I have always used flooded lead acid batteries in my previous Class C and now in my diesel Class A. I have been good about doing regular maintenance and always get good life out of the batteries, although the mess of the lead acid batteries requires constant clean up to keep from eating the metal braces in the battery compartment. My motorhome is always connected to shore power at home and on the road (other than the occasional 8 hour quiet hours dry camp at one military base that is a popular place). My inverter has a setting for OVERTEMP OVERLOAD/AGM (so I assume I would use that one). My question is whether the AGM batteries will have reduced life since they would rarely approach discharge with the batteries would stay recharging most times. I'm getting older and the less maintenance the better, so I'm wondering if the extra expense will be worth the reduced maintenance, and still get the same or better life from the house batteries .....

AGM batteries are actually designed for that application, their first use was as backup batteries that sat under trickle charge for years waiting to start backup generators. They also can be cycled down to 20% without damage (somewhat reduced life, but not damage) and can be charged about 3 times as fast. They also retain a useful charge for up to two years without charging. If your inverter has an AGM setting it should float (or trickle) charge at around 13.6 volts.Brian

Well maintained lead acid batteries will last a long time, I got 13 years out of my factory set of batteries. AGM batteries will not last as long, say 4 years or so, if you keep them full most of the time, you might get one more year. That said, a not so well maintained lead acid battery might only last a year or two. Let them run dry, or sit uncharged for a time, and the battery will suffer, and not give a long service life. Many DP's get AGM batteries because the owners will not look at the batteries like you have done, and are OK with replacing them every 4-5 years. I will stay with lead acid batteries for now, But as I get older I might change to AGM when I do not want to mess with them anymore - just like you are thinking. Sorry to not give you a clear answer. But if you want 0 maintenance, and replacement after 4-5 years, then AGM is for you, at the additional expense. Fred.

Maintain the batteries at 13.2 volts and no higher.Once a month increase voltage to 14.4 for 2 hours then revert back to 13.2Calibrated for 25C temps.

Are you over filling the wet cells? Should be 1/8" to 1/4" below the split ring that extends down into the cell. Just touching is absolute max.Flooded batteries do use more water toward end of life.Is your float voltage too high? Should be 13.2v most warm days. Even a bit lower in very hot weather (95+).Are you using anything to protect against terminal corrosion?Is the compartment well ventilated? Is the battery in a direct vented box?

I've had my AGM batteries for over five years. They recharge ridiculously fast so I don't have to drive far to my next dry camp site. They hold a charge as well as ever and I would never go back to lead acid batteries. Just my personal experience.

AGM vs Flooded Lead Acid Batteries | Good Sam Community

pnichols
Explorer II
Jul 31, 2014
MEXICOWANDERER wrote:
Battery age claims by itself is almost worthless. It must be factored against total kWh transacted during it's lifetime.

Exactly!!!

That's why my 12-14 year old special 92AH Ultima cylndrical cell Yellow Top AGM 12V battery is still "good" ... I don't use it much. (... but charge it maybe once a year)

I suppose Ma Bell's relay station standby wet cells did the same. I wonder if those huge wet cell jugs in the basement of Scotty's Castle in Death Valley are still "good". :h
MEXICOWANDERER
Explorer
Jul 29, 2014
Valid if maintenance charging is eliminated out of the equation...

Calcium/calcium batteries have a yet even lower time discharge degradation yet they make for a horrible cyclable accumulator
Wayne_Dohnal
Explorer
Jul 29, 2014
Battery age claims by itself is almost worthless. It must be factored against total kWh transacted during it's lifetime.
From that I'd assume that the comparatively low self discharge rate of AGMs would in many situations give them a significant longer lifetime.
MEXICOWANDERER
Explorer
Jul 29, 2014
Battery age claims by itself is almost worthless. It must be factored against total kWh transacted during it's lifetime.
VintageRacer
Explorer
Jul 29, 2014
I've been using AGM's in various things since around 2005 and I haven't replaced one yet for plain old wearing out and not holding a charge reasons.

Brian
svjim
Explorer
Jul 29, 2014
dons2346 wrote:
Golden_HVAC wrote:
................AGM batteries will not last as long, say 4 years or so, if you keep them full most of the time, you might get one more year.long service life............

Wow! Good thing my Lifeline 8D AGMs haven't read this. They were installed in January 2004 so I guess they should have been dead and buried long ago

Yea, I had my two 6 volt Lifeline AGMs for 11 years. Hooked up to a good solar system and controller and they put the Ever Ready Bunny to shame.
MEXICOWANDERER
Explorer
Jul 28, 2014
Wanna pick door #1 or door #3

It's all about compromises. Pluses and minuses. Does the product suit YOUR needs (not someone else's).

Funny. The last group 31 (most respected brand) AGM I capacity tested averaged out to 92% capacity at the 20 hour rate. Ten tests, with innumerable checks, counterchecks and substitutions of testing apparatus to eliminate chances of induced error. The accumulator was cycled ten times before the test began.

Some AGM OEM's may be rather optimistic in their blather about ampere hour capacity.
christopherglen
Explorer
Jul 27, 2014
Just remember, don't compare cheap AGM's against high end flooded..
mperkins52
Explorer
Jul 27, 2014
2000 watts - Xantrex Freedom 20 ..... thought about the watering system when I saw one at Camping World .... seemed a little pricey, but my back may now be willing to spend the money .... how does this system keep from over filling the batteries? a float valve that closes? I often wonder if just riding up the not very well maintained road to my house just splashes the water through the breather caps (smiley face) ....

I will look at the AGM's around (Sam's, Batteries and Bulbs, etc. and see at what cost my back will not be offended) ..... love the talk .... thanks for all the recommendations ....
wa8yxm
Explorer III
Jul 27, 2014
I will also say there is nothing wrong with AGM. AGM's are used in battery back up devices like UPS units used in offices across the country where they are maintained at 100% nearly all the time,

Now that said.. I'm not sold on AGM's being the do all and end All, I think flooded wet cells are better, but, frankly there is nothing wrong with AGMs save for one small item (The item is small, the number on it is not,, the price tag).

They are kind of expensive.

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