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Old 07-30-2019, 03:19 PM   #13
sbman
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City: San Diego, CA
Vessel Name: Second Chance
Vessel Model: 42' Uniflite Double Cabin
Join Date: Jul 2017
Posts: 828
Quote:
Originally Posted by djmarchand View Post
I think we make too much out of the proper float voltage.

Once a battery is fully charged, ie all of the lead sulfate has been converted to lead and sulfuric acid then a voltage of 12.7-14 volts will keep it stable. On the higher end of that range you will disassociate a little of the electrolyte (boil in the common vernacular) and that will require adding water more frequently. On the lower end of that range you risk leaving lead sulfate in solution which can precipitate out and ultimately short the plates.

So keep your float voltage at about 13.5, check the water regularly- I check mine every 2-3 mo, and err on the high side. As long as you don't let the water level drop below the plates, you will do no harm.

David
For flooded cells, that makes sense. The OP has AGM and should follow the manufacturer's voltage recommendations as closely as possible for the best possible life span.
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