General Chemistry rule of thumb: For every 10-C increase in temperature the reaction speed doubles. So, if you drop 10-C, I’d expect the amperage will be about half. There is a specific temperature that the battery CCA is measured at, but I can’t remember what it is.
On my JDM tiny truck that I use to plow with, I installed shore power. I split that into two runs. One goes through a thermostatic switch, which closes and energizes the line at 0-C. The feeds the self adhesive oil pan heaters on the oil pan, transmission, and transfer case, plus a battery heating pad. The other line is on anytime the truck is plugged in, and connects to a battery tender, to keep the battery topped off. That solved all the cold start issues i as having with it.
Next summer, I’ll do something similar to the tractor. Probably still plow with the tiny truck, and use the FEL on the tractor to pick up snow from piles by the driveway, and move it so I have somewhere near the driveway to push it to.
Tip on running 120V power on vehicles. Buy a roll of hollow stainless steel grounding strap, and use it to sheath all the cable runs. Ground it to the frame at both ends, and connect the Equipment Grounding Conductor from the power feed to the frame of the tractor. Run the power through a GFI breaker. If you get a short the GFI will trip. You could use EMT, instead of the braided ground strap. But, then you would need to put a bunch of complex bends in the stiff tubing. The ground strap just runs where you need it to, and clips in with cable ties.
ding beep
