Tom, battery voltage should be tested after resting for an hour or more after charging. Your charging voltage sounds about in the right range, but you are measuring the voltage coming out of the charging source, not the battery. 13.2 V is about minimum voltage to overcome internal resistance and actually charge the battery. A healthy charged battery will test at around 12.65+ after resting for 12 hours. Each battery will have to be checked individually, so they should not be interconnected for that. Just remove the black wire for testing, you don't have to totally strip them. In addition, get a *good* battery hydrometer and check each cell for the right specific gravity. My battery guys recommend the EZ Red unit, and I agree. (http://www.ezred.com/product/battery-hydrometer/) I had THREE cheap hydrometers give me similar readings that were nowhere near reality, and that cost me a couple of weeks of anxiety while cruising, and a lot of work taking the three Group 31's out and having them tested for real with a pro analyzer, then reinstalling them. West Marine stores generally have a load-testing type of analyzer if you drag the batteries in to the store, but I'd advise taking them to a real battery shop if you're going to that amount of labour. Good luck.
Jim Watts Paradigm Shift C&C 35 Mk III Victoria, BC On 16 July 2017 at 15:37, Tom Buscaglia via CnC-List <cnc-list@cnc-list.com> wrote: > I stressed out m house bank pretty bad by leaving the frig on and the D.C. > On, but the shore power, and this the charger, came lose on the boat due t > my sloppy connecting. > > It was discovered after 3 days or so. I am concerned that the batteries > may be damaged beyond use...just like the set of house batteries these > replaced, after two full days at anchor with the frig runningh. > > Very lagged with them all still wired into the boat are around 12.5. 13.2 > when the engine is running and 13.7 with the charger on. > > Some questions for the list's cumulative wisdom... > > Do I need to disconnect the battery to accurately assess its health? > > Are these voltages in an appropriate rage? > > thx > > Tom Buscaglia > S/V Alera > 1990 C&C 37+/40 > Vashon WA > P 206.463.9200 <(206)%20463-9200> > C 305.409.3660 <(305)%20409-3660> > > > _______________________________________________ > > This list is supported by the generous donations of our members. If you > wish to make a contribution to offset our costs, please go to: > https://www.paypal.me/stumurray > > All Contributions are greatly appreciated! > >
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