So I was going on a 10 degree F 200 mile trip starting at 95%, plugged in and preconditioned. I thought I would be golden, and while I did make it in my '23 MYP, the energy app showed I lost 16% rated range to cold (et als). Being preconditioned, I though the loss would be minimal, then the geek in me came through.
1) Started preconditioned is fine, but on a 3 hour trip, the batteries being exposed to the cold, that preheat is going to need to be supplemented.
2) Internal heating on the battery is likely minimal. Discharge rate is probably something like C/5 on the pack, it's snoozing.
3) Ahhh, the heat pump!
a) Lets say the overall system pack to wheel is 90% efficient. Say you are getting 300W/mile, 60 MPH, 18KWH/hour. Thats 1800W/hour losses.
b) Assume 70% of this can be recovered by the heat pump and it has a COP of 2. That leaves 2*.7*1.8KW= 2.52KW/hour of heat available
c) The cabin at 70F in these conditions, must take at least 1KW, leaving 1.5KW to heat the battery
d) The ability to heat 1200# of battery with 1500Watte is not going to be very good
So at the end of the day, I concluded the heat pump helps, but the car is so efficient, even that can't bail you out of loss of range.
I would love is if someone has some FACTS where my assumptions may be incorrect, please link to source.
1) Started preconditioned is fine, but on a 3 hour trip, the batteries being exposed to the cold, that preheat is going to need to be supplemented.
2) Internal heating on the battery is likely minimal. Discharge rate is probably something like C/5 on the pack, it's snoozing.
3) Ahhh, the heat pump!
a) Lets say the overall system pack to wheel is 90% efficient. Say you are getting 300W/mile, 60 MPH, 18KWH/hour. Thats 1800W/hour losses.
b) Assume 70% of this can be recovered by the heat pump and it has a COP of 2. That leaves 2*.7*1.8KW= 2.52KW/hour of heat available
c) The cabin at 70F in these conditions, must take at least 1KW, leaving 1.5KW to heat the battery
d) The ability to heat 1200# of battery with 1500Watte is not going to be very good
So at the end of the day, I concluded the heat pump helps, but the car is so efficient, even that can't bail you out of loss of range.
I would love is if someone has some FACTS where my assumptions may be incorrect, please link to source.