So, it’s well-known that lithium batteries lose capacity when temperatures drop well below freezing. However, since they generate some heat while discharging too, it seems logical that insulating the battery to retain this heat could help extend range in cold weather. My question is whether this makes a noticeable difference in real-world use?
I’ve been browsing eBay, but most covers seem to fall into two categories: uninsulated rain covers for external batteries or neoprene sleeves for built-in ones. My fatbike has an external battery, so I quickly jerryrigged a cover using a 20mm Armaflex sheet I had lying around. While it obviously didn’t hurt, I can’t say I noticed much improvement either.
Does anyone have long-term experience with insulating battery covers? I’d also appreciate recommendations for a good cover for external battery or tips on how to DIY one.
What a thorough reply, thanks a ton for your effort!
I’m continuing my experiments with the armaflex cover that I quickly threw together. I was also thinking of buying a cheap thermometer to monitor the temperature between the battery and the cover. Currently it seems like the most difficult thing with it is to make an airtight seal around the battery so that cold air doesn’t get under the insulation. Also the bottom side of the battery is near impossible to insulate so it pretty much can only be done on the top and sides, though I might have an idea for the bottom side too.
Very nice! Might I suggest a thermocouple rather than a thermometer? A thermocouple would be very compact and for the sort that hooks up to a multimeter, it can be taped into place underneath layers of insulation, so you wouldn’t have to remove or reattach it every time you want to take a measurement between rides.
Can you describe which ebike or what battery pack you’re testing with? I want to get a better idea of what you mean by the top/bottom sides of the pack. A link or photo would be excellent.
I was thinking of using one of those thermometers that have a wired probe for measuring the outside temperature as well. That way I could see side-by-side both outside and inside the case temperature.
My bike is GZR Black RAW. What I mean is that insulating between the battery and the frame is the tricky spot and even if I have the sides and top insulated the bottom side will still remain exposed. Infact, it seems as if the dock to which the battery attaches to also acts as a heatsink of sorts. It’s partly made of aluminium. Here’s a picture of what my bike looks like: