vtchris Posted November 12, 2014 Share Posted November 12, 2014 I am doing some research and need some advice on batteries. I have solar, 135W roof panel and my coach battery is starting to go. It is a 12v AGM about 7 years old. I am thinking of getting two 6v AGMs. What would you recommend? Any particular place to buy? My controller is 35 amp and my inverter is 800W. Oh, and my rig still has the original converter and it runs for hours and hours when I hook into shore power after boondocking for a week or two. Should I get a switch installed to turn it off? Seems to me as long as the sun is shining I don't need it. Thanks for any help! Chris - 1994 Warrior Quote Link to comment Share on other sites More sharing options...
Maineah Posted November 13, 2014 Share Posted November 13, 2014 You may have a decent charger in your 94 and it maybe normal for it to run a lot the older ones not so much do you know the model number? Quote Link to comment Share on other sites More sharing options...
vtchris Posted November 13, 2014 Author Share Posted November 13, 2014 Model no. 6332. Quote Link to comment Share on other sites More sharing options...
WME Posted November 13, 2014 Share Posted November 13, 2014 If I remember correctly a 6332 has a charge rate of around 3 amps. How many AH is your current battery and what would be the AH of your new batteries Quote Link to comment Share on other sites More sharing options...
vtchris Posted November 13, 2014 Author Share Posted November 13, 2014 How do I find this information? The guy who will do the install said the new 6v's are "394 minutes at 25 amps" whatever that means. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted November 13, 2014 Share Posted November 13, 2014 The fitting of a pair of Trojan T-105 (golf cart, 6v each) is a popular choice. 447 minutes @ 25 amps. http://www.trojanbattery.com/product/t-105/ If, of course, you have the physical space available. Quote Link to comment Share on other sites More sharing options...
zero Posted November 13, 2014 Share Posted November 13, 2014 I am doing some research and need some advice on batteries. I have solar, 135W roof panel and my coach battery is starting to go. It is a 12v AGM about 7 years old. I am thinking of getting two 6v AGMs. What would you recommend? Any particular place to buy? My controller is 35 amp and my inverter is 800W. Oh, and my rig still has the original converter and it runs for hours and hours when I hook into shore power after boondocking for a week or two. Should I get a switch installed to turn it off? Seems to me as long as the sun is shining I don't need it. Thanks for any help! Chris - 1994 Warrior No personal offense but I think a person must have a screw loose in their head if opting for an AGM over a conventional flooded lead-acid battery (FLA type). There is NO gain with an AGM for normal usage. Just down-side and added expense. AGMs were designed for using in difficult locations where they could be mounted upside down, or in areas where less off-gassing was essential. By far, convetional deep-cycle batteries give the best bang for the buck for solar and/or RV use. In the long run, they often cost half as less. Many places want to push them now because they are much easier to ship. They can even be air-shipped. FLAs have to be truck shipped. As to Trojans - the lesser of the Trojan bunch - the T-105 golf-cart batteries used to be $45 each and were great bargains. Not so much anymore unless you live near a golf course that buys big lots and will give you deals. Deka makes a T-105 equivlant that you can order in at any NAPA store. Better deal. My set of Dekas in 9 years old and still working OK. Model GC2s. Just keep in mind that these type batteries are 6 volt so you must have at least two, or four. That makes them unhandy to use in other things when not using the RV. The 12 volt deep-cycle batteries Walmart sells as type 24, 27, or 29 are excellent buys. Made by Johnson Controls. No they won't last as long as a Trojan but are also cheaper. And when not being used in your RV, you can use as a starting battery in a boat, truck, car, farm tractor, etc. Quote Link to comment Share on other sites More sharing options...
vtchris Posted November 13, 2014 Author Share Posted November 13, 2014 That's my point.....I need to install them where gassing off would be a problem. Quote Link to comment Share on other sites More sharing options...
zero Posted November 13, 2014 Share Posted November 13, 2014 The biggest downside to Trojans - at least where I am is they require shipping fees. And if there's ever a warranty issue - shipping fees again. With the Dekas - no fees since NAPA handles all that. Quote Link to comment Share on other sites More sharing options...
zero Posted November 13, 2014 Share Posted November 13, 2014 That's my point.....I need to install them where gassing off would be a problem. AGMs gas also. Not as much as FLAs but they still require fresh-air venting when put into an RV. Quote Link to comment Share on other sites More sharing options...
linda s Posted November 13, 2014 Share Posted November 13, 2014 I don't know where Chris's battery compartment is but not having to get to the battery and add water is a biggy for some of us. My battery has to be removed completely to do this. I still manage OK but I would like bigger than the 24 group in there and even upgrading to a 27 adds another 10lbs. Linda S Quote Link to comment Share on other sites More sharing options...
zero Posted November 13, 2014 Share Posted November 13, 2014 If you get looking closely at specific AGMs, watch for claims about them not needing venting. It's is not true and you'd be hard pressed to find a AGM company that makes such a statement. Unlike FLA batteries, VRLA batteries like AGMs use a relief valve. It lets pressure build up inside the battery and when internal gas reaches a certain pressure - that valve opens and the gas escapes. Thus the need for the venting. FLA conventional batteries have no valve and freely off-gas whenever needed. VRLA (valve regulated lead acid) AGMs save up built-up gas and let it out when it reaches a preset pressure. My main beef with AGMs is their high price and often, short life. I've seen many, many fail in solar electric banks when only at half the service life of batteries like Trojans or Rolls-Surettes that were only half the price. Quote Link to comment Share on other sites More sharing options...
zero Posted November 13, 2014 Share Posted November 13, 2014 I don't know where Chris's battery compartment is but not having to get to the battery and add water is a biggy for some of us. My battery has to be removed completely to do this. I still manage OK but I would like bigger than the 24 group in there and even upgrading to a 27 adds another 10lbs. Linda S Yes, probably everything has its advantages and disadvantages. I don't regard adding water to a battery maybe once a year a big deal. Is it sometimes a pain? Yes. So is buying gas, and fixing anything that breaks or needs service. Like all the rest, AGMs have their advantages and disadvantages. I DO know they are often misrepresented by sellers and often buyers choose them for the wrong reasons. They were first developed as I recall for use in spaceships. Later race cars that might roll over and spill acid all over the driver. In RVs? Guess one needs to weigh the true pros and cons and decide if the extra cost is worth it. Quote Link to comment Share on other sites More sharing options...
WME Posted November 13, 2014 Share Posted November 13, 2014 I have AGMs inside and have no outgassing problems. Typically AGM only outgas when badly overcharged. There are gas proof battery boxes, they are designed to vent through a 2" or so vent hose. The main point I was headed for is that 2 6v batteries will take 2x as long to charge as what you have now. Quote Link to comment Share on other sites More sharing options...
zero Posted November 13, 2014 Share Posted November 13, 2014 Yes and I have many conventional FLA batteries and also have no off-gassing problems. I simply use a vent as is also required with AGMs. Can't comment on recharge time issues. What you take out of any battery bank needs to go back in - regardless of what sort of battery. Draw 20 amps for four hours - you need to put 20 amps back in for four hours, or 40 amps in for two hours (if the batteries can handle the charge rate). I typically camp at night for 8-10 hours and then drive all day. Plenty of surplus time to charge my batteries. Quote Link to comment Share on other sites More sharing options...
zero Posted November 13, 2014 Share Posted November 13, 2014 One other thing I forgot to mention. All batteries self-discharge even when hooked to nothing. I.e. they go dead all on their own. At cold temps near zero F - AGMs and FLA work pretty much the same. They both lose 10 - 20% of their charge in 6 months. But at warm temps around 80 F - an AGM only loses 25% of its charge in 6 months. A FLA loses 50%. Not a meaningful issue for a vehicle that gets started once in awhile or is on a battery maintainer. Quote Link to comment Share on other sites More sharing options...
vtchris Posted November 13, 2014 Author Share Posted November 13, 2014 I am a full timer and boondock a lot, so keep that in mind. My present 12v just barely fits in the exterior vented battery compartment. But right behind and a bit above is the underneath of my dinette bench seat. I have plenty of room there. Plus my inverter and controller are under the table so that makes wiring simple. Thanks for all your advise. I think I am learning more than I ever wanted to know! But better to be an informed customer. Quote Link to comment Share on other sites More sharing options...
WME Posted November 13, 2014 Share Posted November 13, 2014 Well the first question is, Does what you have work for you now??? Or do you NEED the extra capacity of 2 6v monsters? Quote Link to comment Share on other sites More sharing options...
zero Posted November 13, 2014 Share Posted November 13, 2014 I am a full timer and boondock a lot, so keep that in mind. My present 12v just barely fits in the exterior vented battery compartment. But right behind and a bit above is the underneath of my dinette bench seat. I have plenty of room there. Plus my inverter and controller are under the table so that makes wiring simple. Thanks for all your advise. I think I am learning more than I ever wanted to know! But better to be an informed customer. I guess it all depends on how many mods you want to make. I put two type 29 12-volt deep-cycle batteries in my 1988 Minicruiser. One in the original plastic battery box with vent hose under the bed/couch. I put the other battery in the tool-box compartment that has a door to access it from the outside. I no longer need it for tools or jack since I installed a rear carry box. I just put a vent in the access door and it worked great. Actually still room for some tools in there. I have the two 12 volt DC #29 batteries. Also two inverters - a mod-wave 1200 watt and a so-called "sine-wave" 3000 watt. Also a microwave that works well without any engines running anywhere. Also have #2 AWG copper running from the alternator in front by the engine all the way for extra charge power capacity or "sharing front and back batteries" if wanted. Also have an on-board marine battery maintainer that has two isolated outputs. Rated 10 amp max and maintains the front cranking battery and the rear "house" batteries when parked. All fit in very nicely with room to spare. I use a 150 amp continuous rated relay to connect the front and back batteries and it's controlled automatically with a voltage sensing module. Once the front cranking battery goes over 13 volts - it trips on and sends charge current to the rear "house" batteries. Quote Link to comment Share on other sites More sharing options...
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