Welcome Rad Power Bike owners!

Buying a Rad Power Bike? Support the forum and use my affiliate link:

Be sure to sign up for a free account to see posted images.

Note: To help support to ongoing costs of running
the site we use Amazon affiliate links.

Main Menu

Battery care in Winter

Started by Paco, November 20, 2023, 09:12:43 AM

Previous topic - Next topic Rad E-Bike April 2024 Promotion


hey guys. I have been enjoying my radctity plus since early August-I even did the hack to increase the top speed and I got 37km instead of 32km (I'm in Canada km is all I understand!) and I can feel all pedal assistance levels are stronger...just a bit but enough- of course it drains the battery a little faster but thats ok...and on this topic...I will bike as long as there is no ice on the ground! but in real life tests, what's the coldest this bike can be ridden? will the battery die in minutes in -10C? Will cold weather render the brakes useless? I dunno much about bikes clearly! and finally, for the Winter, I will keep my bike in the garage but will bring the battery inside-I read somewhere that I shouldnt keep the battery fully charged but rather half charged for storage? What's your opinion Radcity riders? Thanks so much


John Rose

Something I caught on one of those many scary youtube videos about lithium batteries bursting into flames was the idea of not trying to charge a really cold battery right after riding around in sub-zero weather. If your garage isn't heated it may be a problem. [edit - Oh, I just noticed that you said you were going to bring the battery inside.]
They said it was best to bring it up to room temperature before putting it on the charger. I forget how cold they meant, and how long to wait.
I wish I could remember which video it was.

About the battery dying in the cold I don't know (yet). I used to live in the Arctic and I recall that at -30oC flashlights with alkaline batteries would die in a few minutes, even if they were turned off; but Ni-Cads were good for almost as long as they would be at room temperature. We didn't have much in the way on lithium batteries back then to compare them to.
RadMini ST 2 / RadExpand 5


John Rose is right. Make sure your battery is up to house temperature before charging it. Also for safety while charging a battery, just make sure you are present, you don't charge it overnight and you use Rad's charger. Rad's batteries are pretty safe as they use quality cells, have a decent Battery Management System (BMS) and they are CE certified (European Union standards). I think they are working on getting CSA and UL listed too.
Your ebike battery will lose capacity in the cold. However, if your rides are relatively short it shouldn't be a problem as most of us ride less than 10 Km when we ride and that's not an issue with an ebike. When you stop somewhere take the battery inside with you so it has a chance to warm up a bit. It's what I do although I don't do it for the sake of the battery. I do it as they are ridiculously easy to steal if left on the bike.

John Rose

FWIW I rode my RadMini ST2 for 11 km today, when it was hovering around 0oC, and when I got back home I still had all 5 bars of battery power left. (Not that 0oC is particularly cold, even by East coast standards.)

I also had the good fortune to have located my snowboard/skating helmet in the bottom of a closet. It has some nice cosy insulation on the inside and over the ears. That worked out very well.
RadMini ST 2 / RadExpand 5

John Rose

Quote from: Paco on November 20, 2023, 09:12:43 AM... I'm in Canada ...
So, are you talking like Vancouver winter, or Tuktoyaktuk winter?

I just found this too:
... and among other things it sez:
QuoteDon't Ride in Sub-Zero Temperatures
Rainy season sometimes means cold weather. Like, really cold weather.
When the temperature drops below zero, it?s a good idea to stay out of saddle. In order to keep your battery operating normally, avoid riding your bike in temperatures lower than -4 ?F /-20 ?C.
Well, that limitation isn't too awful. At -20oC I'd start to be worried about cracking the insulation of flexing cables and maybe even the effect on the rubber of the tires.

They're still not exactly clear if they mean "operating normally" for the duration of the ride, or does it concern permanent degradation.

[What is wrong with how the forum renders a degree symbol? It looks fine in the previews, then turns into a "?" when it's posted. Using ° doesn't work.
Workaround: use a lowercase "o" and apply the "Superscript" style with the "sup" button.]
RadMini ST 2 / RadExpand 5


thanks guys for the messages...I think the coldest I would try is -5 as long as there is no snow on the ground. I'm not a winter warrior! I have a thin head cover that protects my ears and that fits under my  Lumos helmet but it would be nice if there is a helmet that has more insulating material...I'll look online.

About the battery...yep..definitely will take care of it and not charge it while cold! I'm really enjoying this bike-I don't bike more than 14 km a day. It's a bit heavy but that's ok.

safe riding guys


Ever since I took a spill riding on wet leaves. I am now a fair weather rider. I am not taking the bike out until I see asphalt on the road.
I wish I was back in Vancouver. I would like to do the Vancouver Island / Sunshine Coast loop on an e-bike.
So many places in BC that I have taken for granted. Now I missed them all.
Literally is LITERALLY the most annoying word of the decade.