Motor Heat while DC FAST CHARGING

[astegner]

When I fast charge at a public charger my motors start heating up. It is not uncommon for them to reach 298 degrees before cooling. Is this normal? It was in for service and they replaced a fan assembly, but I still see high temps.

Sponsored

 

[dradam]

Seems awfully hot to me. I will be watching the thread to see if there are any good answers. Wish I could help.

 

[astegner]

I was told by Serci e that 300 degrees was still in spec.. I agree.. seems hot.

 

[mikehmb]

If the batteries are too cold, the system will heat them either in preparation for or during a DCFC session.

The 2022-2024 QM vehicles use Bosch motors which are water jacketed. To heat the motors, they run juice through them in a lossy mode to heat them up, then take the waste heat into the pack to warm the cells. Because they are water jacket cooled, the motors have to get very hot to warm the fluid. But it’s still in spec.

If your truck was very cold (and the pack was cold prior to charging) then this is relatively normal behavior.

If your truck pack was already warm, this isn’t normal behavior as far as anyone here as previously reported.

 

[astegner]

Thanks for the info

 

[COdogman]

Unless you’re on fire, you’re good.

 

[CANCERDOC]

It is probably because the coolant loop is shared between the motors and the battery.

 

[HaveBlue]

300 degrees in the battery would be dain bramage.

 

[SPITmadFIRE]

300 degrees in the battery would be dain bramage.

We're very clearly not talking about battery temps here. We're talking about motor temps.

OP this happens when your battery needs to condition for optimal charging speed. Did you notice a slow-ish ramp up to full charging speed during this charge?

 

[astegner]

Correct, motor temps.. Batteries were at about 62 degrees when charging started and it did indeed ramp up the charging rate..

 

[SPITmadFIRE]

Correct, motor temps.. Batteries were at about 62 degrees when charging started and it did indeed ramp up the charging rate..

Yup, then that's normal. 62F is a bit cold for full speed charging. Your vehicle had to warm the battery up to around 80F to get optimal charging speeds, and on the quad motors that means tons of motor heat.

Dual motors are a bit more efficient at generating heat because of the oil bathed Rivian-made motors, so you won't see them heat up as much.

 

[DCFC]

Yup, the system was heating up the motors in order to heat up the battery to enable the battery to accept more power.

Sponsored