I'm not saying they keep zero but certainly not many given they are in limited supply, so the fact that they may not have them in stock is not surprising. Either way it doesn't take 6 months for them to be shipped from the US.
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MASTER THREAD: 2021 Model 3 - Charge data, battery discussion etc
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I'm not saying they keep zero but certainly not many given they are in limited supply, so the fact that they may not have them in stock is not surprising. Either way it doesn't take 6 months for them to be shipped from the US.
AlanSubie4Life
Efficiency Obsessed Member
Was it left plugged in? Might imply a rebalance occurred. A weak brick (this is totally speculative and may not be your issue) would charge to 100% more rapidly during a charge, and the other bricks would be left incompletely charged (assuming that they were lower than they "should" have been at the start of the charge due to prior rebalancing from those bricks to the weaker brick - without this rebalancing they would get to 100% at the same time as the weak brick, in theory). If left plugged in, it could bleed down the weakest cell, and then charge all bricks again to get the rest of the cells charged to a higher voltage. That implies more energy in the pack because the pack voltage is higher during the discharge (even though the weakest brick would still limit the amp-hours available, and that wouldn't change as a result of this rebalance). (V*I integrated over time is the energy...)
(If this were the case, in SMT, at 100% charge, it would have had a really low voltage, and then overnight the voltage would eventually increase.)
Would have been interesting to know what that 77% was in km, and what it projected to at 100%...
That's a big adjustment - people do see that behavior occasionally (usually just a couple % though). Again, to me this implies some sort of rebalancing. The BMS detected the weak brick was lower voltage than the rest, and redistributed charge to it (I don't actually know whether the BMS has this capability, or whether it only has bleed resistors...I thought it couldn't do this redistribution, but I'm not sure...it seems like a very capable BMS could do it). That would again allow more energy to be drawn from the pack before getting to "zero" on the weak brick - and means more range.
This is all totally speculative and may be completely wrong - while rebalancing at a high level isn't that complicated a topic (you just want to maximize the amount of energy that can be drawn from a set of cells/bricks in series), the details and implementation are tricky. It seems unlikely, too, that your issue is as simple as "just a bad brick." This speculation is more just thinking through how a BMS might adjust for certain pack issues - not what yours is actually doing.
Your pack is one that might actually be interesting to see in SMT, just to see what it says about the balance, voltages, etc.!
It's possible/likely the BMS is just really confused or broken due to some pack issue, and that's why it can't get the SoC right.
Did you ask whether they could run remote diagnostics?
If they do diagnose the pack as bad, see whether you can get information on the technician on what they saw, exactly. You never know, they might tell you. Ask about balance, modules, bricks, etc. Would be nice to correlate a particular symptom with a particular type of failure.
Yes for 1-2 hours after the charge completed.
Actually I quickly estimated these percentages from km. 100% range was 459/460km for both numbers (the 77% was 354km and 83% was 381km). Car was not plugged in when this increase happened.
I talked to two people. The 1st one agreed the range was on the low side and he said he could see in the diagnostics that the car was perhaps consuming a lot of energy while parked and didn't see much out of the ordinary otherwise. I was then forwarded to a service center to ask if they could look do a battery check
at the next appointment that I already had for a paint issue. This guy was saying a lot of stuff that didn't sound very coherent to me. Like the standard range for a LR should be 460km, had I tried to reset the MCU, and he said range changes based on whether you do a lot of short trips or primarily longer trips. Finally he proposed that Tesla does a 'range investigation'; I let them know when I make a long drive (120km) and then they will dig through the logs to see if they can find anything.
I actually already have a ODB2 BT dongle, but am still waiting for the adapter so that I can plug it in. Will try SMT as soon as I get it.
You are assuming they either send one instantly when needed or that they routinely send them to have them in stock. For all I know they could wait 6 months before they even send it out because it would mean more profit for Tesla. So until I can get some sort of time frame from Tesla I will not assume it is on it’s way anytime soon.
I have no problem waiting if they A) are up front about delays and B) at least try to be accommodating and make me a happy customer when something that takes a long time to fix happens to a brand new car.
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Yep, got that at least but it does smell bad inside according to my wife so it’s not really that much fun to use. Had some small trips planned that won’t happen now but that’s life.
