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.
Anything that keeps it from freezing would help, just be careful not to let it overheat too. They also sell battery powered heating vests/blankets that could be repurposed into a makeshift heater. Zippo also sells fuel powered heaters (as well as battery powered hand heaters).
My other comment explores how much insulation might be needed to make a battery pack too warm. And it’s a difficult pickle, since insulating a pack well tends to imply that the insulation won’t be removed later. And yet, the narrow temperature range of li-ion means either the insulation must be shed to keep the pack happy or – bizarrely – some active cooling is needed to keep an insulated pack from getting too warm.
Yeah, adding a heater to that mix further complicates things too. You could rig up some thermistors and a display or buy a smol thermometer to monitor it, but most of the pre-made insulators I’ve seen have velcro strips that allow you to take it off as needed.
Personally, I usually just switched to my regular bicycle so I didn’t have to worry about it but last summer the faulty fender on my ENGWE EP-2 Pro failed and broke my arm so I haven’t been able to ride.
Lesson learned: Don’t cheap out on your ride! Don’t think I’ll ever buy an ENGWE again, they wouldn’t even cover my medical bills.
Wait, the fender failed and that led to a crash? Did I miss a post in this community?
The fender of a few different ENGWEs do not have any sort of emergency release to pop them off in the event of a failure, so when they fail (and they often do, because the old mount they used was garbage too), the whole fender wraps around the front tire and sends the rider into the pavement. Sucks to happen at 12-15 mph, but it’s a lot worse at 20+
They claim to have fixed it on newer models but they never did anything about the old ones and plenty are still out in the market now. If you have one, you can either take the front fender off entirely or replace the bolts with zip ties that will brake when the mount fails instead of yeeting you into concrete. Alternately, you can buy a better, safer fender.
If you want to learn more about the subject in general, Sheldon Brown wrote a pretty good article about it. To be fair, it can happen on any bike without a properly designed fender so keep an eye out if you use them. It’s also a good idea to regularly check over every part of your ride and make sure nothing is loose, damaged, etc. (and always wear a helmet of course).
As it happens, I’ve been meaning to get a front fender, as ebike speeds are sufficient for the front tire to fling water up and directly into my face. I’ve never actually owned a bike with a front fender so this is useful info for me. Thanks!
Oh yeah, keep an eye out for those safety features mentioned in the article when you’re shopping for fenders. I use SKS fenders on my commuter and they’re pretty good quality with multiple safety features. I trust them not to fail, and in the event they do, they are designed to fail gracefully.