Regen detail questions

[johnsmj]

I have a couple of questions about how regen works that I have not been able to find answers for:

In dual motor cars do both motors do regen or only one? If one which one is it?

Is the degree of regen limited by the ability of the battery to take energy or limited to achieve a particular degree of braking effect?

 

[GtiMart]

It depends on the situation? I believe both motors can regen (from memory), although I'd have to go drive a bit and look at ScanMyTesla to be 100% sure. Clearly if the wheels slip on ice the regen adjusts itself, I would think it would use the other motor if necessary to try to keep the same braking force if possible. The AWD model 3 is normally rear-biased however, even in acceleration. The front motor is only used on harder accelerations. I *think* that the different motor designs influence this. The rear motor cannot spin freely I think so might as well always use it to power or regen.
The regen is at least limited by the battery temperature as that affects how much power it can safely take without hurting it. So yes, there's a limit in the ability of the battery to take energy. Tire grip is a factor in maximum usable regen as you don't want to lock the wheels. I think there's also an arbitrary limit set so it's not too hard to drive one-pedal. Even if the battery could take 150kW, I don't think we'd like to drive a car that's setup that way... In theory they could augment regen when we press the brake pedal but that's difficult to modulate so the brake feel is consistent. Probably preferable for feeling and security to make the brake pedal only brake using dependable friction.

 

[GtiMart]

Had to go to the grocery store... Once my battery was warm all regen was done from the rear engine, up to 70+kW at highway speed. When the battery was cool I saw around 2kW from the front sometimes. I suspect it was to generate some heat in the front engine so it helps warm up the battery.
This might change when the wheels start slipping. I didn't have an ice rink handy for testing
Also remember that these things can change with software updates.

 

[johnsmj]

Thanks this is helpful. At least you are able to get some hard data that the front motor is contributing. If the regen is not limited by the battery there is lots of room for clever software to help out. For some types of driving more aggressive regen could be fun. The Chevy Bolt has a steering wheel button to turn on regen. Having the ability to temporarily increase the regen could be helpful too.

 

[Candleflame]

Thanks this is helpful. At least you are able to get some hard data that the front motor is contributing. If the regen is not limited by the battery there is lots of room for clever software to help out. For some types of driving more aggressive regen could be fun. The Chevy Bolt has a steering wheel button to turn on regen. Having the ability to temporarily increase the regen could be helpful too.

Teslas already have maximum regen from the get go. No seperate button needed. if you need less regen, press the accelerator pedal slightly.
The chevrolet bolt has the steering wheel button to increase/turn on regen as apparently "the customer preferred to selectively use regen" which is obviously complete BS. If you want to drive a gas car then drive a gas car.
remember the bolt is just a compliance car, not an actual EV.