Well for fun I have taken a quick video of the block of ice that split with the battery inside. Cell still discharges and quite frankly if it still discharges it should be fine to take a charge too. That is my thinking and if at zero degrees it still works I am going to just bust any cold battery issue wide open. So far so good. New bucket tomorrow and will refreeze the water with the battery. Should do the charge test on Wed. Keeping the cell frozen until then.