Regen Issues when Cold

[cccmanhattan]

Recently I've had an issue that when I first start out on cold mornings, the regen doesn't work for the first few minutes. I've read in the comments on other threads that the regen can be limited based on SOC or if the battery is very cold, but It's not an SOC issue since I'm rarely charging above 85% and it happens even if I've just been charging and the battery is warmed up from that.

Anyone else had any issues?

Alsok, just for context, I'm driving a 2021 CT 4S

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[FrozenRobert]

Yes. Same here. I noticed the regen will not operate in lower temps, but don't know exactly why.

I just got back from an errand, driving my 4S and it's 0 deg C (32F) here, and the regen worked 100%. But a few weeks ago, when it was -40 (C of F) the car really didn't like it, and regen disappeared until it warmed up.

Not a technician so I can't offer an explanation. For me it was only a small detail, nothing to get concerned about.

 

[Fish Fingers]

I think regen isn't supposed to work at the start of a journey to allow the friction brakes to work for a while and 'scrub up' first.

 

[Scandinavian]

Yes. Same here. I noticed the regen will not operate in lower temps, but don't know exactly why.

I just got back from an errand, driving my 4S and it's 0 deg C (32F) here, and the regen worked 100%. But a few weeks ago, when it was -40 (C of F) the car really didn't like it, and regen disappeared until it warmed up.

Not a technician so I can't offer an explanation. For me it was only a small detail, nothing to get concerned about.

Regen on all EV’s do not work on cold batteries. You can easily see how much regen a Taycan will do. When it is really cold there is close to nothing.

 

[Tornadosailor]

Independent from outside or battery temperature there is no regen after start a Taycan stopped for 6 hours plus (bad for me - my workday usually is 10 hours or so….i enjoy it usually twice a day)
wheelbrakes are used for some minutes or kilometers, until a certain „brakeforce“ has been applied and regen starts.

 

[Windpower]

This is the same with all EVs: a cold battery shouldn’t be charged at a high rate. When charging any EV, whether by a fast charger, slow charger or regenerative braking, the cars electronic system will limit the power going to the battery until it is warmed up.

On my Tesla, in the morning when it’s cold I get a message “Regenerative braking is limited”. This message goes away after a mile or so of driving. EVs will warm the batteries when you start driving and will gradually allow regen braking. This is analogous to gas cars having to be driven slowly when cold until the oil in the engine warms up. If you drive fast with a cold engine, there’s more wear on the engine. Same thing with batteries in an EV.

If you want to drive straight off when the car is cold, just preheat the car. Then regen braking will work.

Edit: as mentioned by others here, in addition to needing to warm a cold battery before the battery can accept regen/recoup power, the Taycan needs to reset the brakes after 6 hours of non-use and will limit regen/recoup for a short period even if the battery is warmed.

 

[cccmanhattan]

These explanations all make sense, but what's alarming about it is:
a) It's not just reduced, it's literally no regen and purely friction for the first few mins
b) the car doesn't warn you

Obviously the friction brakes are plenty to stop the car and it's fine, but it is a bit alarming when you go to slow down or stop and the car doesn't respond as normal. It also shows how much the car uses regen to slow the car down, it's a dramatic different when it kicks back in.

 

[Pouria]

These explanations all make sense, but what's alarming about it is:
a) It's not just reduced, it's literally no regen and purely friction for the first few mins
b) the car doesn't warn you

Obviously the friction brakes are plenty to stop the car and it's fine, but it is a bit alarming when you go to slow down or stop and the car doesn't respond as normal. It also shows how much the car uses regen to slow the car down, it's a dramatic different when it kicks back in.

Experienced this first hand today driving home in the new CT4S and not remembering that new taycans use the friction brakes exclusively for a couple of hundred miles to bed the brakes. Dramatic difference in stopping power compared to my 20204S.

When both regen and friction is used... Omg this car stops on a dime!

 

[kort]

Recently I've had an issue that when I first start out on cold mornings, the regen doesn't work for the first few minutes. I've read in the comments on other threads that the regen can be limited based on SOC or if the battery is very cold, but It's not an SOC issue since I'm rarely charging above 85% and it happens even if I've just been charging and the battery is warmed up from that.

Anyone else had any issues?

Alsok, just for context, I'm driving a 2021 CT 4S

Just replying based on my cold weather experiences with a tesla, when the batteries are extremely cold they just will not accept any regen until they warm up a bit. in the tesla the car would warn you that there was no regen and then after a few minutes of driving at 50+ MPH the regen would return.
one of the more of the battery tech knowledgeable people could explain why this is.

 

[rs38]

These explanations all make sense, but what's alarming about it is:
a) It's not just reduced, it's literally no regen and purely friction for the first few mins
b) the car doesn't warn you

It's clearly mentioned in the car's manual, have a look!

1. Regen is coming late with a new car and new brake discs waiting for 20MJ of brake energy being used.
2. Regen delays every morning waiting to have ~1MJ of brake energy applied. (usually e few minutes or km)

The car does not warn you as the coasting mode is default and does not behave differently.

 

[cccmanhattan]

Strange. I never noticed it in warm weather

 

[JimBob]

It's clearly mentioned in the car's manual, have a look!

1. Regen is coming late with a new car and new brake discs waiting for 20MJ of brake energy being used.
2. Regen delays every morning waiting to have ~1MJ of brake energy applied. (usually e few minutes or km)

The car does not warn you as the coasting mode is default and does not behave differently.

This is not quite what I have experienced. Because of this thread I did a little test. Taking the car out in the morning, the air temperature was about -10C. Using the center console display, I did a number of stops at various speeds. In every case there was no indication of regen on the display until the speed reached was above about 8 kph. It appeared that it was speed and not time or km driven that determined when regen was available.

 

[cccmanhattan]

This is not quite what I have experienced. Because of this thread I did a little test. Taking the car out in the morning, the air temperature was about -10C. Using the center console display, I did a number of stops at various speeds. In every case there was no indication of regen on the display until the speed reached was above about 8 kph. It appeared that it was speed and not time or km driven that determined when regen was available.

For me, this morning, it was about 3 minutes / 1 mile before the regen started while braking. Up to that point, it was friction only and no green indicator on the gauge.

An interesting aside, it's funny how foreign it sounds to hear the friction brakes after getting used to regen doing most of the job.. In my last EV they'd actually get a bit rusty, which the PSCBs don't do, but you still hear the dragging which sounds strange when you haven't heard it for a bit.

 

[JimBob]

For me, this morning, it was about 3 minutes / 1 mile before the regen started while braking. Up to that point, it was friction only and no green indicator on the gauge.

An interesting aside, it's funny how foreign it sounds to hear the friction brakes after getting used to regen doing most of the job.. In my last EV they'd actually get a bit rusty, which the PSCBs don't do, but you still hear the dragging which sounds strange when you haven't heard it for a bit.

It occurred to me that there are two kinds of regen. There is liftoff regen and braking regen. I was talking about braking regen, and I think you were also. Will need to retest as I don't match your results and also do the liftoff regen next time I go out.

 

[cccmanhattan]

It occurred to me that there are two kinds of regen. There is liftoff regen and braking regen. I was talking about braking regen, and I think you were also. Will need to retest as I don't match your results and also do the liftoff regen next time I go out.

Correct, I'm talking about braking regen

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