Are AGM batteries really that good?

[belfert]

I bought some second hand deep cycle AGM batteries really cheap about nine months ago.  I figured they might be trashed from sitting in my garage since then since I never got around to putting them in the bus.

Every single one of the batteries shows 12.6 volts or better and they haven't been charged in at least a year!  I am shocked!

Are AGM batteries really that much better at not self discharging?  I absolutely have to get them in the bus now as a series of stupid accidental moves in the fall and an inverter/charger failure caused all of my 6 volt batteries to freeze and split over the winter.

[Sean]

Brian,

Low self-discharge rate is one of the many advantages of AGM over flooded batteries.

-Sean
http://ourodyssey.blogspot.com

[gus]

Brian,

You really can't tell by voltage, you need a load test to tell for sure if they are good.

Probably need to be charged before a load test.

[TomC]

Yes AGM's are that good.  They are sealed, don't gas (unless over voltage charged), can be operated in any position except upside down, don't loose their voltage over time (as you've found out), need no maintenance, and since they don't gas, the terminals never need cleaning since they don't corrode.  I think they are worth the roughly twice in cost of a normal wet battery. Good Luck, TomC