I was charging at 15.6 -16v, and my resting ocv's were a little lower than usual, so I thought maybe the voltage was a little high, even for the cold temps. (I find in the warm weather, too high a voltage results in lower ocv's). So I thought maybe once the batteries were warmed up from charging, the voltage didn't need to be as high. Well the result was the ocv plummeted. So higher voltages are definitely needed.
This past Thursday, at 12F, ocv was 12.57v. After warming the cabinet under the bank with a microfurnace, and warming the battery cabinet with a hair blower to 44F, ocv rose to 12.63v.
I have tried to find information about the effect of cold on resting voltages, but cannot find anything. There is, of course, no shortage of info about temp compensating charge voltages and SG readings, and how cold slows self discharge, but nothing about resting ocv. But it does appear warming the bank will help raise resting voltage. And of course it will help with battery acceptance.
If your buddy's charger is preset too low, he will definitely have to bring the battery in from the cold... especially this weekend.
