How Cold is Too Cold for a Car Battery?

The Amundsen-Scott South Pole Station in Antarctica is not the coldest place on earth, but it is the second-coldest and it's not far from the number one. The coldest temperature ever recorded there was -117°F and even a warm summer day is unlikely to see temperatures much above 10°F. When someone asks how cold is too cold for a car battery, the answer can probably be found here. 

OPTIMA YELLOWTOP and BLUETOP batteries are protected from freezing down to -30°F (except the 34M BLUETOP) and OPTIMA REDTOP (and the 34M BLUETOP) batteries are protected from freezing down to -50°F, when they are fully-charged. However, the more discharged any lead-acid battery is, the more vulnerable it is to damage from extremely cold temperatures. That makes it critically important that you keep your batteries fully-charged to at least 12.6 volts whenever possible (YELLOWTOPs & BLUETOPs are fully-charged at about 13.0-13.2 volts).

Those claims might be a bit conservative, but if a company makes any claims about their products, they need to be prepared for someone to put them to the test. That brings us to Captain Jack Sharp, who worked as the shop foreman at the Amundsen-Scott South Pole Station in Antarctica. Captain Jack knows a thing or two about cold weather, so when a cold snap hits the lower-48 United States and freezing temperatures creep into Florida, Captain Jack just chuckles at the hysteria. This is Captain Jack's OPTIMA BLUETOP story:

This happened in 2009, when I was doing a winter over. We have around ten 40,000 BTU heaters we use to heat just about anything up outside that might need it. All but four were put away for winter out in the equipment area. I brought one in after sitting out in 80-100 below zero weather for eight months. It was packed with snow, so I let it thaw out for three days.

When I went to install a battery in it, there was already one still in it from when it was put away- an OPTIMA BLUETOP. I would have bet $100 it wouldn't start the diesel engine. I pressed the button for the glow plugs for about 30 seconds, hit the starter button. Low and behold, it started the engine. I did nothing to the battery, never even touched it or the cables to it. I just wanted to see if it would start. I was in disbelief. From then on, I have nothing bad to say bad about OPTIMA Batteries. They're #1 in my book!