The reason for the 800 amp hour bank is that I will have two large
computers, a 3000 watt inverter, SSB radio and a rather powerful
autopilot. All of which will eat a fair number of amps. I have
estimated my daily energy budget underway to be between 180 and about
225 amp hours.

Two other factors determined the bank size. The first is that deep
cycle batteries should never ne discharged below 50% to preserve their
useful life. That limits my usable power to 400 amps. The second is
that I would like to keep engine time to a minimum. All the systems
that use engine power, charging, watermaking and refrigeration are
designed to restore themselves in one hour of engine time per day.

Up to about 75-80% charge, deep cycle batteries can accept a charge
current of up to 25% of their capacity. As they approach full charge
the rate has to be reduced substantially. That sets an upper limit for
daily charging at about 80%. The result is a net usable capacity of 30%
or about 240 amp hours.

As I said, You set the tone of the conversation.


--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
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