How does cold weather effect battery performance and range ?

[David G]

I posted another thread about my first e bike, a trek conduit, having power reduction issues, but i also am having major battery drain issues. I don't know if it's related to the power problems or if it's normal battery issues due to cold weather. ( A the problems started in October when temps were still in the 50s and 60s° F before the weather turned cold, but has gotten significantly worse in cold weather. )
I live in Ohio, USA, and it get into the teens and single digit temperatures from Dec to april...
Can anyone tell me what one can normally expect to have as far as battery life reduction in temps below freezing ?
I went from having a range of 57 miles in eco, 52 in norm, 46 in high, to less than 35 in eco, 23- 26 in normal , and 15-17 in high, and when the temp is below 20 ° F, I'm lucky to get 15 or 17 miles from a full charge, even in eco.
I am having other power reduction problems and am trying to find out if this type of battery life reduction is normal in the cold , or if it's possibly related to whatever is causing the power issues. Shimano sent me a new battery to try to fix the power problems and this one dies much quicker than the original one.
Can anyone tell me what kind of power or range reduction they normally have when it gets cold ? What is to be expected ? And can I do anything to help it ?

 

[David Thomas of Peshtigo]

RE: keeping your battery warmer

My Trek XM700 is equipped with a Bosch ebike system. I purchased a neoprene battery cover that insulates the battery and is said to reduce power loss in cold temps. While I can't quantify its effectiveness, I think this little "jacket" may help on shorter rides in subfreezimg temps. (Actually, I bought it to hide scratches on the battery cover, not for insulation.)

Let's hope that evolving battery technology will reduce cold weather issues. Keep riding!
-- Dave

 

[harryS]

Cold weather, according to the curves I've seen, affects battery capacity by as much as 20% going from 70F to 32F,

If you charged the battery below freezing though, you make it worse. The electrolyte is frozen, and you're forcing it to move ions thru it. Like jamming sticks thru it, I guess, It's destructive. YOu have to warm the battery above 40F before you can charge it. If it's a Shimano battery, it ought to have temperature sensor to prevent that. Cell phones do that.

 

[David G]

RE: keeping your battery warmer

My Trek XM700 is equipped with a Bosch ebike system. I purchased a neoprene battery cover that insulates the battery and is said to reduce power loss in cold temps. While I can't quantify its effectiveness, I think this little "jacket" may help on shorter rides in subfreezimg temps. (Actually, I bought it to hide scratches on the battery cover, not for insulation.)

Let's hope that evolving battery technology will reduce cold weather issues. Keep riding!
-- Dave

I have seen things on insulating the battery, which i will do, but this sort of battery drain seems excessive.. im trying to see whats normal. I will check into neoprene.

 

[David G]

Wow, that's less than i excpeted! I suspect my battery issues are due to whatever is causing the power issues then, because it's easily 75% reduction... or more... just last week I had 80% charge after a 4 mile ride from a full charge, my bike sat outside for 1 hour in 20° F and on the way home it went from 80% to zero in 2 miles... like motor shut off zero... and thats the brand new battery shimano sent me a few weeks ago.

 

[bob armani]

Wow, that's less than i excpeted! I suspect my battery issues are due to whatever is causing the power issues then, because it's easily 75% reduction... or more... just last week I had 80% charge after a 4 mile ride from a full charge, my bike sat outside for 1 hour in 20° F and on the way home it went from 80% to zero in 2 miles... like motor shut off zero... and thats the brand new battery shimano sent me a few weeks ago.

David-I am hoping others with more tech background on this forum can respond to your battery issue. This does not sound like normal functionality in 20 degree temps. I have never had that kind of reduction while riding in those temps on my E-bike. There are a lot of members that ride their fat bikes in very cold winter temps and they get acceptable range that exceeds yours. I could be wrong, however, someone here could possibly clarify. Good Luck.