While I generally agree with what Chief, Maine
, and Gord said, there's another way to look at it.
Any small diesel is capable of handling an 80-amp alternator at anchor
, and if you plan to charge your batteries with the diesel at anchor
, that's probably a good bet. It would load the diesel nicely and charge the battery
bank faster, etc., etc.
There are several ways to limit the output of the alternator, and thus the load on the diesel:
- a smart regulator
, like the MC-612 or 614 can be programmed to de-rate the alternator to any desired percentage of it's maximum output;
- these regulators also can be fitted with a simple ON-OFF switch which cuts the alternator output in half -- that would just about equal the output of your existing alternator -- whenever desired.
Remember, too, that as batteries charge their charge acceptance rate drops, so the alternator puts out less current and the load on the engine drops.
Finally, it takes just over one shaft horsepower
per ton to drive a displacement
boat to hull speed