My F350 has 2 batteries. Big batteries. It takes a lot of power to turn over a 7.3L diesel engine. Since I bought my Jetta for commuting the truck doesn’t get driven as much.
Our horse trailer has been in the shop for 3+ weeks getting service, repairs, and some custom work I wanted done to make it a little nicer. Tomorrow after work I will pick it up. This will be the second time it has been driven this month. So, since it usually needs to be jumped to crank after a week or two in these temps, I decided to check tonight instead of before work. It was dead. As in less than 8V in the battery. And then the jumper cables melted the contacts in the cable clamps trying to recharge the truck.
Time for new heavier cables. And probably 2 new batteries. I wish batteries would last more than 18 months in this truck.
You probably have some amount of parasitic load pulling the batteries down. with two large batteries it would take a month for 200ma load to kill them where a single battery would go dead with an a week. As the reserve capacity of the batteries deplenishes over time the faster the batteries loose there charge. the extreme cold makes matters worse as a weak or dead battery can and will freeze. the frozen battery is susceptible to buckling and shorting them selves from the ice expansion. a fully charged battery will withstand a much lower temperature. testing for a parasitic load is a little complicated with two batteries but not if you know how to do it.
Thanks Karl. That’s what I have been thinking too. I have been diligent about unplugging the gps and cell phone charger, but the cb is wired in and the brake controller is a hassle to unplug. I think the brake controller is the most likely suspect. Past experience has shown that cycling the block heater for about 6 hours a night helps with the problem a lot. I was trying to skip that this winter to reduce electric consumption, but looks like it needs to go back on the timer.