500 for a 5000 watt unit.  The second (XL) uses an OHV motor and sells for about $650 for a 4500 watt unit.  The third is what they call a commercial version and sells for about $800 for a 4500 watt unit.   The commercial version uses the same motor that the XL line uses but have things like an oil filter and some other stuff.  I had a pamphlet that I picked up at Home Depot telling about the different lines before I bought mine.

Response:

There have been several posts lately on GenRac generators. Has anyone had a bad experience with one ? I am curious about reliability and repairability, ease of starting, etc. Are there any brands which have caused people headaches??? I am not referring to noise, but rather operation.

Response:

There have been several  solar panel output powerposts lately on GenRac generators. Has anyone had a bad experience with one ? I am curious about reliability and repairability, ease of starting, etc.

This is the easiest pull start motor I have ever had.  You don’t even need to rip the cord hard.  Just pull it slow and it will still start! Are there any brands which have caused people headaches???

It even comes with a tune up kit -

Question:

Actually, the relay solar panel output ratings will eventually die of old age, and before that time, the contacts can become so resistive that you have a significant voltage drop at high charge currents.

All things made by man – including the pyramids – decay with time. I do not deny that a relay CAN croak, or that the contacts CAN become resistive.  What my experience tells me, though, is that 6 diodes will go belly up before one decent relay goes away. I make no pretense of statistical proof – I only say I NEVER had good success with diode isolators, and never had a problem with relays.   Your experience may be different. Will KD3XR

Response:

Will Well, it’s about time.  We finally disagree on something.  I have never had a problem with a diode isolator and did have a relay die in the closed position.  Fortunitly the fuse prevented any problems. solar panel output ratings.

Response:

Well, it’s about time.  We finally disagree on something.  I have never had a problem with a diode isolator and did have a relay die in the closed position.  Fortunitly the fuse prevented any problems.

you take somebody as disagreeable as I am solar panel output ratings and it was bound to happen! I suppose neither of us have enough data to make a case one way or the other. When you look close at the problem an isolator is important only in rare instances. Most people are careful not to run their batteries flat anyway. Being a fan of the KISS principle and never having suffered a relay failure in this application, I’m using a relay in the rig I’m building up now, but a properly designed diode array can certainly do the job.

Response:

I connect a clip lead from solar panel output ratings the house battery + to the engine battery + on my HR motorhome and let the inverter-charger (Heart 1000-watt unit) keep them all topped off. The rig is kept plugged in at the house at all times. I then remove the clip lead when I am ready to take the rig out. In my rig, there is a relay that makes that connection at all times that the engine is running so that the alternator can be charging the house batteries while underway. I have never seen the need for an isolation diode in this application since there is little liklihood of the engine battery attaining a higher terminal voltage than the house batteries (already under trickle charge at least by the inverter or converter) and thus losing charge to them.

Response:

It’s not exactly clear what solar panel output ratings was meant by “converter” in the original post.  Don’t solar systems already have series diodes?  Add another diode to the starting battery.  Depends on your solar controller. My AC converter/charger has a relay that engages when you apply AC. I haven’t checked whether there are extra contacts, but an additional relay could be added to connect the starting battery.  I’d use some sort of current limit, like a light bulb in series. Another simpler thing you might do is to put a light bulb between the positives of batteries.  Use a couple of the biggest tail light bulbs you can find in parallel.  This will do a good job of keeping unloaded systems trickle charged.  If you try to start the engine, the lamps light, but little current flows.  While you’re discharging the RV battery, there’s little difference between it and the engine battery, so little current flows out of the starting battery thru the light bulbs.  If your loads are high current and you recharge frequently, starting will not be affected.  This won’t work for long-term low-current loads. It’s pretty easy to calculate the relative drains for the two batteries to see if you’re in trouble. Of course, you can fix it all with a few FETs. address.

Response:

In my rig, there is a relay solar panel output ratings that makes that connection at all times that the engine is running so that the alternator can be charging the house batteries while underway. I have never seen the need for an isolation diode in this application . . .

You are correct, IMO, because the relay takes the place of the traditional isolation diode and does a better job because there is virtually no voltage drop across it. Will KD3XR

Response:

Actually, the relay will solar panel output ratings eventually die of old age, and before that time, the contacts can become so resistive that you have a significant voltage drop at high charge currents. Since coach batteries are often discharged to 50% or less, and the starting battery to 80%, there will be an imbalance in the charging ability of the alternator. Although a diode isolator assembly will have a voltage drop across the diodes, the alternator voltage sense terminal is connected to the start battery side, and the alternator has plenty of voltage compliance to make up this drop. Unfortunately, the converter does not have this voltage compliance, so it cannot be used to charge the starting battery through any diode or device using them. However, it would not be difficult to modify the convertor design to have an additional rectified output to use in charging the starting battery. I’ve always wondered why they don’t (other than being too cheap!).

Response:

. .  If you simply run a small solar panel output ratings wire from each positive post to tie them into a parrallel bank with a common ground you will have access to the capacity of all three batteries on all loads placed upon them. <snip  Whenever you start your engine you will be trying to draw starter amperage, or at least a fair portion of it, thru the wires connecting each of the batteries to the others.

I think we should make sure everyone understands that a “small wire” is incompatible with starter amperage, for the very reason you mention.  You mentioned an isolator circuit and that’s fine, but someone could easily set their coach on fire using a small wire that was NOT disconnected when trying to start.

Response:

| Anything wrong with solar panel output ratings connecting the positives of the coach batteries with | the engine battery (they’re all 3 together), so the converter and solar | charger will charge the engine battery also?   The reason it wasn’t done this way from the factory is that when the coach and engine batteries are wired in parallel, they will all run out of juice at the same time.  So if you accidentally leave a light while in storage, by the time you get back to the unit all three batteries will be dead and you’ll have no quick way to start the RV. Worse yet, if you run the furnace over several nights while boondocking, you could be stuck in the boondocks with three dead batteries.  But you could wire up a relay that connects the positives only when connected to shore power.  Making the relay energize when the solar panel output exceeds appliance drain would be more of a trick. CAUTION: just because you have three batteries in the same compartment doesn’t mean they’re all 12 volts!  There is a definite possibility that you have one 12 volt engine battery and two 6 volt coach batteries.   Wiring all the positives together in this case would create some fireworks.  To get the charging you want in this case you’d only wire to the positive of the “high” 6-volt, i.e. the battery whose negative terminal is NOT connected to the chassis ground but to the positive of the other 6-volt battery. Anyway, in case I haven’t made myself clear, I don’t think this is a good idea.  If your engine battery isn’t holding a charge, get a new engine battery and/or hunt down whatever parasitic load is draining it.

Response:

A lot of motorhomes have an solar panel output ratings isolation diode pack that prevents flow from the coach to the chassis battery to prevent the discharge of the chassis battery.  Camping World has a unit called “Keep It Up” that bridges across the isolation diodes that do just what you are after.  It keeps your chassis battery charged while you are plugged into shore power.  There are 2 “Keep It Up” units.  Get the more expensive one as it does a better job.  I have been using it for several years and it works great!

Response:

Anything wrong with connecting the positives of the coach batteries with the engine battery (they’re all 3 together), so the converter and solar charger will charge the engine battery also?  I plug it up to the house for about a day every couple of weeks.

Response:

Anything wrong with connecting the positives of the coach batteries with the engine battery (they’re all 3 together), so solar panel output ratings the converter and solar charger will charge the engine battery also?  I plug it up to the house for about a day every couple of weeks.

most coverters (and all but the bigger solar arrays) provide a pretty small charging current. If just want to keep ‘em up, fine – but I would not plan on getting ‘em charged up from a depleted condition.

Response:

Jim Hooking all of the batteries together, depending on how you do it, will work fine.  If you simply run a small wire from each positive post to tie them into a parrallel bank with a common ground you will have access to the capacity of all three batteries solar panel output ratings on all loads placed upon them. Therefore, if you run the batteries down using lights in the couch your starting battery is also dead.  Whenever you start your engine you will be trying to draw starter amperage, or at least a fair portion of it, thru the wires connecting each of the batteries to the others.  Both positive and negitive sides. You might want to consider using some isolation techniques in this system to prevent inconvieniance or damage.

Question:

solar panel output voltage Is there such a thing as a good solar-powered anchor light? snip It’s too risky operating the anchor light on the ship’s main battery, since it tends to run the battery down quickly.  Self- contained battery operated anchor lights, like those made by Guest and ACR, work OK but the 6 volt batteries need to be changed too often.  Isn’t there a better way?   Some members of the club have tried using solar-powered sidewalk lights like you find in a hardware or garden store. While they are low-maintenance, they are also not very bright. snip   Does anyone have any bright ideas along this line?solar panel output voltage

Bill, I’ll just start with one question; How much do you want to spend? Obviously solar powered lights do work. We see them all the time on navigational buoys.  Perhaps you have also seen the large solar panels and batteries required to keep them running? While I’ve never designed a solar rechargable system, the numbers involved probably go something like this for a minimal (read marginal) system: To meet the USCG 2 mile visibility requirement would require a 10 watt bulb and lens (about $50+ for marine quality).  That’s about 1 amp for each of about 10 hours of night on the Hudson in the summer (10 amp hours from a 12 volt system).solar panel output voltage   If you want to have enough battery reserve to keep the light on for four nights when the sun is overcast all day you will need a minimum of 40 amp hours of battery (4 x 10 amp hours).  That would be a small car battery (about $50).  To recharge the battery would require solar cells rated at 20 watts minimum to make up for inefficiencies in the battery, the sun angle to the panel and times when the sky is overcast.  Solar panels of this capacity start at $250.  To keep the system from overcharging would require a regulator ($50) and to turn the light on and off at dusk would require a sensor (I’m guessing here $50). Total cost for minimal system?  $450.  That’s a lot of 6V cells. For a ride or two this summer,solar panel output voltage

Response:

require solar cells rated at 20 watts minimum to make up for inefficiencies in the battery, the sun angle to the panel and times when the sky is overcast.  Solar panels of this capacity start at $250.solar panel output voltage  To keep the system from overcharging would require a regulator ($50) and to turn the light on and off at dusk would require a sensor (I’m guessing here $50). Total cost for minimal system?  $450.  That’s a lot of 6V cells.

On the other hand, a solar panel of that capacity would probably provide most of the 12v power the boat needed anyway so why not just buy the panel and use it to charge the main battery bank?solar panel output voltage  Then turn on the anchor light and go to sleep at night. As far as regulators go, we never bothered with one for either the solar panels or the wind generator. Simply watch the battery voltage with a digital voltmeter and either put on a load or turn off the charging when the voltage reaches about 15 vdc.     solar panel output voltage

Response:

Is there such a thing as a good solar-powered anchor light?   I belong to a yacht club located on the Hudson River, where river traffic really demands that boats on moorings be lighted.solar panel output voltage  But keeping an anchor light on a boat on a mooring is a problem. It’s too risky operating the anchor light on the ship’s main battery, since it tends to run the battery down quickly.  Self- contained battery operated anchor lights, like those made by Guest and ACR, work OK but the 6 volt batteries need to be changed too often.  Isn’t there a better way?   Some members of the club have tried using solar-powered sidewalk lights like you find in a hardware or garden store.solar panel output voltage  While they are low-maintenance, they are also not very bright. I suppose they don’t stay lit all night long either, so there is room for improvement with this idea. solar panel output voltage    Does anyone have any bright ideas along this line? Bill Spencer (Hyde Park NY)

Response:

-solar panel output voltage   Is there such a thing as a good solar-powered anchor light?  I belong to a yacht club located on the Hudson River, where river traffic really demands that boats on moorings be lighted. But keeping an anchor light on a boat on a mooring is a problem. It’s too risky operating the anchor light on the ship’s main battery, since it tends to run the battery down quickly.  Self- contained battery operated anchor lights, like those made by Guest and ACR, work OK but the 6 volt batteries need to be changed too often.  Isn’t there a better way?  Some members of the club have tried using solar-powered sidewalk lights like you find in a hardware or garden store. While they are low-maintenance, they are also not very bright. I suppose they don’t stay lit all night long either, so there is room for improvement with this idea.  Does anyone have any bright ideas along this line?

Response:

Is there such a thing as a good solar-powered anchor light? (snip) Bill Spencer (Hyde Park NY)

I would put a good solar charger on my main battery system, and run the lights off of the main battery system.  That way you don’t have to mess with the additional lights.  Good solar chargers can be expensive, and you may have to add more if they can’t keep up with the constant drain.solar panel output voltage   I’ve used one for a year now and it seems to work well, but I have not run my anchor lights for more than 10 nights in a row. Then there is always an oil lamp, but you have to refill it. solar panel output voltage

Response:

Is there such a thing as a good solar-powered anchor light?

solar panel output voltage  The solution I’ve seen is to hook up a solar charger to the house battery, which is isolated from the other battery(s) by selector switch.  The solar panel tops up the battery during sunlight hours, and at night the anchor light has plenty of juice.  You’ll need to calculate the draw of your anchor light vs. solar panel output.  I’m assuming that the anchor light is turned off at daylight, which can also be accomplished automatically with a photo-sensitive switch.

Response:

writes: Path:

rocksanne!rochester!udel!news.sprintlink.net!howland.reston.ans.net!swiss.a ns.n et!prodigy.com!solar panel output voltage  where river traffic really demands that boats on moorings be lighted. But keeping an anchor light on a boat on a mooring is a problem. It’s too risky operating the anchor light on the ship’s main battery, since it tends to run the battery down quickly.  Self- contained battery operated anchor lights, like those made by Guest and ACR, work OK but the 6 volt batteries need to be changed too often.  Isn’t there a better way?   Some members of the club have tried using solar-powered sidewalk lights like you find in a hardware or garden store. While they are low-maintenance, they are also not very bright. I suppose they don’t stay lit all night long either, so there is room for improvement with this idea.   Does anyone have any bright ideas along this line solar panel output voltage

Bill I do not have a boat on a moorng but my dock does not have power.  The problem was solved by mounting a small 5 watt solar panel on the boat.  This keeps my Battery fully charged all season, The panel is only about a foot square and was priced about $80.  I measured the current flow even on cloud covered days, and here in Rochester N. Y . we get lots of them and I still get a trickle charge into the Bat.  I use a bit of power out sailing and have never had a low battery.  Seems like this would solve a lot of the Mooring problems of power. solar panel output voltage

Response:

Question:

I’m a little confused on your battery bank, as I thought 4-Ds were always 6 volts,off grid Solar Panel Inverter kits  so the two of them would always be used together. solar panel output ratings  Or did you mean that you had two sets of 4-D batteries?

No, they are just large 12V batteries.solar panel output ratings   They have three sections as opposed to the two in “normal” batteries.  I have replaced them and am planning on running them in parallel (switch in “ALL” position) and then recharging when they get low.  I haven’t installed the Heart Monitor that I bought yet, which will tell me when to recharge. I was just wondering if there was a clear-cut reason to alternate like I’ve been told.  I gues there is if the batteries are in different condition, since weak batteries will weaken strong ones, but in my case I feel it is better to consider them one large battery. You make a good point about the charger being so slow.  I have a 60Amp AC charger and am going to replace it with a Heart 2000 Inverter charger, so it should be ample.  I have a 55Amp alternator. off grid Solar Panel Inverter kits

Response:

Boy, this is a tough group.  I think I know a lot about my boat, thank you very much. solar panel output ratings  It’s battery banks that are unknown. Thanks for the info, I guess. — Captain Chuck Hey Cappy,  maybe I was hard on ya! Maybe I just heard the Coasties out saving a real “BOZO”  Maybe I don’t understand how you can know a boat and not understand battery banks. Just  to show ya how sweet  a guy I can be I throw another pearl. Get the book  ”Living on Ample Power”  West sells it and it is a pearl.solar panel output ratings  You and any other Battery Bank Deprived could make a living on it.off grid Solar Panel Inverter kits

Response:

Let me add something that I found out elsewhere that may be helpful to others. Another reason to alternate battery banks is in case a problem arises that sucks amps suddenly, you may notice the one bank go down rapidly and you have a reserve bank to diagnose the problem. solar panel output ratings  Whoever has been advising you to run one battery down and switch to the other has been giving you bad advice unless you have a very sophisticated energy management system which will sense the level of each battery and adjust the charge rate to each individually. Most chargers will operate at the demand rate for the lowest battery and could overcharge others in the bank. You refer in your post to “running your generator”, if you do in fact have a separate genset you should most certainly have one group 27 battery totally dedicated (not accessible by any other piece of equipment or parallel switch) to starting your genset. This way if you should discharge every other battery on the boat, you can always start the genset and use your charger to bring them back up. Every genset that I know of has a built in 12v charging circuit to keep its own battery up. 4D batteries have an average AH of 200-225 whereas the group 27 has between 105 and 115 AH. This means that you would require 4 group 27 to replace your existing batteries. If you do keep one as a dedicated engine starting battery and connect it via an isolator you could result in undercharging because there is up to 1.1 volts drop accross the average isolator. The principal cause of battery failure is one cell either shorting or becoming sulphated and this is no better or worse on 4Ds, 8Ds, 31s, 27s or 24s. The big advantage of having large banks of smaller batteries is that one with a defective cell can be taken out of service without losing a large segment of available power.off grid Solar Panel Inverter kits  However a major disadvantage is that this same defective battery, if left in service, will result in overcharging of the rest of the batteries in that same bank. A large bank of small batteries requiries the discipline of regular use of a hyrdrometer on every cell to catch the premature failure. Hope this helps, recommend you read the 12v Doctors Handbook for more info.

Go buy Nigel Calder’s Electrical/Mechanical guide. It cost  30 bucks and after you learn something about your boat you will have powerful knowledge that can never be taken from you. You also will no longer be thought of as a BOZO!

Boy, this is a tough group.  I think I know a lot about my boat, thank you very much.  It’s battery banks that are unknown. Thanks for the info, I guess. solar panel output ratings

Response:

Hopefully you will stick around and enjoy the more intelligent responses posted here… there are a few inarticulate, inconsiderate souls here who live for the sake of putting people down, but the rest of us are normal. In response to:”You also will no longer be thought of as a BOZO!”solar panel output ratings

Response:

Chuck, Awww, this group isn’t so tough.  It’s just that a few of the regulars forget that they don’t know all things about all things.  Most everyone else offers good, kind advice which makes this site a pleasure (usually) to visit each day.  Please don’t give up on us. Best wishes chucksolar panel output ratings Electrical/Mechanical guide.off grid Solar Panel Inverter kits  It cost  30 bucks and after you learn something about your boat you will have powerful knowledge that can never be taken from you. You also will no longer be thought of as a BOZO! Boy, this is a tough group.  I think I know a lot about my boat, thank you very much.  It’s battery banks that are unknown. Thanks for the info, I guess.solar panel output ratings

Response:

