Battery during winter

[Kathy Smith]

I realize this is a bit late to ask, since the winter in the Northeast started a long time ago but I was away and totally forgot about my bike. I stored my bike in a shed which is really cold. Is that bad for the bike battery? Should I remove the battery now and bring it to the house?

 

[Art Deco]

I realize this is a bit late to ask, since the winter in the Northeast started a long time ago but I was away and totally forgot about my bike. I stored my bike in a shed which is really cold. Is that bad for the bike battery? Should I remove the battery now and bring it to the house?

Yes you probably should. Someone will jump in with why, but it's not really a big deal if you don't.

 

[Gionnirocket]

I realize this is a bit late to ask, since the winter in the Northeast started a long time ago but I was away and totally forgot about my bike. I stored my bike in a shed which is really cold. Is that bad for the bike battery? Should I remove the battery now and bring it to the house?

Yes bring it in, let it reach ambient temperature and then charge it to just under its nominal voltage for storage...eg... approx 46.5v for a 48v battery.
Search around on here there are several threads on the subject.

 

[harryS]

Here are the specs for some Panasonic cells that are typically used in portable tools and laptops. The allowed storage and discharge temperatures go down to -4F (-20C), You cannot charge them below freezing.

There is a note about keeping the charge rate under .25C below 10C. If you use your standard ebike charger, you'll be OK, but you can also avoid charging below 50F to be sure.

 

[Gionnirocket]

Though allowable, I wouldn't if you can easily store it at a warmer temperature.
Spec of a Samsung typically found in eBike batteries... note the notes.

 

[Art Deco]

Just to be complete it's state of charge that matters, not raw temperature. And if the battery is in a shed, you will forget to monitor the charge, and keep it above 20 percent or whatever level you need.

 

[ki11a]

Its okay to store batteries in cold temps, just not charge them in those temps. If it wasen't good for batteries to be in the cold, how would any of these ebike companies survive shipping ebikes....shipping only in the summer?

 

[J.R.]

I would move the battery indoors and let it sit at room temperature for 24 to 48 hours before charging. Considering it has been in deep freeze for months, give it time to warm before using or charging. Then charge it to 60% capacity. Keep it between 40 and 60% through winter. A cool, cold room is fine for storage, out of direct sunlight. I don't think it's been damaged.

 

[goldconch]

I'd bring the seat post (and any other battery-powered shed items) inside, the rest can stay put. Laptop battery cells can swell with extreme temperature shifts and humidity changes (from condensation)...think of this as a giant laptop battery. I'd want to slowly warm up to room temp, ideally in very low humidity, and if there's no urgency, stabilize for a couple days before attempting a plug-in for recharge. When you do plug it back in, put it somewhere peripheral where you can monitor it, to make sure it's all good. Luckily, winter air is typically drier, and working cooperatively against swelling. It should be okay.

 

[Kathy Smith]

Thank you everyone. I brought the battery to the house and I'm letting it to warm up over several days. Then I'll partially charge it.