Regen limited with triangle on descent....

[sorka]

I have a timeshare in Pinecrest CA. In the last 6 months, I've been getting regen limit starting around 25 into my descent.

This was December 10th. Warm for this time of year but 59F is not too cold or too warm for normal regen.

When I first started out, I got the normal regen limit dashed line but no triangle. Eventually that went away and I got normal regen within about 5 miles of starting out.

Then it switched to regen limit again but this time with a triangle.

Tesla first tried to tell me it was due to the drivetrain being too cold. I had to then remind them that this was not the case starting out and that the normal regen limit had already disappeared after it had warmed up.

They are now changing their answer to it was limited to protect the battery. Yet you can see over 30 miles of mostly decent that I'm just about even with energy in and energy out. The descent is fairly mild. There are no long stretches where where I'm regenning more than 10KW or so. This regen with triangle only happens when I have to to come to a stop for a light or stop sign(roughly a dozen stops through Sonoma on the main highway.

This was never an issue the first two years. I guess it's fair to say I'm not satisfied with their answer. They still have the car as I had a dozen or so concerns they're working on.

Advice for what to do next? I already lived for 6 month with a failing cooling louver causing super charging limiting. This regen thing never happened prior to that failure.

 

[ucmndd]

Interesting that it just started.

For what it's worth, a couple observations:

1) I have a steep descent from my house every morning, about 3 miles of intense regen. Toward the very bottom of that descent, I get the dashed line and triangle - every single time since the car was new. I can set my watch by it - state of charge, temperature, etc. has nothing to do with it. SC told me a year ago it's "normal" on steep descents and regen can be limited like this to protect the battery. Since it happens like clockwork for me and always has, I wrote it off as a reasonable explanation and moved on.

2) I've felt like my car has had significantly less regen across the board recently, for the last couple months. I've been wondering if this is due to the "cold" (I'm in the same neck of the woods as you so certainly not actually cold during this non-winter we've been having), but I'm starting to think it's due to a recent software update or other change in behavior. Seems plausible a recent software update with a more conservative regen profile is behind this change in behavior for you.

 

[Pentium2004]

Just guessing here but it's quite possible it's because of the motors/batteries generating heat from regen and it's just limiting when it hits a certain temperature. Same thing happens on the top side when you are accelerating hard for a long period of time.

 

[sorka]

Just guessing here but it's quite possible it's because of the motors/batteries generating heat from regen and it's just limiting when it hits a certain temperature. Same thing happens on the top side when you are accelerating hard for a long period of time.

I've seen that once when doing 3 or 4 hard high speed accelerations in range mode on a very hot day. I no longer drive in range mode unless it's critical. I really wish Tesla informed customers that range mode can accelerate degradation because the battery management will use less energy to run the AC to cool the batteries down in order to maximize range.

But in this case, it was a cool day and the amount of range was a mere few kWH hours.

My guess is that ucmndd is right and that a software update has limited regen regardless of overall battery health.

 

[AWDtsla]

No hard data to back this up, but I'm usually pretty observant about the behavior of the car. Regen limiting is all around much more aggressive this year. I'm sure the cause is also why supercharging speeds blow. The pack can't take it.

 

[sorka]

My supercharging taper is lower than it used to be usually still starts out at 116KW. It just drops faster after starting and then rides a taper curve that is about 10KW less at the fastest point than when it was new. Charging from 10% to 80% takes about 5 minutes longer than it used it. But I don't have an early 90 pack either.

 

[AWDtsla]

My supercharging taper is lower than it used to be usually still starts out at 116KW. It just drops faster after starting and then rides a taper curve that is about 10KW less at the fastest point than when it was new. Charging from 10% to 80% takes about 5 minutes longer than it used it. But I don't have an early 90 pack either.

I have never seen 116kW, thanks to my superior 84 kWh pack.

 

[SSedan]

Regen can begin to be limited all the way up around 50f I say up around because it has been months since I have seen that temp outdoors.
Is the car exposed to outdoor temps below 50f overnight? 1200lbs pack takes time to come up to temp, just because air is warmer doesn't mean the pack is.

 

[AWDtsla]

Regen can begin to be limited all the way up around 50f I say up around because it has been months since I have seen that temp outdoors.
Is the car exposed to outdoor temps below 50f overnight? 1200lbs pack takes time to come up to temp, just because air is warmer doesn't mean the pack is.

My garage stays at 53F, and I have rarely gotten out of limited regen in more than a month. 25 minutes on the highway at 500Wh/mi, at least. Supposedly the new active heat target is 12C which is 53.6F, which still leaves me with less than 50% regen when "preheated"

I'd guess the new non-limited temp is somewhere past 70F.

 

[SSedan]

Is the slab colder and the battery getting colder than you realize?

 

[AWDtsla]

Is the slab colder and the battery getting colder than you realize?

The slab is keeping the garage warm. Also see the part about preheating.