Just one comment about the way you have been told to run on batteries. Running them down to 11 volts is not a good idea. at 11.8 volts a typical lead/acid is fully discharged, taking even a traction battery beyond this point on a regular basis will significantly shorten its life. As a rough guide, 12.8 is fully charged, 12.5 is 30% discharged, 12.2 is 60% discharged. HTH Best regards,  Nigel with Crystal Light in Finlandsolar panel output ratings  My new boat has two 4D-2 batteries.  I have no experience with these batteries, so I have some questions. They aren’t holding a charge very long, so I assume they are shot.  One is dated 1993 and the other 1994.  I’m going to replace them both and start from scratch.  Am I better off with two new 4D’s or should I put a bunch (whatever fits) of smaller Series 27 batteries?  A side benefit to doing that would be the ability to dedicate one, through an isolator, to a starting battery. I’ve been told the way to run on batteries is to use one until it goes to 11 volts or so and then switch to the other one. When it reaches 11V run the generator and repeat the process. My gut feel tells me that running both together would yield the same results.  Why do it the other way?  This most likely will happen in the middle of the night and I could run one too low. I know you shouldn’t run weak batteries in parallel with strong batteries,off grid Solar Panel Inverter kits  but if they are both new, what is the difference? -solar panel output ratings

Response:

My new boat has two 4D-2 batteries.  I have no experience with these batteries, so I have some questions. They aren’t holding a charge very long, so I assume they are shot.  One is dated 1993 and the other 1994. solar panel output ratings  I’m going to replace them both and start from scratch.off grid Solar Panel Inverter kits   Am I better off with two new 4D’s or should I put a bunch (whatever fits) of smaller Series 27 batteries?  A side benefit to doing that would be the ability to dedicate one, through an isolator, to a starting battery.

I would recommend having a battery dedicated to starting the engine, in addition to the batteries described above.   A series 27 would be fine for starting battery.  But for the cabin battery, the two 4D batteries will provide a LOT more capacity than the number of 27 series batteries that would fit in the same space.solar panel output ratings  I’ve been told the way to run on batteries is to use one until it goes to 11 volts or so and then switch to the other one.

I’m a little confused on your battery bank, as I thought 4-Ds were always 6 volts, so the two of them would always be used together.  Or did you mean that you had two sets of 4-D batteries?   The advantage of operating them one at a time is that you will know how much battery you have left.  However, you will get much more battey life if you discharged both batteries to 50 percent instead of one battery to 20 percent and the other to 80 percent.  Plus, like you mentioned, if it reaches 20% at 2:00 AM, it’s likely to be left and be DEAD in the morning, which is very hard on a battery (and not too good for whatever it was running).off grid Solar Panel Inverter kits  When it reaches 11V run the generator and repeat the process.

You should run a few numbers and see if running your generator is going to make any significant difference to the state of battery charge.  I am guessing that each battery bank is about 200 amp-hours. Due to losses, you need to put in about 20% more amp-hours than you take out.solar panel output ratings   If the battery is drawn down to 20%, you have consumed 160 amp-hours, and you will need to put around 190 amp-hours to fully recharge it.   If you have a 30 amp “smart” charger, this will take over 6 hours.  If it is not a smart charger, it could take much longer (a dumb charger will only put out rated current into a dead battery.  The current drops off as the charge level increases).  In fact, if you have a ferro-resonant charger, you may get so little charge running off the generator that you won’t keep up with demand.   A 200 amp engine alternator with a smart voltage regulator can replace a lot in a hurry.  However, 200 amp charge rates is very hard on a 200 amp-hour battery!  If you must replace what you use each day, get a much larger battery bank and operate between 60 to 80 percent levels.off grid Solar Panel Inverter kits    solar panel output ratings

Response:

Go buy Nigel Calder’s Electrical/Mechanical guide. It cost  30 bucks and after you learn something about your boat you will have powerful knowledge that can never be taken from youoff grid Solar Panel Inverter kits . You also will no longer be thought of as a BOZO! solar panel output ratings

Response:

chuck:   need more info. What size engine? gas or diesel? how much draw on the house bank in amp hrs/day? what size boat?  two things I would suggest. 1. get a GOOD smart battery carger and limit the float to 13.30 v. 2. Forget the isolator and think in terms of a battery combiner. Cheers Bud – Hide quoted text — Show quoted text – My new boat has two 4D-2 batteries.  I have no experience with these batteries, so I have some questions. They aren’t holding a charge very long, so I assume they are shot.  One is dated 1993 and the other 1994.  I’m going to replace them both and start from scratch.  Am I better off with two new 4D’s or should I put a bunch (whatever fits) of smaller Series 27 batteries?  A side benefit to doing that would be the ability to dedicate one, through an isolator, to a starting battery. solar panel output ratings  I’ve been told the way to run on batteries is to use one until it goes to 11 volts or so and then switch to the other one.   When it reaches 11V run the generator and repeat the process.   My gut feel tells me that running both together would yield the same results.  Why do it the other way?  This most likely will happen in the middle of the night and I could run one too low.   I know you shouldn’t run weak batteries in parallel with strong batteries, but if they are both new, what is the difference? -off grid Solar Panel Inverter kits

Response:

My new boat has two 4D-2 batteries.solar panel output ratings   I have no experience with these batteries, so I have some questions. They aren’t holding a charge very long, so I assume they are shot.  One is dated 1993 and the other 1994.  I’m going to replace them both and start from scratch.  Am I better off with two new 4D’s or should I put a bunch (whatever fits) of smaller Series 27 batteries?  A side benefit to doing that would be the ability to dedicate one, through an isolator, to a starting battery. I’ve been told the way to run on batteries is to use one until it goes to 11 volts or so and then switch to the other one.   When it reaches 11V run the generator and repeat the process.    My gut feel tells me that running both together would yield the same results.  Why do it the other way?  This most likely will happen in the middle of the night and I could run one too low.   I know you shouldn’t run weak batteries in parallel with strong batteries, but if they are both new, what is the difference?solar panel output ratings

