R1T Limited Regen Warning: What's normal?

[jwardell]

Rivian regen is 150kW max. I do not think the battery can not handle that, so it is probably more about overheating the inverters.

But anyway, hope they will tweak it a bit, but full solution will not be possible without new hardware IMHO

150 is plenty! The problem is they won't let you sustain it for much longer than a minute, and it will keep falling and hold to around 30kW. Which is still enough for a gentle slope but not for anyone who lives on a steep hill.

I don't think it's inverter heat at all, but I will specifically look at pack and inverter temps the next time I get the chance. I think it's just Rivian being cautious with pack voltages.

I too have tried to not use the brakes and gone a bit too fast downhill. But keep in mind, tire wear on 21" tires is very expensive! So, I stay in the speed/safe limits and save tire wear, and brake when needed.

Nothing is going to wear tires more than heavy braking!

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[WSea]

150 is plenty! The problem is they won't let you sustain it for much longer than a minute, and it will keep falling and hold to around 30kW. Which is still enough for a gentle slope but not for anyone who lives on a steep hill.

I don't think it's inverter heat at all, but I will specifically look at pack and inverter temps the next time I get the chance. I think it's just Rivian being cautious with pack voltages.




Nothing is going to wear tires more than heavy braking!

Where/How are you getting the regen kw data?

 

[shap]

Where/How are you getting the regen kw data?

I think Rivian removed this information from the service menu, and I just hope that WSea has somehow cracked the Rivian protocol using OBDII. Kyle was talking about some progress on this, but not sure it was materialized at the end.

 

[shap]

BTW, I think we all agree that the problem is really brakes wear in such cases - slowing 7000 lb on regular brakes during going down the hill will have a significant toll on the pads and rotors. If you overheat them you will loose the brakes, they also will deform and you will probably need to replace them.

 

[WSea]

I think Rivian removed this information from the service menu, and I just hope that WSea has somehow cracked the Rivian protocol using OBDII. Kyle was talking about some progress on this, but not sure it was materialized at the end.

I'm afraid that's above my pay grade

 

[usulio]

The inverter as the limiting factor make a lot of sense. The battery can handle 150+ kW sustained when fast charging. Back of the envelope math, we are hitting the regen limiter at much lower recharging power. So the battery is probably not the limiter.

 

[Kärsti]

To get to my house I have a 900 decline over 1.5 miles, I used to get limited regen every time down the hill. The last two updates seem to have made this all but disappear (I am on 2023.22.0).

 

[Greg Chick]

In what mode?

 

[jwardell]

Where/How are you getting the regen kw data?

I can read the data from the motors.

 

[WSea]

I can read the data from the motors.

How?

 

[Greg Chick]

If he can, I will take his techy word for it, the explanation may be even a bigger leap. There are many techy people on this site, I will only add my common sense.

 

[GreenOptimist]

Does anyone know if there is a difference within drive modes? E.g. would driving in conserve extend the time prior to getting limited regen since only 2 motors would be generating power?

 

[Greg Chick]

If he can, I will take his techy word for it, the explanation may be even a bigger leap. There are many techy people on this site, I will only add my common sense.
[/QUOT

Does anyone know if there is a difference within drive modes? E.g. would driving in conserve extend the time prior to getting limited regen since only 2 motors would be generating power?

That is a good question, will the mode use 2 vs 4 motors to Regen? ????

 

[jwardell]

I logged going down my hill yesterday, left a room temp garage at 75%, there's a bit of uphill to the road so it's at 73.6% user SOC at the top and only rises to 74.6% after this ten minute downhill drive.
Have a look at all the data, but to me it's just safe software limiting in the BMS, and hopefully Rivian can improve this in the future.

 

[usulio]

I logged going down my hill yesterday, left a room temp garage at 75%, there's a bit of uphill to the road so it's at 73.6% user SOC at the top and only rises to 74.6% after this ten minute downhill drive.
Have a look at all the data, but to me it's just safe software limiting in the BMS, and hopefully Rivian can improve this in the future.

That was really interesting, thanks! Guess we can't be sure exactly what the software is trying to protect, but we can confirm that the battery is not a limiting factor.

After more experience -- the regen even when limited is still pretty strong. On some solid descents, even with the limiter, I've only barely had to use the friction brakes and I've gotten a good amount of recharge. So the regen limiter might not be as much of a problem as I thought. At least, recharge-wise. It does still make 1-2 pedal driving more finicky.

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