Battery protection in the cold

HPC Revolution, Stealth and similar bike owners - have you created a heated battery cover to help the battery operate in warmer temps to extend the range? Any pics? Advice?

I never felt the need for extra range when it is freezing. My lipos are very low IR and perform pretty good in the coldest days of the winter (-25/-30). I keep the rides short when it is that cold anyway, and I never let the bike sleeping outside. I am more careful providing proper vent during the hot days of the summer.

Yet I know some who are heating their batteries before a ride, especially those who are using cells that are too weak in the cold, and/or those who are leaving their bike parked in the cold. I always recommend building with a battery that can be taken off the bike easily, to bring it inside in very cold or very hot weather, or to save the bike in case of a battery fire.

The battery will often heat itself in the cold, so insulation is the main thing. My worst cold performance was when using a tight metal box to hold not so great lipos. So they would start out from the home ok, then sag like hell after a short ride in the snow chilled them enough.

Another time I had problems was when it was so cold I did not want to ride 15 miles to work in it. Around 15F. So I got the idea to bus the first 6 miles, then ride in 9. On the front of the bus rack, my lifep04 battery got very cold, and barely worked at all. Packing some additional insulation inside the battery box helped a lot in this case.

So the low hanging fruit here is obvious, start warmer if possible, and then just some insulation will help after that. Never had a bit of trouble with cold when using a padded triangle battery bag, it was insulated enough. That bag was a bit too insulated in hottest summer though, so I would ride with it half unzipped then, and try not to pull max amps.

Anything can be used to insulate a battery, including the crudest wrapping with packing foam and tape. A bike like the stealth could be covered with neoprene cut from an old wetsuit from a thrift store, or just cut a quilt to make a quickly attached coozie for the battery area. It need not be perfect, just needs to stay on when riding.

Starting out warm works best by brining the battery inside when its cold, but that requres a safe place to put it. Dont burn your house or garage down like I did. (garage battery fire) If you need to heat a battery, the ideal thing for it is a reptile heater. Little warm pad that goes under a reptiles aquarium cage. Its waterproofed. Second best, just a regular heating pad from the pharmacy.

For what its worth, I was heating up my battery before riding and it really helped my performance. I wasn't able to easily remove the battery so I just used a 1500W ceramic space heater to heat the battery up about 1 hour before riding in my garage. This was when temperature were 0C to 10C or 32F to 50F outside. My em3ev battery has a temp sensor, and it was reading 25C to 35C after being heated and would maintain that temperature after my short commute (amount 2kw cont. 5kw peak). I have since doubled my battery capacity but I would still heat it to get closer to peak performance in the colder weather.

Unfortunately it's now full blown winter here and my 2 wheeled science project is parked for the season.

Just leaving a warm garage will often do the trick, the with enough discharge rate, the battery will make heat. Just depends on how good a heat sink your battery box is. I was having trouble because I built my box for summer, making it a nice aluminum plate heat sink for the lipos. Not so great in winter, but I'd still get in a snow ride of 30 min.

But the in the garage thing, storing my bike in the garage while charging it bit me in the ass real good.

Best approach remains removable battery, in a battery bunker outside, which can be warmed with snake heater. Not working with a bike with built in battery, but you could get small detached shed, insulate it, and heat it.