Re: [A/S] What are AGM batteries?

["Jim Dunmyer" <jdunmyer@xxxxxxxxxxx>]

John,
 There's a couple of reasons that the GC batteries outlast the
"RV/Marine/Deep Cycle" units, especially when paralleled for more capacity:

1. There's no chance for "circulating currents" that come about due to the
[inevitable] inequalities in the cells of the 2 batteries.

2. GC batteries are true Deep Cycle design, with heavy plates and lots of
electrolyte capacity. They're meant to be discharged deeply, day after day.
The more-common 12-volt batteries aren't much more than warmed-over starting
batteries. (which won't last long at all in this sort of application)

As a side benefit, a GC battery is rated at 200+ AH (usually 210-225) and
will actually provide that much power. The RV/Marine jobs are rated at 105
AH/each (in the Group 27 size), but will only provide about 90 AH; that's a
total of 180 AH when they're in parallel. So, you have more capacity (more
hours of TV when boondocking) and if the daily usage is equal, the GCs are
being discharged less than the others, making for longer life.

If they'd fit under the couch where my 12-volt Group 24s live, I'd have a
pair of GC batteries with HydroCaps. But, with our meager usage and solar
panels to recharge them every day, we get very good service anyway. We've
stayed in one place as long as 3 weeks w/o hookups and have never come close
to running out of power.

                                                             <<Jim>>