Jere Lull wrote:

In rough numbers, to effectively consume that much power, the boat would
have at least 500 AH capacity. My 55 amp charger rarely runs as high as
20 amps for a few minutes on our 250 AH system. Even the smart charger
doesn't stay that high for much longer.

That's not my experience. I have 4 Trojan 6 Volts, for about 450 Amp
Hours. My charge rate starts at over 100 Amps and spends a lot of
time (close to an hour) over 80. When I get over 80% full the rate
drops fairly fast and I shut it down below before it goes below 50
Amps. I'd rather run 5 minutes tomorrow than 10 today.

If you're only charging at 20 Amps then either you're not very
discharged, or the alternator or regulator is not pushing very hard.


And it can only be used on the deck unless it's set up to be sparkless
and the exhaust can be piped away from the interior, which eliminates
much of the cruising crowd.

Certainly if its automatic, a number of precautions must be taken. I
would use a small genset on deck rather than run the engine, if it
could actually charge at 80 Amps.