I have a small boat (MacGregor 26M) with a Honda 50 outboard engine.

Needless to say I have a battery for it... plus two house
batteries. I also have a throw switch (or whatever it is called)
allowing me to use just the Honda battery... or the two house
batteries... or all... for my DC electrical needs.

When motoring with the Honda is it okay to use the "or all"
mode to charge the aformentioned batteries... or would it put
a strain on it's alternator.

So far I have been using the "one battery" mode (for the Honda)
when operating the outboard engine. I have a marine charger that
I use for the house batteries when hooked up to AC shore power.

Since I motor quite a bit... I would like the option to charge all
batteries providing it isn't a strain on the Honda alternator.

Thanks for your help..

Best regards

Bill