Originally Posted by mitiempo
I do not know of any battery
that doesn't need to be fully charged as often as possible. This is even worse with AGM
batteries than with flooded. That is why long term cruisers use solar and/or wind
generators to top the batteries up. Engine charging
won't get you past 80% to 85% SOC without many hours of engine time.
Good traction batteries like the Rolls/Surrette can be 15 year batteries if properly treated.
Sorry, I wasn't clear. I know all batteries need to be fully recharged, including running them through the full absorption cycle. The issue with the big Rolls is that it takes much longer the get them through the absorption phase than batteries like Trojans. Apparently it's a side effect of the heavier plates in the Rolls.
I've got mine where they can be recharged via a generator
with 6KW charger
in about 8 hours. It takes 3-4 hrs to get them through bulk, then 4-5 for absorption. But that's charging at 60V (it's a 48V bank) bulk/absorb. That's equivalent to charging a 24V bank at 30V. It's a really hot charge voltage and is the only way to get them through charge in a reasonable time. All this was arrived at after working with Rolls for about a year. Initially they wanted some ridiculous absorb time like 8-12 hrs - basically longer than the sun shines, and longer than anyone would be willing to run a generator
or main engine. It works, but they consume a lot of water
- about 8-10 gal every 6 months for the bank.
I had Trojan L16s before and they would go through the absorption phase in about 2hrs.
The "tail" of the charge cycle (absorption phase) is the Achilles heal of battery charging for cruisers, and Rolls batteries have a much longer tail than other batteries.