Power drop in cold temperatures

[Mteam]

So on another thread the other day I said that I didn't think there was any assistance reduction in cold temperatures, i don't mean battery capacity (as capacity is well known to reduce in cold temps) but I mean the motors ability to pull you up a given hill at a given speed for a given amount of effort.

However today I was out in probably minus one deg celcius, and the assistance from the motor felt significantly lower when the going got really steep, it wasn't too noticeable on more gentle hills, but on proper steep stuff it felt like I was having to work harder than I would normally.

Is this a known thing? That the assistance from the motor decreases in lower temps?

Eco and tour modes felt the same as normal but turbo felt significantly less strong.

If it makes any difference I have a bosch cx gen4 motor.

 

[Zimmerframe]

Could have been the battery ?

Li holds it's charge better in cold temperatures .. BUT - doesn't give out power very well in cold temperatures so often needs warming up first.

If your bike was out all night in the cold for instance, that might explain the power drop ?

Or if you took the battery out as part of your weight loss campaign ? That would result in power loss ....

 

[Mteam]

Could have been the battery ?

Li holds it's charge better in cold temperatures .. BUT - doesn't give out power very well in cold temperatures so often needs warming up first.

If your bike was out all night in the cold for instance, that might explain the power drop ?

Or if you took the battery out as part of your weight loss campaign ? That would result in power loss ....

Battery was definitely installed...

The bikes lives in an unheated but attached to the house garage, it never seems to drop below 8c in there.

I guess im just asking if this is a thing that others have noticed, that motor assistance can reduce in cold temps?

Been doing a bit of go ogling about li ion battery behaviour and it does look like discharge rates reduce with temperature,so that would fit, just wondering....

 

[Zimmerframe]

The motor should perform the same, the batteries - not ! That's why things like Tesla's have battery heaters - even though it uses power to heat the batteries, it's more efficient than not heating them and using them cold.

Maybe it got colder last night ? If it was on a bike rack it would get REALLY COLD ! ...

 

[thewrx]

Yep, thats why i keep my bike indoors before a cold ride (well keep my bikes indoors almost all the time anyway) Once you get juice flowing through the batter from the draw of the motor, it will heat up a bit, but eventually the cold temps will lower the output of the batter no matter what.

I really think heated grips and heated battery pads should be an upgrade option of these bikes. I mean we have the same 217 or 186 cells like a tesla. As there would be no way I would want to ride in 0 C* on my bike without some sort of heated vest and grips like my moto.