-15? Wow. Keep those batteries up!

Interesting story and more research is needed, but I just recently replaced my batteries under warranty. I received them and popped them on a 1.3 amp BatteryMinder trickle charger/desulphating smart charger for three days. Took them off the charger at 5pm. It was 0 degrees. Next morning was -10 and the Schumacher charger showed the batteries at only a 70% charge!

What I needed to have done is popped a volt meter on them to see what the ol' meter read, but I will do that next.

Upshot: maybe it is just a limitation of the Schumacher, but for a battery to show that low that quickly is amazing. Cold = unhappy batteries. Unhappy batteries = unhappy FICM.