12 volt in parallel - SailNet Community
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post #1 of 3 Old 07-12-2013 Thread Starter
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12 volt in parallel

Hi Everyone,

I have two 12 volt batteries in parallel on bank 2 and one starting battery on bank 1 on my Catalina 30. The starting battery is new. The two battery's on the house bank are from PO and not in the best shape.

One battery is a 70 amp hour under the navigation table and the other is a big 150 ish (cant recall) under the cockpit birth.

My question is when I replace them is it ok to mix batteries with different amp hours like that in parallel? I have found mixed information?

I may also go 6 volt in series but for this post I am just looking at my 12 volt options.
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post #2 of 3 Old 07-12-2013
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Re: 12 volt in parallel

Batteries in a bank should be the same size - you risk overcharging/undercharging and premature 'death' of the batteries.

Lessons learned are opportunities earned.
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post #3 of 3 Old 07-13-2013
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Please buy nigel calders book 'boatowners mechanical and electrical manual'. Excellent information on everything you need to know in fairly easy to digest terms
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