Originally Posted by dkchen
So I have two 8D batteries that are 5 years old at the moment. They are flooded batteries. I've been wanting to go to AGM batteries, but I think I would have to upgrade my whole charging
system to do it. I already had a few big upgrades this year, so I am avoiding that all together.
Looking at finding two 8D batteries on the internet
, I find out the literal insane price to ship those things. So I am now thinking of doing two banks of three Group 31 batteries. (I think that is the correct size?) and try to wire them together.
Anything I should be aware of? Will it work the same?
We have three G31s (300 Ah/bank) in place of two 8Ds (~245 Ah/bank). Works fine. Each G31 is much lighter than a single
Our G31s are Odyssey AGMs; the oldest bank is nearing the end of its 10 season. Shows few signs of deterioration. We are more often at the dock
, batteries are easily and often recharged, what Maine
Sail sometimes calls "UPS" service
. Heavy load when out, even for days or a week or two at a time, but with daily recharging via the genset and then back on the shore charger when we return.
Our old-ish charger manual included directions for charging AGMs. Essentially, use the same settings as for flooded lead-acid. That worked OK with the battery manufacturer's charging recommendations, too.
Not a recommendation, just an observation.
For our oldest bank, when I have to replace, I'm thinking golf cart batteries. Happens I can likely fit 4x GC2s in the same area as our 3x G31s. I'd likely stay with AGMs, but if FLAs could be easily maintained (watered and so forth; access to ours makes that a pain) they'd likely be better bank for the buck.