[puddleglum]

Originally Posted by jakobnev

If you can't charge the car where it is parked, then you need a portable way of transporting charge to your car.

Here is what I went with:
I just connected it to the car through both filaments of a dual filament headlight bulb, but a DC-DC converter would be better.

I did something similar with a e-bike battery this winter and went through a pair of cheap dc-dc converters off of eBay. It works pretty good but it could use a bigger converter. Disconnects easily to take in for charging. LED lights help as well.