Electric Bikes - Cold Weather effects on Battery Charge

What have you experienced so far with your electric bike or kit, the difference in the length of the battery charge lasting between warm weather (70 degrees and up) vs. cold weather (40 degrees and below). 1/2 less maybe in cold weather?

Hey blippo, while I don't have any exact numbers for you, as its pretty variable and conditional, it depends on the battery chemistry. Lithium has only a tiny loss in the cold, NiMH has a moderate loss, whereas SLA batteries lose a great amount of output: the primary reason people can't start their cars in winter, really.

Its not really a case of the energy being lost, its still there. The thing is, because of the lowered output, you reach your cutoff voltage point much sooner, which is why it feels like the battery goes flat so fast.

Thanks Abneycat. Yea I have the Wilderness kit on one of my bikes. It says they use SLA batteries. The first ride out in 40 degree weather there was a noticeable amount of difference. This is the first year I've had an electric bike I'm learning as I go

It's said that SLA exhibits little charge drop-off from sitting. My experience says otherwise. If I charge my SLA's and leave sit for a few days/weeks, even in mild/warm temps, they lose some spunk. Ideal discharge rate/range seems to be best when freshly charged and frequently used. More so with NiMh/NiCd but somewhat noticeable even with SLA's. Lithium seems to be HOT no matter how many weeks they sit in my applications.

I just wanted to cover this sitting business a little before you 100% decide those 40 degree temps are dropping your battery performance. Yes, if the batteries are sitting outside and get cold, they will lose some capacity. But, once you use them - the internal temperature rises and the effects are less noticeable. You can use this principle to your advantage if you charge/store batteries at room temperature - when placed into service during cold weather, the internal temperature will practically maintain itself and you'll experience little, if any drop in range performance.

Charge/excersize batteries frequently and keep them room temperature until you need them. You should have very little trouble reaching maxium capacity if you follow this practice. Remember too that SLA should be charged, even if only a small amount, immediately after each use. Failure to do so will result in excessive plate sulfation and reduce battery life regardless of operating temperatures.

Welcome to the world of eBikes! It get's in your blood...

Yeah I ran SLA's last winter. The drainbrain didn't really show much loss of total capacity when they were left out for a long time around freezing to -10, but they did have less grunt where it mattered (uphill), but I found that leaving the charger plugged in did the job keeping them reasonably happy. Also any colder and to bring them indoors was the trick. They're massive, and even with just a sheet of cardboard around them as insulation they'd keep their heat for several hours. No beef.

My laptop with lithium batteries really isn't happy with cold, after an hour or so in my backpack at -20 the batteries can barely power up the thing before crapping out, by opposition to lasting about two hours at room temp.

Right now I am charging them in my garage which is somewhat warmer than the outside. I'll try keeping them and charging them inside the house. I have alot to learn about batteries

Blippo, you're using a bike with an integrated removable battery case right? Maybe you could insulate the case during the winter to help keep the batteries warmer.

Yes, I could try to insulate it.

I have the PL 350 on one of my bikes. I've had it for around 3 months. It is terrific.