We used 8d batteries in the old triple nickle (555) diesels. It was-19 degrees last week in parts of Ohio. If I was still working I would have come home with some good batteries last week. Our head wrench would always just swap in two new batteries to keep the equipment ready to run. I would hit the shop as soon as I could and haul off the junk batteries. Alittle charging and they would not freeze all winter and would be ready for whatever in the spring. Ran a dead 8d for 10 years.