You are right Doug. I was referring to the internal voltage of the battery dropping so as not to supply as much current as the larger battery. It was my way of explaining why the smaller one would supply less energy. As it’s internal voltage drops, the amount of current that it supplies also drops. The larger one would probably not really do any charging of the smaller one as the percentage of each would drop equally. Regards Gary – Hide quoted text — Show quoted text – I think that the batteries will discharge according to their respective capacities. The smaller one never gets discharged to a lower voltage because the system always remains in equilibrium. There might be minor variations due to electrolyte depletion at the plates if a heavy load is applied but the equilibrinm would still be maintained. doug I should also have checked the electrolyte levels more often – I put over a litre of water in each cell of the Golf cart batteries, then discovered they were dead (but they were about 8 years old).  The other “half” of that parallel group was a 3 year old group 24 starting battery – it still seems OK.solar panel output ratings  This brings up a question, if anyone can shed some light . . . Is it reasonable or correct to connect batteries of different capacities in parallel, as the D and the G27 above?  I know the voltages are the same, but the capacities are not.  Any ideas? Jeff It’s actually a pretty serious no-no.  Here are a few reasons. First, on discharging, the low capacity battery will reach its state of full discharge before the high capacity battery.  At some point, it will be completely dead, and the high capacity battery won’t. Completely dead kills a battery if done a few times. Next, when partially discharged, the lower capacity battery will be more fully depleated than the higher capacity battery, causing the higher capacity battery to actually discharge into the lower capacity battery.  This is because the voltage of the lower capacity battery will drop faster than the voltage of the higher capacity battery.off grid Solar Panel Inverter kits  Once that happens, it’s like water flowing over a waterfall; it runs from the higher voltage battery to the lower one, but due to inefficiency in charging, power is not equally preserved.  You lose some.  So your weaker battery will cause the higher capacity battery to lose some of its charge more quickly than if it were isolated. This also means that the weaker battery will eventually kill the higher capacity one too. It may not be as bad as you think. Consider that the voltage drops on a battery as it discharges. If the smaller battery is in parallel with the larger one, the larger one will hold the voltage up on the smaller one as current is drawn from both. So as the smaller one gets somewhat depleted, it’s internal voltage that is produces will start to drop off. When that happens the current that it supplies will also drop off. This leaves the larger battery, which has maintained it’s internal voltage higher and thus will supply more of the current for the system. The larger one will tend to charge the smaller one if the voltage in the smaller one drops lower than the larger battery. So what really happens is both batteries will discharge approximately equally. If the small one gets discharged to 50% capacity, the large one will also get discharged to 50% capacity. solar panel output ratings

Response:

You can do it but it is not recommended. When you discharge the bank the individual batteries will discharge to different levels. Maybe 20% for the larger battery and 50% for the smaller one. This in itself is not terrible but the lifetime of the smaller battery will be reduced. When the small battery starts to reach its autumn years it will degrade the bank and also most likely cause the larger battery to suffer a premature death. The best way to go is to buy all the batteries for a bank from the same manufacturer and dealer of all the same size and model. Charge each individually, then wire them in parallel and enjoy the fact that you have done everything possible to have a reliable bank that will provide many years of reliable service. doug – Hide quoted text — Show quoted text – I should also have checked the electrolyte levels more often – I put over a litre of water in each cell of the Golf cart batteries, then discovered they were dead (but they were about 8 years old).  The other “half” of that parallel group was a 3 year old group 24 starting battery – it still seems OK. This brings up a question, if anyone can shed some light . . . Is it reasonable or correct to connect batteries of different capacities in parallel, as the D and the G27 above?off grid Solar Panel Inverter kits   I know the voltages are the same, but the capacities are not.  Any ideas?solar panel output ratings

Response:

<<<<<If you had a battery monitor installed you could have detected the dead battery very quickly. It does drive the system cost up a couple of hundred dollars though. Instead of running out and buying a fancy panel I would suggest  replacing your battery switch with a Guest Smart Switch.  It shows the state of charge and state of charging when the engine is running with a series of accurate LEDs. Cost about $70.solar panel output ratings  Express 30 “Ringmaster” Trains are a winter sport

Response:

Actually, now that I think about it, no matter what the sizes of the batteries are, if they have been connected in parallel they will charge and discharge in step with each other. Granted the larger bank is going to contribute more energy than the small one. So if one battery is twice the size of the other, after discharging the bank say 90AH, the large battery will be down 60AH while the smaller one will be down 30AH. Both will be down the same percentage of their total capacity. This assumes the batteries are fairly new. As the batteries age their respective capacities will diminish but not necessarily at the same rate. The equilibrium will still exist with each battery contributing to the total load according to its present capacity. As long as the batteries are kept in parallel while charging and discharging, there will be no current flow between the batteries.solar panel output ratings  If you disconnect them from each other you will always find that the voltages on the batteries are the same. This is, of course, the ideal situation. None of these things are linear and the remaining capacity of the batteries is subject to Peuckert’s equation at any given time. To look at it another way, two batteries in parallel are theoretically equivalent to one battery with the plate area being the sum of the areas of the two batteries. Similar to capacitors in the physical sense. Because of differences in construction, chemistry, etc this is not the actual reality but it is an approximation. When discharging 2/3 of the energy provided is contributed by 2/3 of the area of each plate. doug – Hide quoted text — Show quoted text – I should also have checked the electrolyte levels more often – I put over a litre of water in each cell of the Golf cart batteries, then discovered they were dead (but they were about 8 years old).  The other “half” of that parallel group was a 3 year old group 24 starting battery – it still seems OK. This brings up a question, if anyone can shed some light . . . Is it reasonable or correct to connect batteries of different capacities in parallel, as the D and the G27 above?  I know the voltages are the same, but the capacities are not.  Any ideas? Jeff It’s actually a pretty serious no-no.  Here are a few reasons. First, on discharging, the low capacity battery will reach its state of full discharge before the high capacity battery.  At some point, it will be completely dead, and the high capacity battery won’t. Completely dead kills a battery if done a few times. Next, when partially discharged, the lower capacity battery will be more fully depleated than the higher capacity battery, causing the higher capacity battery to actually discharge into the lower capacity battery.  This is because the voltage of the lower capacity battery will drop faster than the voltage of the higher capacity battery. Once that happens, it’s like water flowing over a waterfall; it runs from the higher voltage battery to the lower one, but due to inefficiency in charging, power is not equally preserved.  You lose some.  So your weaker battery will cause the higher capacity battery to lose some of its charge more quickly than if it were isolated.off grid Solar Panel Inverter kits  This also means that the weaker battery will eventually kill the higher capacity one too. solar panel output ratings

Response:

I should also have checked the electrolyte levels more often – I put over a litre of water in each cell of the Golf cart batteries, then discovered they were dead (but they were about 8 years old).  The other “half” of that parallel group was a 3 year old group 24 starting battery – it still seems OK.

