"Jeff" wrote in message
...
* Paul wrote, On 8/11/2007 12:47 PM:
"Jeff" wrote in message
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Oddly, you're always claiming that charging a 450 Ah bank at 80 or
90 Amps is doing great damage. What I'm doing is reduces that to 50
Amps charging, with 30 Amps to the fridge. Are you claiming that
the fridge, radar, and autopilot must be turned off if the engine is
running and the batteries are not fully charged?

Jeff, it sounds like you are mixing Amps and Amp-hours. I'm sure you
know the difference, but it does make things confusing. For example,
my refrig draws about 5A when running, which it does perhaps 6 hours
a day in the tropics. This gives a 24-hour consumption of 30 Ah (at
12V).


Nope - I meant what I said. My system has "open components" where the
compressor is belt driven by a 1/2 HP motor, rating at 39 Amps DC. For
the "noon to noon" day just finished, I had two runs (evening and
morning) of about half an hour for the fridge and freezer together
drawing 30 Amps, so they were 15 Amp-hours each. These pull down
three holding plates, one in the fridge and two in the freezer. This
morning I forced the freezer to run by itself (there's a solenoid on
the coolant line to the fridge) for and extra 30 minutes at 20 Amps.
The total for the day was 41 Amp-hours.

The reason for forcing the freezer is twofold - first, the thermostat
sometimes sticks "on" so if I'm one board monitoring I just turn it
off and add some time as needed. The other reason was to force it to
run while I was running my small genset.

In warmer climates the runs would be longer (because the cooling water
is warmer) and there might be a third run because of increased heat
loss. The worst case is sitting unattended at the dock because the
boat heats up so much.

Your system seems very efficient. I'm guessing its a BD50 based
system with a small, well insulated box, and good air flow over the
condenser.


The cooling water is warmer? Therein lies the key to you efficiency. I
bet you don't count the amps the circulation pump uses? Some of those
things use up to five amps.

Wilbur Hubbard