Cold weather battery range loss: Past experiences

[mknox]

That was hinted at (although not stated plainly) in # 9. Higher viscosity lubricant (until warmed up).

I took that to mean "grease" in the wheel bearings and such. I'm talking about a cold car using more battery energy (drive train and cabin heating) until all the systems (cabin, drive unit, battery etc.) in the glycol loops are up to normal running temperature. It seems once you reach this point, there is enough "natural" heating from the motor/inverter and the batteries discharging to keep everything warm without having to use the heating system to do that. Even the cabin materials will become "heat soaked" and it doesn't take much to keep things warm. The longer the trip, the better the overall trip energy use will be because you have more time at "low" energy use to average out the "high" energy use at the beginning of the trip.

 

[jerry33]

I took that to mean "grease" in the wheel bearings and such. I'm talking about a cold car using more battery energy (drive train and cabin heating) until all the systems (cabin, drive unit, battery etc.) in the glycol loops are up to normal running temperature. It seems once you reach this point, there is enough "natural" heating from the motor/inverter and the batteries discharging to keep everything warm without having to use the heating system to do that. Even the cabin materials will become "heat soaked" and it doesn't take much to keep things warm. The longer the trip, the better the overall trip energy use will be because you have more time at "low" energy use to average out the "high" energy use at the beginning of the trip.

The system I was thinking of was the lubricant in the reduction gears. I have an idea that, the friction loss with cold lubricant is substantial. The only measurement I know about is the one the Argonne labs did for the Prius, which came out to about 1/3 of the power used to move the car when cold (as I recall, I couldn't find the actual report--though I know I have it somewhere).

 

[Doug_G]

Lubricant won't matter much. If it is lossy when cold, it will heat up very quickly due to those same losses. There isn't a lot of fluid mass there.

 

[Saghost]

My "most important" factor (not on your list) seems to be "length of trip".

I regularly drive between Toronto and Chicago (just got back after Christmas) and keep detailed logs of my energy use. On those long road trips, even in sub-freezing temperatures, I am seeing only an 8 to 10% increase over "Rated" whereas in the summer I am at, or slightly below "Rated" depending on the particular trip leg.

When I did my 40 mile/ 60 km (one-way) commute, I would see maybe 10 to 15% over Rated in the winter.

On the weekend, when I make frequent, short trips, I will see often more than 100% over Rated in the winter.

It seems the car uses a fairly high amount of energy for the first so many miles, then "settles down" to near Rated numbers after everything is warmed up and the car is moving heat around through the various glycol loops.

Agreed. It seems like the first twenty minutes or so of a cold weather trip are much worse than the rest; my speculation is that this is mostly battery heating but I have no supporting evidence.

My experience so far has been close to yours - a ~10% overall penalty for freezing weather on long trips with heated seats and mid 60s set on HVAC.