This brings up a question, if anyone can shed some light . . . Is it reasonable or correct to connect batteries of different capacities in parallel, as the D and the G27 above?  I know the voltages are the same, but the capacities are not.  Any ideas?off grid Solar Panel Inverter kits

Response:

I think that the batteries will discharge according to their respective capacities. The smaller one never gets discharged to a lower voltage because the system always remains in equilibrium. There might be minor variations due to electrolyte depletion at the plates if a heavy load is applied but the equilibrinm would still be maintained. off grid Solar Panel Inverter kits?  I know the voltages are the same, but the capacities are not.  Any ideas? Jeff It’s actually a pretty serious no-no.  Here are a few reasons. First, on discharging, the low capacity battery will reach its state of full discharge before the high capacity battery.  At some point, it will be completely dead, and the high capacity battery won’t.v  Completely dead kills a battery if done a few times. Next, when partially discharged, the lower capacity battery will be more fully depleated than the higher capacity battery, causing the higher capacity battery to actually discharge into the lower capacity battery.  This is because the voltage of the lower capacity battery will drop faster than the voltage of the higher capacity battery. Once that happens, it’s like water flowing over a waterfall; it runs from the higher voltage battery to the lower one, but due to inefficiency in charging, power is not equally preserved.  You lose some.  So your weaker battery will cause the higher capacity battery to lose some of its charge more quickly than if it were isolated. This also means that the weaker battery will eventually kill the higher capacity one too. It may not be as bad as you think. Consider that the voltage drops on a battery as it discharges. If the smaller battery is in parallel with the larger one, the larger one will hold the voltage up on the smaller one as current is drawn from both. So as the smaller one gets somewhat depleted, it’s internal voltage that is produces will start to drop off. When that happens the current that it supplies will also drop off. This leaves the larger battery, which has maintained it’s internal voltage higher and thus will supply more of the current for the system. The larger one will tend to charge the smaller one if the voltage in the smaller one drops lower than the larger battery. So what really happens is both batteries will discharge approximately equally. If the small one gets discharged to 50% capacity, the large one will also get discharged to 50% capacityv.

Response:

solar panel output ratings  I should also have checked the electrolyte levels more often – I put over a litre of water in each cell of the Golf cart batteries, then discovered they were dead (but they were about 8 years old).  The other “half” of that parallel group was a 3 year old group 24 starting battery – it still seems OK. This brings up a question, if anyone can shed some light . . . Is it reasonable or correct to connect batteries of different capacities in parallel, as the D and the G27 above?  I know the voltages are the same, but the capacities are not.  Any ideas? Jeff It’s actually a pretty serious no-no.  Here are a few reasons. First, on discharging, the low capacity battery will reach its state of full discharge before the high capacity battery.  At some point, it will be completely dead, and the high capacity battery won’t. Completely dead kills a battery if done a few times. Next, when partially discharged, the lower capacity battery will be more fully depleated than the higher capacity battery, causing the higher capacity battery to actually discharge into the lower capacity battery.  This is because the voltage of the lower capacity battery will drop faster than the voltage of the higher capacity battery. Once that happens, it’s like water flowing over a waterfall; it runs from the higher voltage battery to the lower one, but due to inefficiency in charging, power is not equally preserved.  You lose some.  So your weaker battery will cause the higher capacity battery to lose some of its charge more quickly than if it were isolated.off grid Solar Panel Inverter kits  This also means that the weaker battery will eventually kill the higher capacity one too. solar panel output ratings

It may not be as bad as you think. Consider that the voltage drops on a battery as it discharges. If the smaller battery is in parallel with the larger one, the larger one will hold the voltage up on the smaller one as current is drawn from both. So as the smaller one gets somewhat depleted, it’s internal voltage that is produces will start to drop off. When that happens the current that it supplies will also drop off. This leaves the larger battery, which has maintained it’s internal voltage higher and thus will supply more of the current for the system. The larger one will tend to charge the smaller one if the voltage in the smaller one drops lower than the larger battery. So what really happens is both batteries will discharge approximately equally. If the small one gets discharged to 50% capacity, the large one will also get discharged to 50% capacity.off grid Solar Panel Inverter kits

Response:

Thanks for all the good suggestions from the group.  I will be using the batteries in parallel but have the ability to easily switch them in and out of the circuit for monitoring.  I have a charge controller made by MorningStar (Sunsaver 6) ( solar panel output ratings   and I read about 18V from the solar panel in bright sun and measure the load voltage of about 13.8V to a fully charged battery.  haven’t measured the charging current but the Siemans P75 specs. indicate about 4.5 Amps.  I am sure the current to the fully charged battery is limited to a very small value but I will be measuring this soon. solar panel output ratings

Response:

(I have twice (on different boats) had a really dead battery in parallel with a good one, and only noticed that a battery was dead when I tried to use the dead one alone.)

I hope you realize that you have too much battery capacity on your boats.  If you have a dead battery and don’t know it, you don’t need it, and are wasting money to replace it. solar panel output ratings

Response:

That’s an enlightened comment. What you are implying is that you must use every amp-hour of your capacity on every trip in order to justify having it. That’s silly. First of all having reserve power is never a bad idea. I can run 3 or 4 days days on a charge if I want to but I wouldn’t be sailing much if I only went out when I had 3 or 4 days available. I had an alternator blow a diode a few years back. I was able to continue my trip without interruption because I had enough reserve power. Using this logic I suspect that your  fuel tank is way too large, and your boat has way too much bouyancy, your fridge holds way too much beer, your holding tank is way oversized, and your wheel has too many turns. doug off grid  Solar Panel Inverter kits I have twice (on different boats) had a really dead battery in parallel with a good one, and only noticed that a battery was dead when I tried to use the dead one alone.) I hope you realize that you have too much battery capacity on your boats.  If you have a dead battery and don’t know it, you don’t need it, and are wasting money to replace it. solar panel output ratings

Response:

off grid Solar Panel Inverter kits  If you had a battery monitor installed you could have detected the dead battery very quickly. It does drive the system cost up a couple of hundred dollars though. doug v Looking for some advice.  I have three #27 batteries I am putting aboard my sailboat and will be charging using a 75W solar panel. Two of these deep cycle batteries are new and one is a few years old but seems to be in good shape. I am trying to decide how to configure the batteries as “house batteries” with switches and the charge controller.  My initial plan is to is to draw power from all batteries in parallel so that their charge levels remain equalized and to also have the output of the solar charge controller connected to them in parallel as well. Is this a good plan or does anyone think it would be best to selectively switch each battery in and out of the bank and to do the same with the charging from the solar charge controller? The usual recommendation is that parallelled batteries should all be of the same vintage – however, I’ve parallelled batteries of different ages with no apparent problem. My only suggestion is that you should have a means of using any one of the (normally) parallelled batteries by itself, so you can periodically check each battery to see if it is OK.  (I have twice (on different boats) had a really dead battery in parallel with a good one, and only noticed that a battery was dead when I tried to use the dead one alone.) — Peter Bennett, VE7CEI new newsgroup users info :solar panel output ratings

Response:

