Much of your problem is a matter of battery capacity as much as a matter of
charging capacity. I have ~450 Ah of capacity on one bank, a 90 Amp
alternator that never reaches full load, and 200 watts of solar. Even
without the solar I was able to comfortably keep the the fridge running and
the lights on when cruising for ~2 weeks. The half hour to hour of engine
operation to anchor or moore in the evening and the same in the morning was
always enough to keep the batteries charged.
Keep in mind that the battery capacity should be at least 4x of the charge
capacity for flooded lead acid and at least 2x for AGM. So a 400 Ah or 200
Ah respectively for a 100 amp alternator.
S/V Sea Hawk
1989 C&C 37+
On Mon, Feb 12, 2018, 12:55 PM Damian Greene via CnC-List <
> A question for your collective wisdom:
> I am scoping out upgrading my stock 55A alternator to a 100A Balmar, and
> related upgrades to the controls. I had a very productive discussion with
> Rod Collins at Compass Marine (mainesail), and we worked out the details.
> Unfortunately he's booked out through the spring, so this job will wait
> until next winter.
> So thinking then about keeping the batteries charged, and the fridge
> running on our long summer cruise - where we may go for weeks without
> access to shore power, I got wondering about using a portable generator to
> charge the batteries - as an alternative to many hours of running the
> diesel. There are a couple of Hondas that might do the trick 2000 Watt,
> weighing 47#, 1000 Watt weighing 29#.
> Have any of you tried this? What could (would) go wrong if I plugged this
> generator into my inverter, to charge the batteries?
> 1986 Sabre 38 Freefall
> Previously 1984 C&C 34 Ghost
> Bass Harbor, Maine
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Thanks everyone for supporting this list with your contributions. Each and
every one is greatly appreciated. If you want to support the list - use PayPal
to send contribution -- https://www.paypal.me/stumurray