Join Date: Feb 2007
Location: my mother's basement
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[QUOTE=camaraderie;216282]Hoffa...sorry but that is not right. Wet cell batteries can only take about MAXIMUM of 20% of capacity during bulk charging which means that a 60amp altenator is fine for a 300ah bank.
Even with charging system loss...fully charging is simply a matter of time. Incomplete charging can happen with ANY size charger and is definitely a problem if you don't monitor what is happening in your charging routine.
I'll have to double-check on that 20% figure of yours, but the problem is losses due to poor design (which is standard), lots of crummy connections (ditto), and recharge time. It would be easy to draw down the batteries each night and unless you are going to run your diesel all day, a smaller alternator won't have enough fart to fully charge the batteries, especially if it's a good day for sailing you won't run the engine enough. The 30% rule is supposed to be a ballpark for choosing alternators.