I assume you consider battery capacity like money: “You can never have too much.”  I don’t see things that way. Why don’t you carry a spare alternator?  Or better yet, why don’t you install a second alternator?  That would cover the scenario where the battery you don’t need shorts and takes out the battery you do need.  Or maybe a second engine in case…. Just more enlightened comments from someone who thinks that if you carry equipment that you can’t tell if it works or not feels that you are carrying extra ballast. The real answer is to install a battery monitor and read the instruction book so you know if your batteries are functioning. -solar panel output ratings

-That’s an enlightened comment. What you are implying is that you must use every amp-hour of your capacity on every trip in order to justify having it. That’s silly. First of all having reserve power is never a bad idea. I can run 3 or 4 days days on a charge if I want to but I wouldn’t be sailing much if I only went out when I had 3 or 4 days available. I had an alternator blow a diode a few years back. I was able to continue my trip without interruption because I had enough reserve power. Using this logic I suspect that your  fuel tank is way too large, and your boat has way too much bouyancy, your fridge holds way too much beer, your holding tank is way oversized, and your wheel has too many turns. doug (I have twice (on different boats) had a really dead battery in parallel with a good one, and only noticed that a battery was dead when I tried to use the dead one alone.) I hope you realize that you have too much battery capacity on your boats. off grid Solar Panel Inverter kits  If you have a dead battery and don’t know it, you don’t need it, and are wasting money to replace it solar panel output ratings

Response:

off grid Solar Panel Inverter kits  I think that the guy that replied about not knowing that the second parallel battery was bad was trying to make the point that when a battery goes bad that is in parallel with another one doesn’t always kill the good one. That was what the original post was about. A bad battery killing a good one in parallel with it. As for your point about “too much battery capacity”, you never have too much! The reason I say that is that although you may be able to get by with one battery, doubling the capacity will increase the life expectancy and reliability. If you have a 100 amp hour battery and the power requirements of the boat are say 50 amp hours for a given trip, that means that you will be discharging the battery to 50% of its capacity solar panel output ratings With 2 batteries in parallel you now have 200 amp hour capacity. If you use the same 50 amp hours of power that only draws the batteries down 25%. You will get much more life out of them doing that than you will drawing them down 50% every time. Plus you will have more reserve capacity if you should need it. If one of the batteries does go bad, you still can draw the 50 amps off the one battery (and not know the other is bad as the poster said) although it will be more stress on the one battery. And yes, some people do carry spare alternators too. Regards Garyoff grid Solar Panel Inverter kits  I assume you consider battery capacity like money: “You can never have too much.”  I don’t see things that way. Why don’t you carry a spare alternator?  Or better yet, why don’t you install a second alternator?  That would cover the scenario where the battery you don’t need shorts and takes out the battery you do need.  Or maybe a second engine in case…. Just more enlightened comments from someone who thinks that if you carry equipment that you can’t tell if it works or not feels that you are carrying extra ballast. The real answer is to install a battery monitor and read the instruction book so you know if your batteries are functioning. — Tom s/v Xanthus That’s an enlightened comment. What you are implying is that you must use every amp-hour of your capacity on every trip in order to justify having it. That’s silly. First of all having reserve power is never a bad idea. I can run 3 or 4 days days on a charge if I want to but I wouldn’t be sailing much if I only went out when I had 3 or 4 days available. I had an alternator blow a diode a few years back. I was able to continue my trip without interruption because I had enough reserve power. Using this logic I suspect that your  fuel tank is way too large, and your boat has way too much bouyancy, your fridge holds way too much beer, your holding tank is way oversized, and your wheel has too many turns. doug (I have twice (on different boats) had a really dead battery in parallel with a good one, and only noticed that a battery was dead when I tried to use the dead one alone.) I hope you realize that you have too much battery capacity on your boats.  If you have a dead battery and don’t know it, you don’t need it, and are wasting money to replace it.solar panel output ratings

Response:

Peter, If you had a battery monitor installed you could have detected the dead battery very quickly. It does drive the system cost up a couple of hundred dollars though.

I do have a monitor – part of the Heart/Interface inverter control – but you _do_ have to look at it from time to time for it to help solar panel output ratings I should also have checked the electrolyte levels more often – I put over a litre of water in each cell of the Golf cart batteries, then discovered they were dead (but they were about 8 years old).  The other “half” of that parallel group was a 3 year old group 24 starting battery – it still seems OK. off grid Solar Panel Inverter kits     new newsgroup users infosolar panel output ratings

Response:

Oh, well there is that dougsolar panel output ratings, If you had a battery monitor installed you could have detected the dead battery very quickly. It does drive the system cost up a couple of hundred dollars though. I do have a monitor – part of the Heart/Interface inverter control – but you _do_ have to look at it from time to time for it to help  off grid Solar Panel Inverter kits  I should also have checked the electrolyte levels more often – I put over a litre of water in each cell of the Golf cart batteries, then discovered they were dead (but they were about 8 years old).  The other “half” of that parallel group was a 3 year old group 24 starting battery – it still seems OK. — Peter Bennett, VE7CEI new newsgroup users info solar panel output ratings

Response:

solar panel output ratings  Some of the monitors are easier to wire than others. I had a e-meter (link 10 is the same thing) that was a snap to install. Never had any problems with it. Now I have an ESP (Ample Power) which is a little more complicated. Be careful about discount house batteries like Sam’s, BJ’s, etc. A friend of mine bought 8 golf-cart batteries from BJ’s a few years ago. They said they were made by Trojan on them but were alot cheaper. Out of curiosity I called Trojan and talked to an engineer and asked him what the scoop was. He said that the batteries made by Trojan and sold in discount stores are intended to be used by OEMs in  floor polishers. The plates are the same construction but the plate separators are much inferior to those used in the genuine maroon case Trojan golf-cart battery (T-105). The cheaper batteries are made for the OEM market where you can’t justify putting a $60 battery in a $150 floor polisher. Also, checking a battery in the store with a voltmeter isn’t going to tell you much other than if a gross problem exists. They have been sitting self-discharging since they came out of the factory. If one were way low then that is definitely one not to buy. The only way to really know what the story is is to charge the battery, let it sit unconnected for a day and then measure the voltage. Next would be a capacity test but then that is only meaningful after the battery is broken in (20-50 cycles). So the bottom line is to buy well regarded brand name batteries from a reputable dealer and then take good care of them. You save money in the long run. Anything else is the luck of the draw. I’ve seen batteries from BJ’s work well and last for years and I’ve seen others that died after a couple of years, and other that were DOA. doug  off grid Solar Panel Inverter kits If you had a battery monitor installed you could have detected the dead battery very quickly. It does drive the system cost up a couple of hundred dollars though. Though I agree and have one, I’m finding I’m having more trouble with the monitor’s wiring than the actual batteries. Yes, most of the problem is with my “jere rigging”, but….. Bought two batteries at the same time from the same place in April. After a season, I’ve finally decided that one was actually DOA, though it serves just fine as the reserve starting battery. I’m going to try to get that one replaced of course, but if that fails, I’ll get one like the one that DID work right and parallel that with the other good one as the house bank. Lesson learned: taking a digital voltmeter to the “Sam’s Club” or whatever and choosing only the best battery(ies) is a good thing.solar panel output ratings

Rsolar panel output ratings”  I don’t see things that way.

