I have noticed variable regen as well in cooler temps, most notably after a recent update. It is frustrating with a 1/2 charged battery to not be able to count on having consistent regeneration. Because the cold battery will take a charge via wall charging, I have assumed the decreased regen is a concern of traction/safety. If this is the case, Tesla engineers please give us a driver option to have full regen when the roads are not slick.
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Not enough regen braking
- Thread starter SlimJim
- Start date
So if you have ScanMyTesla, you can get data so you don't have to guess "70%". Its more than 70% by the way.
Daniel in SD
(supervised)
Regen is way more power than wall charging. Max wall charge rate is 12kW and I think max regen is at least 70kW. I've also noticed decreased regen this year (in coastal San Diego!) but I think that they're probably just trying to avoid damaging the battery (dendrites
).Regen is way more power than wall charging. Max wall charge rate is 12kW and I think max regen is at least 70kW. I've also noticed decreased regen this year (in coastal San Diego!) but I think that they're probably just trying to avoid damaging the battery (dendrites
The problem I have with your dendrite comment is that regen will get limited, but if you plug into a supercharger you will immediately get a higher charge rate than what regen has been limited too...in all but extreme cold soaked scenarios.
Daniel in SD
(supervised)
Weird.
Limiting regen due to slippery conditions doesn't really make sense for AWD vehicles like mine since they could just do front regen. Also I'm talking about decreased regen where the overnight low is 50 degrees! Not a lot of ice on the roads around here.
Yeah, so it's an easy proof. If you go to a supercharger with any amount of regen dots and get a supercharger rate over 70-80kW then clearly Tesla deems that charge rate to be ok for the battery.
Using ScanMyTesla, it seems that on an LR RWD car the max regen is actually ~65kW. Pretty easy for me to get more than 65kW out of a supercharger even with significant regen dots.
I've noticed that my Supercharging speed and regen capability follow one another very closely. Even just a few regen dots at the end of the line will limit Supercharging to around 50 kW in my experience.
Daniel in SD
(supervised)
This morning after 9 minutes, 52F, < 80% charge. The struggle is real!
Daniel in SD
(supervised)
I avoid SoCal superchargers like the plague.
The interesting thing is at the top of the hill I only have about a third regen dots but as a I go down the hill I lose almost all regen.
I avoid SoCal superchargers like the plague.
The interesting thing is at the top of the hill I only have about a third regen dots but as a I go down the hill I lose almost all regen.
Yeah, so I have seen that as well. Under power you may have a different amount of regen dots as when you are regenerating. That's why whenever I am looking at anything in relation to regen dots I always look at the regen dots while under regen.
AlanSubie4Life
Efficiency Obsessed Member
It's the cloud of lithium ions wanting to get into that anode, probably. The huddled masses yearning to breath free.
My theory is this has gotten worse over time because they've improved drivetrain efficiency (looks like it is probably a quite substantial reduction in total kW of loss), so now there's not enough waste heat to warm things ups.
Yeah, I'd like to see this shown at some point. My guess is it is well correlated. Unfortunately 150kW Superchargers are unusable in San Diego.
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gavine
Petrol Head turned EV Enthusiast
Or through charging, which is why scheduled-departure helps....the battery will be warm because it was recently charged.
Note: L1 charging does not warm the battery. Only L2 and above do.
I'll see what I can do tomorrow morning if I wake up in time to do a supercharger detour on my way to work.
It's not just being lazy. Driving with different "feels" to the car is dangerous. I have expected my car to slow down with my foot off the gas only to find I have to quickly hit the brake. It's also less efficient with less regen. Today it was around 32°F when I fired up the beast and even after driving a half hour up a steep hill the battery wasn't ready for much regen. Then a few hours later I needed to charge and it wouldn't take more than 60 kW. The charger took a crap and when I was reconnected the other car on the pair got the lion's share and I only go 20 kW!!! I called Tesla to find out what happened but that was a pointless effort. They seem to have very limited ability to look into charging problems.
This is just one of the many, many issues of owning an EV that has made me warn people away from them for a while. I tell them to let the market ripen for three or four years at least.
i'm not sure if you were addressing my post or not. The motor doesn't need to overheat. Dump 50 kW into the motor for 10 seconds. Move 5 kW into the battery for less than 2 minutes. See the difference?
Brakes won't take 15 kW continuously. Try driving DOWN Pike's Peak sometime. They need the same intermittent cycle to use for slowing a car in normal operation the motor and battery can provide.
I had very little regen today. My car got up to 90 coasting down hill on the highway after starting at 65. That's no so good.
AlanSubie4Life
Efficiency Obsessed Member
Unless they install chargers at the top of Pike's Peak, or you stop up there for a long time to enjoy the view while your car battery freezes, I suspect this will not be an issue for EVs.
Yes, it's definitely not good to charge to a high level when the battery is cold, if you are expecting a significant downhill. It is something to be thinking about and I'm not aware of a solution. It's definitely beyond the ability of most people to manage appropriately unless the car automatically prevents it, and requires an override, based on where it thinks you are going.
scubastevo80
Member
I've been looking at canbus data on my AWD model over the last few days. The front motor provides no regen, it's all coming from the rear. My car has never had "full regen" available given I've been driving in sub-40 degree temperatures, but all I've gotten is up to 51kW from the rear motor. The front motor data even shows some very minor usage during heavy regen (about 0.5-2.0kw briefly) - from full lift off of the accelerator at 70mph.
I think some people have said this before but it's purely a matter of battery temperature. The battery in the Model 3 really likes to be warm. ScanMyTesla shows some information that helps understand what's going on. I don't like the behavior difference either, but there's a reason. You can't generate electricity and have nowhere to put it.
Under 3 degrees C, I see the max regen at 0kWh, e.g. there is no regen. It starts around 3 degrees and goes up to 85kWh when the battery's somewhere over 20-25 degrees C on my AWD. Sorry I don't remember the exact temperature.
When I plug the car to charge, either at 6kW or 11kW levels, the car starts by heating the battery up, maybe up to 10 degrees C, and then it charges. Similar reason, the bettery doesn't like being charged when it's cold. This is the type of programming that makes our batteries last for a long time with very minimal degradation compared to some other vehicles.
Preheating the car (inside) also preheats the battery. IF you do that, you will have regen when you drive, which fixes the behavior difference. You will lose some kWh in the battery as heating consumes quite a bit of energy.
scubasteve80, I think I've seen my front engine regen. I have also seen it consume power while the back regens when the battery is cold. Clever trick by Tesla to use the regen to heat up the front engine a bit, thus having heat to put in the battery...
Under 3 degrees C, I see the max regen at 0kWh, e.g. there is no regen. It starts around 3 degrees and goes up to 85kWh when the battery's somewhere over 20-25 degrees C on my AWD. Sorry I don't remember the exact temperature.
When I plug the car to charge, either at 6kW or 11kW levels, the car starts by heating the battery up, maybe up to 10 degrees C, and then it charges. Similar reason, the bettery doesn't like being charged when it's cold. This is the type of programming that makes our batteries last for a long time with very minimal degradation compared to some other vehicles.
Preheating the car (inside) also preheats the battery. IF you do that, you will have regen when you drive, which fixes the behavior difference. You will lose some kWh in the battery as heating consumes quite a bit of energy.
scubasteve80, I think I've seen my front engine regen. I have also seen it consume power while the back regens when the battery is cold. Clever trick by Tesla to use the regen to heat up the front engine a bit, thus having heat to put in the battery...
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