Preconditioning - Paying Twice?

[dleepnw]

the more important benefit of preconditioning is to preserve the life of the battery. i think saving time charging is also nice, especially when you have to take long road trips, it'll add up.

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[JohnB R1T]

When cold, the preconditioning heats the two motors which in turn heats the battery up. This only happened in the AM and not every time. Once it’s warm, the battery never cools down so this warming is a rare, a once per day thing, if that.

Is it actually "heating" the two motors or is it simply not cooling the two motors to allow the heat to build up so that it can be dumped into the battery?

Motors generate heat when running. That's a given. What happens to that heat is a different story.

 

[KeithPleas]

...and it probably would have taken us directly home (where it still doesn't realize we have a charger)

This has been my observation as well. I take quite a few day trips over the mountains to Cle Elum / Ellensburg / Yakima / Leavenworth (we have some properties out that way) and when I selecte "Home" it always directs me to a charging stop. The latest update allowed me to delete that stop, but I think a lot of these whacky home routings suffer because the system doesn't know you have a 100% available charger at home.

 

[R.I.P.]

Is it actually "heating" the two motors or is it simply not cooling the two motors to allow the heat to build up so that it can be dumped into the battery?

Motors generate heat when running. That's a given. What happens to that heat is a different story.

The vehicle runs the motors in a lossy mode to create more heat than they normally would. Essentially, turning the windings into heating elements.

 

[mtberman]

The vehicle runs the motors in a lossy mode to create more heat than they normally would. Essentially, turning the windings into heating elements.

Yep, both the front and rear motors in my DM will heat up to about 135 deg F. This heats the coolant oil, which is then used to heat the battery.

The motors do not have to be spinning for this to happen. The windings are in an oil bath, which runs even at a standstill. The motors heat up and the coolant heats up, which is then used to heat the battery.

 

[Tony R1S]

Yep, both the front and rear motors in my DM will heat up to about 135 deg F. This heats the coolant oil, which is then used to heat the battery.

The motors do not have to be spinning for this to happen. The windings are in an oil bath, which runs even at a standstill. The motors heat up and the coolant heats up, which is then used to heat the battery.

On QM motor heats up a lot higher to around 270F. Outside temp was around 20F.

 

[R.I.P.]

On QM motor heats up a lot higher to around 270F. Outside temp was around 20F.

Correct. The qm has a very inefficient cooling system, which makes it an equally inefficient heater.

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