AGM Battery Question ....W

[Ramblinman]

I let my AGM batter go dead. 10.5 V. First time in 4 years. I feel like a dork.

Questions:

1. Will there be any noticeable damage to the battery? I ask because I am just about to leave for 10 day trip and I am wondering if I need a new one.

2. I have a solar panel that clips directly to the battery ... its an all in one deal in which the controller is built in to the panel ... is this sufficient to charge an AGM Battery? I ask as it seems as though, doing research on the net that AGM Batteries require a specific type of charger.

3. What is the most healthy way to charge a completely dead AGM battery.

Thanks

 

[brianjwilson]

What brand? They all have different voltages and time periods for optimum charging and absorption. For example Odyssey sells an "ultimizer" charger speicifically for theirs. Look up the manufacturers recommended guidelines for best results.

 

[Ramblinman]

Will do. It a deka from FWC.

 

[fuzzymarindave]

I would suggest you go to an industrial battery supplier and let them charge it overnight. Household charger is not likely to bring it back.

 

[brianjwilson]

I would suggest you go to an industrial battery supplier and let them charge it overnight. Household charger is not likely to bring it back.

Agreed, but it needs to be charged differently than some flooded batteries.

Here is an awful manual from 2007 I found. The deka website is terrible.

http://www.unavco.org/projects/project-support/polar/support/deka_battery_handbook_2007.pdf

 

[Wandering Sagebrush]

On my Zamp controller (Airstream) they recommend setting it to 14.7 volts for AGM, and 14.4 volts for flooded. Just a switch setting.

 

[PaulT]

If yo don't have a good smart charger, now might be a good time to acquire one. Something like the
NOCO Genius g7200
http://www.amazon.com/NOCO-G7200-UltraSafe-Battery-Charger/dp/B004LWTHP2

Or

the CTEK 7002
http://www.amazon.com/CTEK-56-353-12-Volt-Battery-Charger/dp/B000FRLO9Y/ref=sr_1_1?ie=UTF8&qid=1430495901&sr=8-1&keywords=ctek+7002+battery+charger

These work well and should recover your battery if it is otherwise in good condition. I chose the NOCO because it was offered at a good price at the PDX Sportsman show a few years back. I use it daily to recharge a wet cell battery used for an electric fence, and regularly for my AGM batteries used for my ham radio activities which range from 12ah to 100ah.

Just follow instructions to configure for AGM.

Good luck on recovering your battery and don't let it sit discharged very long.
Paul

 

[Ramblinman]

Thx for the replies!

 

[Advmoto18]

I use the Optima Digital 1200 (~$190 on the street). But, the 400 is just as good, not as many features. The 400 will set you back about $100.

AGM's require a "smart" (digital interface) charger to properly re-charge and to enhance service life.

If you don't want to purchase a charger, most automotive parts suppliers (NAPA, Advance Auto Parts, Pep Boys, etc.) have chargers suitable for restoring your AGM battery. However, if the battery is 4 years old, you may not have much useful service life remaining after taking it down to 10.5V. You can have the shop restore the battery to capacity, then initiate a constant 25A draw and time the discharge to 10.5V. Compare the time to that of a new battery's (same model) reserve capacity and it will give you an idea if you should spend the coin on a new battery or continue to use the 4 year old one. Just be aware that the new battery reserve capacity specification is based on 80'F during the 25A draw.

 

[Old Crow]

Just wanted to tie this video to this thread. It shows a little trick you may want to try if the charger won't charge....

My comments-

I had to go through the fool-the-charger procedure in 2012 on my van's Optima YellowTop. My Schumacher 10-amp charger has an AGM-specific setting but wouldn't charge the battery above 7 volts after hours of connection. It didn't show an error or bad-battery status or anything.... voltage just never rose above 7 volts.

Optima tech support clued me in to the parallel-battery thing and that did indeed trick the charger into working. I'm still using that battery and in fact killed it dead and recovered it again last year (I really shouldn't have disabled the headlights-left-on switch, should I?), this time just on the van's alternator.

I also note that later in the video, the guy uses a CTEK 7002 like Paul T linked to in post #7.

-OC