‘18 100D Battery in cold weather problem (Regen related)

[Pwdr Extreme]

A little background:
I previously owned an MX90D which I had for 2 winters in Montana, so I’m no stranger to cold weather and the issues it causes. My MX would sit in a heated garage (45-50F) overnight. When I’d head to work which is 35 miles, mostly interstate, the battery would start out with about half of the regen limited. After about 20 miles, the battery would be warm enough that I wouldn’t have any regen limit. Typical MT winter day is in the teens. After sitting at work for 8 hours in below freezing temps the battery would be limited to about 1/3 regen, it would be fully warmed up with no regen limiting by the time I arrived home. Even in below zero weather, the battey would warm up to the point I would have little if any regen limiting during this trip which I would do pretty much every day.

Now my ‘18 MS100D:
In recent weather with the temps in the 40’s - 50’s, my battery would be about 1/2 limited and stay that way for the entire trip. Consistently. Today, it was in the teens, left my garage about 1/2 limited, drove 15 miles and parked for 7 hours with temps in the low 20’s, and full sunshine. When I got in the car at 3pm the battery was completely regen limited, offering no regen whatsoever. After driving for 20 minutes, I had a sliver of regen available, probably about 1/20th of full regen.

Basically, the only time in the last month or so in MT that I have had full regen was immediately after taking it off of the charger, as I drive the battery will actually cool down and start limiting the regen. During a 150mile trip in the 40’s I went from full regen to 1/2 regen while driving.

Range mode off. Heater in the car seems to work well. Driving typical highway speeds of 75mph mixed with some city. Exact same roads I drove for 2 years in my MX.

During the previous 2 years, I NEVER had my MX fully limit regen, even sitting for a full day in below zero weather. I’m assuming there is something wrong with my battery heater, or else V.9 of the software has drastically changed it’s operation.

Anybody else experience something similar now that the temps are dropping? At this rate I will need new brake pads by spring since I basically have no regen braking whatsoever in winter temps.

 

[TLej]

It seems to me that V9 is doing something different with regards to battery heating and regen. I haven’t seen my regen disappear during driving like you have, but it seems to me the car is heating the battery more aggressively now with corresponding power consumption increase. It also seems like regen is more limited in warmer temps than it used to be. Sitting today at -5C as an example, it was completely regen-limited after sitting at work all day. This only used to happen on much colder days - like -20 days. As well, I have noticed the car is limited in the morning when I leave for work, even though it has been sitting in a garage that stays above freezing overnight.

I will say that due to the aggressive battery heating power draw, I do get at least a little regen fairly quickly, 5 minutes of driving probably, and I usually wind up with about 1/3 regen by the time I finish my 16km commute. So we’re not seeing exactly the same things, but some similarities.

 

[Jan Fiala]

Range mode ON ?

 

[Pwdr Extreme]

Range mode off. It seems like I may have a combination of things based on Tlej’s post. V9 is changing things and perhaps my heater isn’t working correctly. I can’t say that I’ve really seen any excessive power draw. But I just installed snow tires a couple days ago, so now I really can’t make a fair comparison anyway.

 

[hiroshiy]

Range mode off. It seems like I may have a combination of things based on Tlej’s post. V9 is changing things and perhaps my heater isn’t working correctly. I can’t say that I’ve really seen any excessive power draw. But I just installed snow tires a couple days ago, so now I really can’t make a fair comparison anyway.

100's and V9 changed the cold weather behaviors a lot I think. It protects battery more in cold - thus limited regen in not so cold weather. I think we would need to time the charge to finish on departure, and use range mode to keep the battery heat if you would like regen rather than cabin heat.

BTW you can tell if the battery heater is on with your app or TeslaFi.

 

[N..8]

Each cell in the 100 battery is having to do less work then the 90 battery did, so it won't generate as much heat. Just a quick guess, also lots of other things at play like the temps hard to compare different days with out a side by side comparision.

 

[Pwdr Extreme]

Same roads, similar weather with 2 years of history on my MX and I'd say it's a pretty consistent comparison. Yes, the difference is the 100 battery and software V.9. Which is why I'm asking if other 100D owners are seeing the same sort of regen performance, or if there is something wrong with my car since it is so drastically different from my 90D MX.

This morning I left a 50 degree garage after 2 hours of charging at 48amps, regen was limited to 1/2 the entire trip. Outside temp was sun shining and 23 degrees.

 

[Pwdr Extreme]

Just now after charging at my office at 48amps in 28 degree sunshine for 4 hours, the Regen is still limited to about 1/2

 

[N..8]

If you know someone with TM-spy that would be the only real way to see what your battery temps are. I know that for 3 ticks of regen it's about 56 degrees and for them to go all away the battery needs to be at 60 degrees.

 

[MP3Mike]

One contributing factor could be that a S100D is significantly more efficient than an X90D so you will generate less heat organically while driving. (The 100 packs are also more dense and so it takes more energy to heat them up, so they will heat slower.)

That and Tesla is probably fine-tuning their BMS algorithm.

 

[Pwdr Extreme]

Thats a good point regarding the differences between the MX90 and the MS100. If others are experiencing the same things with their MS100D’s, I’ll just assume thats the way it is.

Just really dissapointing to have basically no regenaterive braking at all in the winter.

 

[ReddyLeaf]

Try reducing the state of charge. I know the 90S had some degradation problems and all LiION batteries can suffer from irreversible metal plating when charged too quickly in the cold (hence the reason for reducing Regen). I see more Regen at lower SOC.

 

[FreddyC10]

My S100D stays in my garage also. Garage temps usually around 50 degrees when I leave. I have been preheating the car before going out. It seems I am limited in regen only for the first 5 or 10 minutes. Now the outside temps in NJ have been in the 40s lately so not really a good comparison. It seems weird to me your battery would actually be cooling down while driving and your regen actually getting more limited. I think you should give Tesla a call and have them check things out.

 

[Pwdr Extreme]

Regarding SOC: I have my max charge set to 80%, this issue is happening whether I have 250 or 50 miles of range left, and every where in between.

Driving it like an ICE vehicle sucks! The Regen I’m allowed even on a good day is about equal to the drivetrain drag on a regular car, not quite neutral free wheeling, but certainly requires constant braking in every situation, just like a regular car.

Car was on .42 software, just updated to .46 lastnight. If the Regen issue is still the same today, I’m gonna give Tesla a call.

 

[Jan Fiala]

So you say despite long preheating you get almost zero regen on departure?

That makes no sense, preheating heats the battery to approx 30kW regen, which is sufficient for regular braking.

However doing short trips in cold, many suggest to go with range mode on to prevent the car to heat the battery again and again which leads to very high average consumption.

 

[Pwdr Extreme]

I haven’t preheated the cabin for much longer than 30 minutes while hooked to a charger, on my MX just having the car charge in my garage for a couple of hours is all it would take to have no Regen limiting, on the MS it seems if it’s colder than 50 degrees outside, Regen is going to be limited to some degree. The only time I’ve seen full Regen since the temp dropped below 50 is right after supercharging. Which was slooooow.

 

[hiroshiy]

can you check if the batt heater is on after you leave, via the app?

 

[Pwdr Extreme]

The app shows it is not on.

 

[hiroshiy]

Don't know about your actual battery temp, but if the ambient falls 20F and the battery temp is around 45F, the battery heater should kick in. I sometimes have the battery temp drop to 45F (not in Tokyo) and battery heater turns on.

Not 100% sure it's by design, but maybe you can ask the SC to see if the battery heater is working.

 

[Dan Baldwin]

I was wondering the same thing. The regen behavior of my '18 P100D (Colorado) sounds exactly like what you describe. My garage is in the 50s when outside temps are in the 20s. Last week I left my garage every morning and parked my car outside for 8 hours. Leaving the garage each morning I started with 4 yellow lines of limited regen which stayed for the entire 25 mile journey. Returning (after parked outside in 20F for 8 hours) I had full limited regen (7 yellow lines ?) for the entire trip home..