Sub-zero charging rate?

[victor_2019]

What is the normal charging rate on a cold kona?

And by cold I don't mean "UK" cold where it's 7 degrees C, I mean Quebec cold where it's -10 to -20 celsius.

This morning it was about -9 and I preheated my kona for 30 min then drove to work for about 15 min. I plugged in a 50kw charger at work and with 14% battery I was only getting 18kw charge rate.

Does this rate improve after a short time or does it stay this way?

I've been searching on Google for this but the videos I find are from England and what they consider cold is not really the same as what we consider cold. Are there any tests done in Scandinavia or other real cold places you can point to?

 

[apu]

That sounds about right, have a look at Bjorn Nyland's YouTube Kona videos testing in similar cold Norwegian conditions.

 

[KiwiME]

What is the normal charging rate on a cold kona?
And by cold I don't mean "UK" cold where it's 7 degrees C, I mean Quebec cold where it's -10 to -20 celsius.

I plotted the battery heater starting when the battery was under 15°C, which accelerates the time needed before the normal full rate can be achieved. I posted that on a German group and was countered with this graph from lower temps, ones I'll never see here. The rate is dismal at around zero so you can only guess as to what -10 to -20 would be. The spikes on the battery heater temp line are most certainly due to the heater not seeing coolant flow for a moment at starting and stopping conditions.

 

[electriceddy]

I plotted the battery heater starting when the battery was under 15°C, which accelerates the time needed before the normal full rate can be achieved. I posted that on a German group and was countered with this graph from lower temps, ones I'll never see here. The rate is dismal at around zero so you can only guess as to what -10 to -20 would be. The spikes on the battery heater temp line are most certainly due to the heater not seeing coolant flow for a moment at starting and stopping conditions.
View attachment 6728

The pack sure takes a "charging hit" once the cell temp hits 5 C. You would think the BMS would ramp up slower than that
That in rush must stress the cold cells, not good.