No, not true. Too much is a waste of money, too heavy, too much space, too hard to keep chargedoff grid Solar Panel Inverter kits  However, having a reserve does not mean having too much. Why don’t you carry a spare alternator?

I do. Or better yet, why don’t you install a second alternator?

I have. That would cover the scenario where the battery you don’t need shorts and takes out the battery you do need.

I don’t have a battery I don’t need. Having a larger battery bank extends the total lifetime of all batteries inthe bank. Thus I save money in the long run.  Or maybe a second engine in case….

The diesel alternator I am installing is a second engine + alternator. Just more enlightened comments from someone who thinks that if you carry equipment that you can’t tell if it works or not feels that you are carrying extra ballast.

I can always tell if it is working. If not, then it is a poorly designed system. The real answer is to install a battery monitor and read the instruction book so you know if your batteries are functioning.

Absolutely. off grid Solar Panel Inverter kits t. What you are implying is that you must use every amp-hour of your capacity on every trip in order to justify having it. That’s silly. First of all having reserve power is never a bad idea. I can run 3 or 4 days days on a charge if I want to but I wouldn’t be sailing much if I only went out when I had 3 or 4 days available. I had an alternator blow a diode a few years back. I was able to continue my trip without interruption because I had enough reserve power. Using this logic I suspect that your  fuel tank is way too large, and your boat has way too much bouyancy, your fridge holds way too much beer, your holding tank is way oversized, and your wheel has too many turns. doug (I have twice (on different boats) had a really dead battery in parallel with a good one, and only noticed that a battery was dead when I tried to use the dead one alone.) I hope you realize that you have too much battery capacity on your boats.  If you have a dead battery and don’t know it, you don’t need it, and are wasting money to replace it.off grid Solar Panel Inverter kits

Response:

Bob, You might consider the BATTERY BRAIN. You’ll never have to worry about a dead battery in your boat again. Constantly monitors your battery’s condition Great for boats that are stored or not started for long periods of time Even if lights or electronic accessories are left on you won’t have to worry about getting stranded. When the engine is off and the battery is in danger of going dead due to a short or excessive drain the Battery Brain automatically switches off all battery current draw to save enough reserve power to ensure that your   boat starts. All you have to do then is press the “Reset” button on the Battery Brain or press the remote control button to start the boat.off grid Solar Panel Inverter kits , a panel can cook battereis in no time if there is no load (like during the week if the boat is unsued, etc…) solar panels can go way up there in voltage (like 17 – 18), if the load gets very light (like just fully charged batteries) Thre are some really nice, reasonably priced voltage regulators/charge controllers available, I used one from West Marine, it had two separate outputs, so I could leave my batteries separate while unused/charging, this helped prevent a bad battery pulling he other down, etc… Cheers,

Response:

Two of these deep cycle batteries are new and one is a few years old but seems to be in good shape.  My initial plan is to is to draw power from all batteries in parallel so that their charge levels remain equalized and to also have the output of the solar charge controller connected to them in parallel as well.

The main problem with batteries in parallel is that they will all live and die together.     This idea works fine if you buy all the batteries at the same time and just accept that when one goes bad, your entire battery bank goes bad. In your situation, it not be wise to parallel a “few year old” battery with new batteries.  When that old battery gives up and dies it will drag down the others as well.

Looking for some advice.  I have three #27 batteries I am putting aboard my sailboat and will be charging using a 75W solar panel. Two of these deep cycle batteries are new and one is a few years old but seems to be in good shape. I am trying to decide how to configure the batteries as “house batteries” with switches and the charge controller.  My initial plan is to is to draw power from all batteries in parallel so that their charge levels remain equalized and to also have the output of the solar charge controller connected to them in parallel as well. Is this a good plan or does anyone think it would be best to selectively switch each battery in and out of the bank and to do the same with the charging from the solar charge controller?

The usual recommendation is that parallelled batteries should all be of the same vintage – however, I’ve parallelled batteries of different ages with no apparent problem. My only suggestion is that you should have a means of using any one of the (normally) parallelled batteries by itself, so you can periodically check each battery to see if it is OK.  (I have twice (on different boats) had a really dead battery in parallel with a good one, and only noticed that a battery was dead when I tried to use the dead one alone.) — Peter Bennett, VE7CEI     new newsgroup users infosolar panel output ratings

Response:

The others gave good advice about paralelling or not.. I’ll add one more thing, get a good charge controller, a panel can cook battereis in no time if there is no load (like during the week if the boat is unsued, etc…) solar panels can go way up there in voltage (like 17 – 18), if the load gets very light (like just fully charged batteries) Thre are some really nice, reasonably priced voltage regulators/charge controllers available, I used one from West Marine, it had two separate outputs, so I could leave my batteries separate while unused/charging, this helped prevent a bad battery pulling he other down, etc… Cheers, — Steve   (remove anti spam XYX in return address for correct email)

Response:

Looking for some advice.  I have three #27 batteries I am putting aboard my sailboat and will be charging using a 75W solar panel. Two of these deep cycle batteries are new and one is a few years old but seems to be in good shape. I am trying to decide how to configure the batteries as “house batteries” with switches and the charge controller.  My initial plan is to is to draw power from all batteries in parallel so that their charge levels remain equalized and to also have the output of the solar charge controller connected to them in parallel as well. Is this a good plan or does anyone think it would be best to selectively switch each battery in and out of the bank and to do the same with the charging from the solar charge controller? Look forward to getting the opinions of others in our newsgroup. solar panel output ratings

Response:

Thanks Rod and Peter, After reading your responses,off grid Solar Panel Inverter kits  I think I will use two battery switches and wire them so that I can select  all the batteries or individually select them to supply the “house circuit.”  Going back to the drawing board and make some new diagrams for this tonight.   Thanks for your responses.solar panel output ratings

Response: