Not having regen after the last software update sucks

[Battpower]

Would a change of the threshold of what is considered a "cold battery that needs to be warmed" be consistent to what we are seeing?

Say the old battery temp threshold pre-2019.36 was 55°F and the new threshold is 65°F, therefore the battery would need to be warmed up longer/more before regen is back to normal. I wish the patch notes would mention something like this if it were the case so we would have better expectations of how our cars would perform after an update but maybe its a legal thing so there isn't documentation that they are slowly nerfing our cars in the name of longevity (and potential warranty claims against them).

Sounds quite likely from what I'm reading here.

 

[Max*]

Not long.... To answer your question.....

I was mistaken when I said I've been through 3 winters with my car. This will be my 5th winter.

Any comment I have made about possible 'Energy Saving' is purely comparing energy use to pre-heat vs energy recouped from subsequent regen.

I'm glad we agree that this is speculation. It's possible, sure. But it's speculation until proven otherwise. Whereas the fact that regen was reduced/changed for some people is a fact.

And I also agree, if Tesla just came out and said what they changed, all the speculation and playing devils advocate would go away.

 

[Max*]

Would a change of the threshold of what is considered a "cold battery that needs to be warmed" be consistent to what we are seeing?

Say the old battery temp threshold pre-2019.36 was 55°F and the new threshold is 65°F, therefore the battery would need to be warmed up longer/more before regen is back to normal. I wish the patch notes would mention something like this if it were the case so we would have better expectations of how our cars would perform after an update but maybe its a legal thing so there isn't documentation that they are slowly nerfing our cars in the name of longevity (and potential warranty claims against them).

I think that'd definitely part of it, and it could potentially be all of it.

If the new threshold is 65F, it would also take longer to reach that threshold while driving to work (a few people here commented the regen never comes back during their commute, I'm in the same boat).

 

[aerodyne]

Yeh.

Do any OTA updates require EPA approval?

I do not know, WAG is probably not.

Here in sunny Kalifornia, we have another layer of regulations known as CARB. Say I had found a device for a hybrid electric car that modified the power train computer to give BETTER efficiency. I still could not install it unless it was CARB approved.

if the vehicle was subject to smog inspection, it would fail said inspection.

Of course, many install devices on exempt vehicles for nefarious reasons, and with impunity in the heartland, which is the locus of the coal rolling pickups.

 

[David99]

The battery heater on the Model S is 6kw, so it takes a long time to heat the battery. If you are in a hurry to heat the battery, just do a few full pedal accelerations. A ludicrous launch on a P100D causes a 90 volt drop across the battery at 1850 amp. That's 166kw. Plus you get the additional i squared r losses across the motor and inverter. Even a much more moderate acceleration of a non-performance Model S will have a 60 or 70 kw drop across the battery. As the battery begins to warm, regen will also heat the battery.

This is no more wasteful than heating the battery slowly with the 6kw heater. It's just faster.

Preconditioning might be a better choice, though, except for return trips.

Don't do that. That's literally killing the battery. Drawing full power from a cold battery is a bad idea.

 

[David99]

From data logging over the last years I have learned that the Model S is using the battery heater when the battery is below 26 C /78 F and when plugged in at a supercharger. So in order to get unrestricted charging, the battery temperature has to be that high at least. I have just recently confirmed that again while supercharging.

I have not updated to 2019.40.x yet. I will do some data logging specifically focused on regen and battery temperature and power limits set by the BMS. Then I will do some more after I updated. It should be easy to see if there were changes made.

 

[rsg123]

From data logging over the last years I have learned that the Model S is using the battery heater when the battery is below 26 C /78 F and when plugged in at a supercharger. So in order to get unrestricted charging, the battery temperature has to be that high at least. I have just recently confirmed that again while supercharging.

I have not updated to 2019.40.x yet. I will do some data logging specifically focused on regen and battery temperature and power limits set by the BMS. Then I will do some more after I updated. It should be easy to see if there were changes made.

Has anyone currently logging data verified that the new updates don’t activate the battery heater on cold day trips and instead let the battery warm up on its own? As others have speculated that might be why regen has become so limited. That’s probably great for people jumping right on the highway but not so much for stop and go traffic.

 

[CraDavis]

I had another similar thread going on this recently. Preconditioning seems to no longer include activation of the battery heater. Some have had limited success with scheduled departure but that only works if you're leaving from a place where you're charging.

 

[tomas]

FWIW, I always park in garage heated to 45 Fahrenheit. I usually have regen limited at 30 during winter when I set out. Today I picked up car from annual service. It was out all night in 20 Fahrenheit. Took 4 miles to start any regen, and about 6 to get to 30 limit. Throughout I could hear something loud cranking. I presume battery heater pump.

 

[TIppy]

Don't do that. That's literally killing the battery. Drawing full power from a cold battery is a bad idea.

The won't let you. I just gave those numbers to give an idea of the magnitude of power being generated. You can accelerate at the max allowed by the bms and heat the battery pretty quickly.

 

[SSedan]

I had another similar thread going on this recently. Preconditioning seems to no longer include activation of the battery heater. Some have had limited success with scheduled departure but that only works if you're leaving from a place where you're charging.

That is warming specifically to charge

 

[PhilDavid]

I wish Bjorn could do some tests and let us know what is going on. Is he on this forum?

 

[PhilDavid]

The won't let you. I just gave those numbers to give an idea of the magnitude of power being generated. You can accelerate at the max allowed by the bms and heat the battery pretty quickly.

Have you checked to see how much spirited driving you need to do to get regen back?

It seems the regen change is especially bad for customers who live in cities with lots of stop and grow traffic. Ironically this is when regen is the most useful. After the recent software update, I no longer have usable regen during my commute to work or back home.

 

[TIppy]

Have you checked to see how much spirited driving you need to do to get regen back?

It seems the regen change is especially bad for customers who live in cities with lots of stop and grow traffic. Ironically this is when regen is the most useful. After the recent software update, I no longer have usable regen during my commute to work or back home.

I haven't tried it personally as I live in Florida, but Bjorn had a video where he did some rapid accelerations and regens to get his battery temp up so he could supercharge at a faster rate. I think it was 5 or 10 minutes. He said the time he spent doing this was quickly made up by the faster charge rate he got. Fifteen 0 to 60s should be like 10 minutes of driving for a standard Model S.

 

[PhilDavid]

I haven't tried it personally as I live in Florida, but Bjorn had a video where he did some rapid accelerations and regens to get his battery temp up so he could supercharge at a faster rate. I think it was 5 or 10 minutes. He said the time he spent doing this was quickly made up by the faster charge rate he got. Fifteen 0 to 60s should be like 10 minutes of driving for a standard Model S.

I would love to see Bjorn make a video about this so we know what the exact limits and temperature ranges are.

Do we know if the lack of regen also affects Norwegian customers?

 

[ReddyLeaf]

Same here: I thought I was imagining it at first, and kept trying to figure out what I was doing differently this year to cause it. Glad to see it wasn't just in my head. Hopefully it's a temporary condition, and Tesla will restore our cold weather functionality. (unless there's a really good reason why they did it).......

I just downloaded the software and have yet to drive but... Charging too quickly when cold is the worst possible thing for lithium ion batteries. It causes irreversible Li plating on the electrodes. It’s likely that Tesla is trying to reduce possible damage by reducing regen.. Yes, it’s not fun and I’ll have to change my behavior a bit, but I’d rather have a battery that lasts 20 years. Since all of my in town driving is in a 2011 Leaf with the original battery, I’m well aware of how to deal with zero regen.

 

[SSedan]

I have enjoyed Bjorn's videos but you realize Oslo's weather is ballpark Chicago, definitely cold but there are a few of us in this thread in colder climates.

 

[sd_tom]

a few of us in this thread in colder climates.

and a few of us in much warmer climates.. we shouldn't have to even be in this thread

 

[cucubits]

It’s likely that Tesla is trying to reduce possible damage by reducing regen

Wonder why is it so hard to send out some announcements or tweets or whatever with what they are doing with these updates. Lots of folks wouldn't complain/mind if it's indeed made with the purpose of protecting and/or prolonging battery life.

 

[SSedan]

I just downloaded the software and have yet to drive but... Charging too quickly when cold is the worst possible thing for lithium ion batteries. It causes irreversible Li plating on the electrodes. It’s likely that Tesla is trying to reduce possible damage by reducing regen.. Yes, it’s not fun and I’ll have to change my behavior a bit, but I’d rather have a battery that lasts 20 years. Since all of my in town driving is in a 2011 Leaf with the original battery, I’m well aware of how to deal with zero regen.

But if they let cars have too much regen from 2012 till 2019 and it harmed batteries it is on them to fix, and if they have to manipulate things as a stopgap they need to articulate that. Maybe the "fix" is extending the warranty, but Tesla should be explaining things.