On 10/12/05 11:59 ET, Larry Fine said...
Once the batteries are initially charged,
the alternator only needs to be large enough to
supply (replace) power actually used. The only
advantage of extra batteries is for extended engine-off
run time.
You only need an increased recharge capacity if
you feel the need to recharge the batteries faster
than the original charger can.
Yeah, but when he said replace, he didn't say with a larger one. It is a reasonable assumption that he meant that, but maybe not: there are batteries that are just fine with a good fast charge plus a trickle charge, and there are batteries that need to have the charging VOLTAGE as well as current reduced when they near full charge, so those chargers are more sophisticated. And using this type of battery with that type of charger can result in sudden autoremoval of battery. And hearing, if you are nearby.
It has been so long since I have been into the different types of rechargeables that I don't remember which ones need which type of charger, but it is not wise to swap one type of battery for another without checking with the manufacturer to see if the same charging circuit will work for both types.