My one way drive to work is 30 miles, sometime 32 miles. L2 at work! With my 10-bar leaf I would have thought that I was future-proofed for a few years, well the polar vortex taught me otherwise. those two really cold days In the morning it was at zero temperature bars, with -10 to -20F in a garage with a L2 charge finishing right at the departure time. When the temps are 20F out I have 2 battery temp bars for the same conditions. And with even a little headwind I was getting LBC ½ mile from work. The lowest I ever got was 3miles on the GOM pulling in. no heat, no defrost. Only a 12v fan defroster and heated blanket.
The solution as I saw it, short of buying a real car and not a darn golf cart with doors, was to reduce the power draw of the battery heaters by preheating the traction pack, and holding that heat in for ½ hour. So I bought 2x 150w silicone pad heaters and one sheet of foil faced EPS foam board, foam safe construction adhesive and waterproof foil tape. Total $65 spent here.
Inspired by this post (viewtopic.php?t=15673) I installed the heaters on the bottom of the clean battery shell and covered them over with the butyl faced foil tape. Then I cut the foam board to 32” width and various lengths to fit close to the battery. Then I put the same waterproof tape around the edges of the foam board so it would not soak up water and get moldy. to install them I used the glue on them making a perimeter all the way around with the caulk to seal out air.
The electrical situation is not fully fleshed out yet, I have a metal LB box to install and will terminate the heaters to a extension cord inside that box and run the plug up to the motor compartment, until then I have the wires zip tied up to the rocker panel.
I know that this will not work for southern cars, and cars the DCQC 3x times a day, but a L2 only car with mild Ohio weather I figure I can leave these on all year round. The foil facing pointing down will reject heat from hot parking lots and could even, perhaps, keep the battery cooler than if no insulation was there in the summer, the tarmac road surface can be 130F, but the air is only briefly over 100F at 2pm in a summer heat wave. And if my guess is wrong and it’s at 8+ temp bars all the time, I’ll pull it off.
I also sprayed marine rust proofer on the rocker panels, anything metal, and the edges of the battery pack, its like cosmoline, goes on runny and turns into a wax coating.
THE RESULTS, with the heaters running for 90 minutes before departure, the temp readout is at 4 bars, when it normally would be 2 bars. The two mornings that have been below 20F this week to try this idea out, suggest that it works, seemingly adding GOM miles compared to what I am used to. Today I rolled in with 15 miles on the GOM, a 5-10 mile GOM improvement. But its hard to say for sure, since the wind was not so bad today, only a 10mph head wind, but I think 5 miles extra is a reasonable conclusion. time will tell.
Heating pads installed
Insulation cut and dimensions drawn on
front half ready for the cover to be on
Rear half ready for the cover to be on: