AGM Battery Life Expectancy

[Beltzington]

Has anyone else noticed these new batteries seem to fail much more frequently than the old lead acid? Allot of information on the web but based on my personal experience it seems like I am replacing at least one every year in one of my toys. It seems they do not like being fully discharged and recharged as often, or maybe time just passes faster as I have gotten older.

 

[Bigkrank]

I have some 12 years old still working fine. I guess after Optima moved production to Mexico the quality and life took a dive. Not sure I would buy a another new one. I had 17 of them around here at one time. Only ever replaced 2 and they had 9 years on them.

 

[The Fred]

One must be very careful charging them compared to flooded lead acid batteries.

Voltage must be maintained and nothing above mid 14 volts.

Use a maintainer that controls voltage to 14.4 and not over or else you can fry the things. An old style battery charger that keeps tabs on amps does not keep tabs on voltage therefore we see voltage rise over 16 volts when using one of these old dinosaur chargers. Best to throw them away and find one that controls volts as the amps take care of themselves when voltage is correct.

Good luck, Fred

 

[Beltzington]

One must be very careful charging them compared to flooded lead acid batteries.

Voltage must be maintained and nothing above mid 14 volts.

Use a maintainer that controls voltage to 14.4 and not over or else you can fry the things. An old style battery charger that keeps tabs on amps does not keep tabs on voltage therefore we see voltage rise over 16 volts when using one of these old dinosaur chargers. Best to throw them away and find one that controls volts as the amps take care of themselves when voltage is correct.

Good luck, Fred

Thanks, good point, my problem has only been with the PWC and motorcycle sized batteries, they never seem to last more than 2-years, I too have Blue marine optima's that have lasted well over 6-years. I thought I had a modern charger approved for AGM batteries and the manufacturer BatteyMINDer owners manual says it is approved for AGM but I found an article were they seemed to indicate their new "AGM" model was much better. Not sure if they just want to sell their new chargers or they found some issues with the old ones. I may just go back to the sealed gel batteries for the PWC I never had any issues with them.

 

[xring100]

AGM batteries do not like to be deep cycled do it once and it takes a special charger to recover them. We have a several thousand dollar machine at work to do it optima now offeres a charger for $200 Optima Digital 1200 12V Performance Battery Charger and Maintainer Amazon.com: Optima Digital 12 12V Performance Battery Charger and Maintainer: Automotive
This will bring them back to life.

AGM batteries actually have a higher static voltage than lead acid and do infact take higher voltage to charge. In colder temps Ive seen OEM car manufacturers pushing 15.5 volts or just over to charge them. As temperature rises the voltage drops. See the attached image i highlighted the bottom showing that the battery minder uses a 0.6 v higher float and charging voltage.

Automotive OEMs are switching to these more expensive batteries because they handle the high heat of Arizona or other warm states far better. They have helped lower battery warranty in these states. They are also superior in vibration handling. Their Achilles heel is that they do not like to be discharged Best to keep them on a maintainer of the sit dormant for lengths of time.

Definetly get a multi stage smart charger prefferably one that is temperaturecompensated

 

[Ford850]

If AGMs have to be on a maintainer to keep them healthy, doesn't that sort of defeat their advantage of lasting longer? I keep my lead acid batteries on a regular battery minder rotation now, and the life of them is much better too. Does the extra cost justify the AGMs?

 

[pmsmechanic]

So my first response to this article was "What's an AGM battery". Instead of asking I decided to look it up and came across this article. How To Charge an AGM Battery - Hot Rod Magazine. Well worth the read.

 

[Beltzington]

So my first response to this article was "What's an AGM battery". Instead of asking I decided to look it up and came across this article. How To Charge an AGM Battery - Hot Rod Magazine. Well worth the read.

Interesting information, wish I had waited a day to buy a new battery Optima's recommendation to use a "good" battery to trick the charger into charging would have likely resolved my issue as the battery voltage was below 6VDC.

Considering this discussion and further research on my part I believe AGM batteries are fine as long as they used frequently and kept charged. The problem I have been seeing is likely because they have become to discharged from sitting for weeks and sometimes months and the voltage has dropped below what my chargers can handle. Have to wait to test this theory.

One interesting note is the replacement AGM battery I bought only has a 90-day warranty instead of the year warranty of the previous battery from the same manufacturer.

 

[xring100]

Ive tried the slave battery to trick my charger on a 2 year old motorcycle battery with no luck. Charger started charging but never recovered the discharged battery

 

[The Fred]

I replace twice as many BMW AGM batteries as I do flooded lead acid, they just don't last and when I do replace them it is usually with flooded lead acid and retrofit software for the proper charge rate.

I won't buy one for my own use, Fred