Cell brick problem?! Your guess means there's a problem over Tesla diagnostic? You're worrying too much about it. Just follow the manual and plug in whenever you can and charge to 80-90%.
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Suddenly lost 10 miles of range.
- Thread starter XLR82XS
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timk225
Active Member
I saw this in another post here, about balancing the cell bricks to each other. I'll try keeping the car plugged in with a charge limit at 90% for a couple weeks straight and see if that helps.
Copied text:
Incorrect-- brick balancing occurs independent of the car being plugged in. It occurs based on SOC above ~85%. Here's the section from the Model 3 Service Manual with the key sentence in bold:
Brick Balancing
Note that the capacity of a pack is limited by the brick with the lowest capacity. When that brick is charging, it will gain voltage faster than other bricks. The HVBMS will stop charge when any brick reaches its ceiling voltage (~4.2V). If one brick has a significantly lower capacity that others, the pack will be limited by that brick which will get to 4.2V faster than the other ones. We refer to the brick with the lowest capacity as: min CAC. In periscope, its value can be seen by viewing the signal: 'BMS_cacMin'
Another limitation could come from bricks being imbalanced, or some bricks with a voltage higher/lower than others. This would limit ability to charge the pack as the brick with a higher voltage than others would reach the ceiling voltage early. Same idea when discharging, the brick with the lowest voltage would hit the floor voltage early which would cause the HVBMS to open contactors from low power
To mitigate this imbalance, Batman has some bleed resistor that can be placed and removed in parallel of each brick via a FET relay. Batman can put that resistor across the brick with the highest voltage which would slightly discharge that brick and bring it back to the level of the other bricks. Batman closes a FET which puts that resistor across the brick. The HVBMS will order Batman to put that bleed resistor across the brick with the highest voltage when Delta V is > 5mv MinBrickV > 4.0v (~85% SOC) && HVBMS State == STAND BY.
Note that Batman can also do balancing when the HVBMS is asleep.
The best way to balance the Model 3 pack is to set charge limit to 90% or higher and let the vehicle sit idle for hours (plugged in or not). 24 hours of balancing can reduce imbalance by 1mV.
Copied text:
Incorrect-- brick balancing occurs independent of the car being plugged in. It occurs based on SOC above ~85%. Here's the section from the Model 3 Service Manual with the key sentence in bold:
Brick Balancing
Note that the capacity of a pack is limited by the brick with the lowest capacity. When that brick is charging, it will gain voltage faster than other bricks. The HVBMS will stop charge when any brick reaches its ceiling voltage (~4.2V). If one brick has a significantly lower capacity that others, the pack will be limited by that brick which will get to 4.2V faster than the other ones. We refer to the brick with the lowest capacity as: min CAC. In periscope, its value can be seen by viewing the signal: 'BMS_cacMin'
Another limitation could come from bricks being imbalanced, or some bricks with a voltage higher/lower than others. This would limit ability to charge the pack as the brick with a higher voltage than others would reach the ceiling voltage early. Same idea when discharging, the brick with the lowest voltage would hit the floor voltage early which would cause the HVBMS to open contactors from low power
To mitigate this imbalance, Batman has some bleed resistor that can be placed and removed in parallel of each brick via a FET relay. Batman can put that resistor across the brick with the highest voltage which would slightly discharge that brick and bring it back to the level of the other bricks. Batman closes a FET which puts that resistor across the brick. The HVBMS will order Batman to put that bleed resistor across the brick with the highest voltage when Delta V is > 5mv MinBrickV > 4.0v (~85% SOC) && HVBMS State == STAND BY.
Note that Batman can also do balancing when the HVBMS is asleep.
The best way to balance the Model 3 pack is to set charge limit to 90% or higher and let the vehicle sit idle for hours (plugged in or not). 24 hours of balancing can reduce imbalance by 1mV.
Thanks Tim. Very informative. On my previous 3 I was charging regularly to 90%. The day I let my charge go down to 60% and charged back up to 90% I lost 10 miles and never got them back. I don’t have the Teslafi range chart anymore as I picked up my new 3 yesterday. Details in my signature.
Sigh, seems like every generation of owners goes through same cycle:
Everything is great!
Uh oh, I’ve only had the car X months and I’ve lost Y %! If this continues, I’ll hit warranty in no time. Wonder what’s wrong with my battery?
Hey, it’s only an estimate, I can restore some rated range by deep cycling a couple of times. Wow, and yet a bit more by letting it balance.
What was I worrying about? I lost 5% in first year, and nothing since!
* then for a few S owners there had been the concern about software limiting, which is real... but hopefully a chemistry issue Tesla is past.
I guess this is valuable in that it drives each generation of owners to “discover” battery fundamentals and learn about Tesla battery management. But it is hard to watch, because we were seeing same litany in 2013.
Everything is great!
Uh oh, I’ve only had the car X months and I’ve lost Y %! If this continues, I’ll hit warranty in no time. Wonder what’s wrong with my battery?
Hey, it’s only an estimate, I can restore some rated range by deep cycling a couple of times. Wow, and yet a bit more by letting it balance.
What was I worrying about? I lost 5% in first year, and nothing since!
* then for a few S owners there had been the concern about software limiting, which is real... but hopefully a chemistry issue Tesla is past.
I guess this is valuable in that it drives each generation of owners to “discover” battery fundamentals and learn about Tesla battery management. But it is hard to watch, because we were seeing same litany in 2013.
FWIW my LR AWD 9/2018 has been slowly dropping from 90% charging I've been noticing but I don't keep it plugged in. Also have not done a rebalancing. I know to expect a certain amount over the first year or so so haven't given it a lot of thought. It was charged last night to 90% and was at 264 and been hovering around that for a bit now.
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It's a real concern to many of us. I have lost 9% of battery. Measured with an OBD2 cable. Now at 70.5 kWh from 77.8 kWh in 17500kms (less than 11000 miles). I never charge on Super Charger... Service Center will tell me stuff like what you said. Your battery is fine... It's an estimate... Enjoy your car... Everything is gonna be ok. But, every month I loose 0.5%. Like a clock.
Then, if I insist, they will tell me to go through absurd calibration processes and charging routines that don't improve anything. Next thing to try will be to sacrifice a couple of goats on top of the car to calibrate the battery.
Well, NO. It sucks. It's the TESLA BATTERY LOTTERY. Most of you will get normal batteries. Others will get this semi-defective batteries that they won't replace because a battery can loose 93 miles and still be in guarantee. Deal with it.
So yeah, when you buy a Tesla, you basically buy a lottery ticket.
And, of course, don't try to expose on the forums that something of the car sucks because all the fan base will defend the brand and will accuse you of overreacting or something.
But a Model 3 only starts with ~74.5 kWh, not 77.8 kWh... So you are closer to 5% degradation.
It's 77.8 including the buffer. The Full Nominal Pack of new cars are around 77 ~ 79, confirmed at the Service Center. One of the guys checked a new car using his tools and it had 78 kWh.
I've tried all sort of different techniques... It's a "problem" on some batteries. I'm sure Tesla knows what's going on there. It's not up to the user. The user did not do anything wrong. They just had bad luck when purchased the car.
It's the TESLA BATTERY LOTTERY. If you got a decent one you should be happy. Some of us got one of the worse quality batteries but Tesla guarantee is very clear... So we can loose up to 93 miles and still have a battery that is "normal".
I'm not sure about trickle charging doing the trick, but EVERY time I supercharge my stated range goes way down. It takes about a month of L2 charging at home to get it straightened back out. It's very odd to me.
I have the same problem. 7/2018 Model 3 LR RWD 20000 miles. At early 2018, the mileage range was pumped up from 310 to 320 by a software update. Then it started to drop about 0.5-1% every month. Right now it's 288 miles for 100%, or 259 miles for 90%. I have contacted the service several times and each time they said the battery is fine and told me different ways how to bring the range up by charge the battery to 90% everyday for 4 weeks, discharge it to low % then charge it to high %... I followed and nothing change except 0.5-1% drop every month. Today, I requested a real battery diagnosis at a service center, they rejected and said they can't do nothing until my battery degraded more than 30%. It's the TESLA BATTERY LOTTERY! How can we bad luck people do?
Well if it makes you feel any better I've got a Sept 2019 LR AWD with only 4,800 miles. Got 310 when new, went to 304, and now at 290 (261 @ 90%). Only supercharged twice and plugged into a Tesla wall connector at home. Thought miles might come back now that it's summer, but no luck (and cycling the battery doesn't change the estimate much). Yep, battery lottery for sure. Car still drives the same though.
I have the feeling they ****ed up with some batteries. They simply do not meet the Tesla brand super quality standard in terms of batteries. Not super bad either. But definitely not as good as their affiliates have been promoting in blogs and youtube. For some reason they cannot keep the quality production to all their batteries. And at this point they may have too many early degradation batteries to replace them all. We don't know how bad they will get in the future either.
I think they badly need the September Battery Day to sell the world they have new technology before the *sugar* hits the fan and a significant amount of people start realising their M3 batteries are not as good as they thought.
I'd not buy a Tesla until September. They'll probably announce by September that all the cars being sold by then will have a new technology that improves whatever some of our batteries are experiencing.
TESLA BATTERY LOTTERY.
G26okie
2020 P3D-
My 2020 stealth performance is now at 300 miles, down from 304 a few days ago 5700 miles on the car and I baby this battery. It's never been below 20%, never above 95%, never supercharged and is parked in a garage.
Showed 310 new, dropped to 309, then 314 when that new 320+ update hit, then 304 for a while and now 300.
Hoping it isn't real degradation as one of the reasons I felt comfortable buying the car was that the model S/X show very very low degradation numbers after 100k+ miles, infact I remember basically seeing less degradation reported on the model S after 100k+ of constant supercharging than we are seeing on the model 3 with under 10k miles.
Showed 310 new, dropped to 309, then 314 when that new 320+ update hit, then 304 for a while and now 300.
Hoping it isn't real degradation as one of the reasons I felt comfortable buying the car was that the model S/X show very very low degradation numbers after 100k+ miles, infact I remember basically seeing less degradation reported on the model S after 100k+ of constant supercharging than we are seeing on the model 3 with under 10k miles.
omgwtfbyobbq
Active Member
I wish people would research battery statistics before sweating. Most cars lose 5% +/- 2% in year 1 and almost nothing thereafter.
PS, the 310 number on the 3 was BS. The RWD 18 was more, the AWD or P with 19 or 20s less. A recent release factored in wheels. When you figure your losses, do it from the wheel adjusted number.
my 2018 P with 18s is 291 and has been for a year. That’s a loss of ~19 miles or 6%, which is within my expectations.
PS, the 310 number on the 3 was BS. The RWD 18 was more, the AWD or P with 19 or 20s less. A recent release factored in wheels. When you figure your losses, do it from the wheel adjusted number.
my 2018 P with 18s is 291 and has been for a year. That’s a loss of ~19 miles or 6%, which is within my expectations.
insaneoctane
Well-Known Member
Seems to me that even if Tesla service observed a bad module or something small enough to drop mileage by 10-20 miles, since it's not enough of a degradation to trip the warranty coverage, it would be considered "normal". If they told you that they noticed something wrong, did more investigation, and decided it didn't trip the 30% warranty threshold, and they did nothing, you'd probably be angry.... I think"normal" means not a warranty concern at this time....
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