I brought the batteries into the kitchen to warm up, charged them overnight, then desulphated again at 70F. I got a much better result. They are both close to 100% capacity.
Maine Sail says that the batteries probably did not lose charge for the few weeks they sat in the garage before they were desulphated, so there are two possible reasons that the first desulphation didn't
work:
1. Batteries don't desulphate well below 0*C.
2. The 1/4 cup of distilled
water that I added to each cell just prior to desulphating did not mix well during the desulphation and thus reduced the specific gravity readings I obtained after desulphation. I thought the desulphation would cause mixing, plus I rocked the batteries a bit to facilitate mixing.
What do you think???
Second desulphation data below.
West
Marine Deep Cycle Battery , Fully Charged
Specific Gravity @ 70F
(+) term 1.272 1.278 1.275 1.272 1.281 1.272 (-) term
Average specific gravity = 1.275 = 105% capacity
Starter Battery, Fully Charged
Specific Gravity @ 70F
(+) term 1.253 1.255 1.258 1.258 1.256 1.256 (-) term
Average specific gravity = 1.256 = 91% capacity