This topic is not RV related but there is more battery expertise here than anywhere else I know of. Mostly over my head :)I have this AGM battery in my Seadeoo. I used this maintainer on my wet cells, it worked great for them.The AGM says it needs an "automatic temperature sensing voltage-regulated charger", such as, I suppose, this..I disconnect the batery for storage, but even so I'm down to about 12.3 volts.So, the questions is, can I use my current maintainer with this battery without shortening its life, or do I need to shell out for a new mantainer?Thanks in advance.

The battery "purists" will hate this answer..........ANY fully automatic maintainer is better than none.And disconnecting/removing the battery probably does nothing productive.In order to break even with buying a $100 charger over the lifetime of a 7 year battery, it would need to roughly double the lifespan......compared to the charger you already have.Not likely that it will make anywhere near that much difference.If it gets you an extra two years, it won't pay for itself until your 4th replacement battery......or 28 years roughly.P.S. How many seasons has your present battery gone down to 12.3 and been left sitting that way ??

You can "roll the dice" and use the existing maintainer. You can "have a throw" at using a regular charger and manually monitor temperature. Or you buy the recommended equipment. Personally I'd fully charge the battery and then store it. I would not risk a maintainer unless it were specifically for that exact battery. I.E. a charger from duracell.

WRONG! Sam SpadeYou are quite correct IMHO :)I just do not like seeing more than 13.6 volts on an AGM battery at 70F at 80F the 13.6 would be too much. The battery will not live as long. Here at 95F I have been dropping the maintain to 13.1 with a twist of my wrist. When all is said and done in Michoacan the 10-turn pot will be over my head and volt display off to the side.I would hate to think any maimtainer can't do these numbers.

12.3 ????? Isn't that about dead ?? If disconnected I'd say that battery is toast ?I have 3 of those typical batteries in my electric 36v bikeAnd I have 2 of the AGM electric chair 35 AH in my B&D 24v lawn mower, and they are ALL charged/maintained w/ a Battery Tender JR, and have been for many years, and work great.You do not need a temp regulated charger,....except maybe in very warm weather. But mine do just fine in 100 degrees.

I would just use the maintainer that you have. Do not let the battery sit one more minute at 12.3

AGMs & Maintainers | Good Sam Community

37 Replies

Tin_Pusher
Explorer II
Aug 24, 2016
On the maintainer 15 hrs yesterday, after resting overnite getting 12.69 V, didn't really gain that much. But good enough for now I guess.

Almot, you'd lose that bet. Manual doesn't say much of anything at all, just a bunch of cautions and warnings. If it had a real manual maybe I wouldn't have to fish around on a forum like this for information :)
Almot
Explorer III
Aug 23, 2016
pianotuna wrote:
Fully charge; disconnect; leave in place; repeat in 3 months.

x2.
I bet the manual for this Duracell says that when fully charged, it will stay above 60% for 6 months at 90F. Slow self-discharge is one of the reasons why people buy AGM.

Shouldn't be a problem for 3 months, unless they damaged it already.
Tin_Pusher
Explorer II
Aug 23, 2016
pianotuna, went from 12.3x to 12.6x (didn't pay much attention the 1/100). Will post in the AM, after todays charge, maybe 15 hrs.
pianotuna
Nomad III
Aug 23, 2016
Tin,

What was the voltage after charging for 8 hours?
time2roll
Nomad
Aug 23, 2016
The battery is just 10 ah and says limit charge to 14 volts.
How fast must it go?
MEXICOWANDERER
Explorer
Aug 23, 2016
Like trying to inflate a 16" tire with your lips. Too low of charge rate will damage an AGM baattery.
time2roll
Nomad
Aug 23, 2016
Battery MINDer should just be left on continuous. No harm unless the battery is left out in the sun.
Tin_Pusher
Explorer II
Aug 23, 2016
OK, update: Connected to the maintainer for 8 hrs yesterday, took the battery off charge, set overnite. This morning voltage was 12.6 (from 12.3). Battery never got even slightly warm. So far, so good.

Back on charge, check it again tomorrow :)
pianotuna
Nomad III
Aug 23, 2016
Fully charge; disconnect; leave in place; repeat in 3 months.
wa8yxm
Explorer III
Aug 23, 2016
Sam Spade wrote:
The battery "purists" will hate this answer..........

ANY fully automatic maintainer is better than none.
And disconnecting/removing the battery probably does nothing productive.

Well then.. I guess I must not be a "Purists" for I agree :)

(by the way, I disagree with the purists on several issues).

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AGMs & Maintainers

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