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  #11  
Old 12-25-2012
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Re: How do I know how much I need?

Now I better understand. I, perhaps, was very fortunate, 'cuz our boat has a built-in battery box, but it only designed for two batteries, hardly a good start for a reasonable battery bank(s)!, but that was the "thinking" of the boat builder at the time (mid-80s). My PO, though, added a flat platform in another storage area on the boat, so I have almost 400 ah with three Grp 31s, plus a separate smaller reserve bank. Other than having to wire a larger output alternator direct to the house bank (avoiding the switch), not much, actually nothing, needed to be changed.

You're certainly right about the kinds of "issues" facing a lot of skippers.

Thanks for your clarification.
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Old 12-25-2012
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Re: How do I know how much I need?

Thank you for posting expected output for solar panels along the east coast. ? Any thoughts on what can be expected from two D400s during the summer and fall in New England.
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Old 12-26-2012
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Re: How do I know how much I need?

When I read about this I found that people estimated solar output a lot of different ways.

Some take the total watts and divide by 3 or 4 to estimate 12V amp hours per day.

Some multiply the max output by 4 or 5 and use that as an estimate of 12V Amp hours per day.

If those estimates sounds loose, that is because...well, it depends on so much. I would use all 4 estimates and make a min-max window and be fairly confident your own experience will fall somewhere in between.
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Old 01-31-2013
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Re: How do I know how much I need?

Stu,
Do I understand your basic battery wiring system recommendations (same as those set forth in Mainsail's instructional on the same topic (both of which have been very informative to this electrical neophite)...to be that the reconfiguring of the classic battery switch wiring to function as a "use" switch instead of a directing charge switch is helpful in eliminating human error damage to your battery system, ie. dead batteries or blown diodes, but if you forget to either defuse or otherwise disconnect the new alternator to battery wire before working on the engine, that human error may kill you?
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Old 01-31-2013
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Re: How do I know how much I need?

Stu,
See my last post to this thread. Thx.
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