I agree with Nightcrawler on this one.

I was in my local battery shop when someone brought in a huge battery; much larger than a car battery. Just out of interest I asked what it was out of, and I was told it was from a Caterpiller Grader. They use those a lot here in Winnipeg for clearing snow. The guy told me that the grader doesn't just have one of those, but two of them. And, the reason why they have two batteries is because they're often left at construction sites overnight in the winter where there's no electricity available for a block heater. So, they need both batteries to provide the power needed to start their cold engines in the morning.

In fact, my understanding is that in Northern Ontario, they will often collect wood and start a fire under the engine of the graders and bulldozers to warm up the oil in the oil pan in order to start their engines in the mornings in winter. I've never personally seen that being done; I just heard that it is done.