Not that I am too concerned yet and obviously still learning the vehicle and behavior. But twice now I have observed this occurring.
So I charge to 80% SoC, drive the car, park it where I leave it for 4 days unplugged with usually 72% SoC come back 4 days later with no checking on the app and it is still at 72% or dropped to 71%. Ok fine to be expected after 4 days. Drive home, park in garage at around 62% SoC, and plug in. Charging is scheduled for later in the night. I happen to check on the app again about 2 hours later, SoC dropped to 60%. Did the same thing tonight and it dropped to 59% SoC from getting parked in the garage and getting plugged in to when I checked it about 1.5 hours later.
Is this just BMS shenanigans? Just odd I can leave the car unplugged and it maintains the SoC I parked it with. But then loses 2-3% 1-2 hours after getting home and plugging in.
So I charge to 80% SoC, drive the car, park it where I leave it for 4 days unplugged with usually 72% SoC come back 4 days later with no checking on the app and it is still at 72% or dropped to 71%. Ok fine to be expected after 4 days. Drive home, park in garage at around 62% SoC, and plug in. Charging is scheduled for later in the night. I happen to check on the app again about 2 hours later, SoC dropped to 60%. Did the same thing tonight and it dropped to 59% SoC from getting parked in the garage and getting plugged in to when I checked it about 1.5 hours later.
Is this just BMS shenanigans? Just odd I can leave the car unplugged and it maintains the SoC I parked it with. But then loses 2-3% 1-2 hours after getting home and plugging in.
I just got my adapter and plugged it in!
Nominal full pack is at 62.8 kWh
Attached are the BMS and battery numbers, let me know if there is something else that could be interesting.Attachments
Got an update from Tesla magically today (after talking to my sales contact yesterday). Apparently when they said “we have no clue when we can have a pack in EU” last week what they wanted to say was that the pack assigned for me will get to EU this week so it was sent before my car broke down to be inventory. I think it was going to be in Tilburg this week and then sent from there. And once the service center has the battery apparently it was 1-2 days of work from what I gathered. So depending on when this week the pack gets to Tilburg it could be less than 2 weeks from now until the car is done.
So all in all (if this actually comes to pass), perfectly nicely handled by Tesla expect for the information bit in the customer service area.
So all in all (if this actually comes to pass), perfectly nicely handled by Tesla expect for the information bit in the customer service area.
My initial guess is that not your battery is bad, but your BMS is "drunk".I just got my adapter and plugged it in!
Nominal full pack is at 62.8 kWh
- SoC, cell voltage, imbalance, block volt reports...that all looks right to me.
- Nominal Full Pack and Usable Remaining doesnt...
- ...resulting in Energy Buffer and Full Rated Range being so low as well.
Surely some frequent users around here will come up with some good ideas very soon.
AlanSubie4Life
Efficiency Obsessed Member
Yes, that aligns with what we said (60kWh) above (after scaling from 437km to 459km, 459km *137Wh/km = 62.9kWh). 23% capacity loss is what the BMS thinks.
I don't see any other major issues with your readings other than the huge loss of capacity that the BMS is predicting. Not that surprising (SMT rarely shows anything interesting!).
It would be interesting to see what happens to balance, etc., as you discharge to 60-70% as you did before, and get full captures both BEFORE and after you see major adjustments to the SoC% (assuming it happens again).
I think in order to see anything interesting you have to capture every point of interest... What we would be looking for is to compare everything that SMT says right after a drive to what it says after the battery/BMS has a chance to readjust.
I think I'd also grab a capture after another 100% charge (really no downside to doing so). And again after it has a chance to sit at 100%.
But in the end it may show nothing of interest.
It's not clear to me what the issue is. What is clear is that your battery (or BMS) is currently a disaster! Maybe they'll be able to reset the BMS and it will figure things out (but I kind of doubt it).
Another thing you can try is to try to drive to close to 5-10% SOC and see whether anything changes (you can do this using the cabin cooling (or heating - you have a heat pump so not sure how much faster that would be) on max with the windows open if you wish though it will probably take a while). It's possible it's just confused (but my guess is that something is broken, whether it be BMS or the cells themselves).
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With 4.11V in the cells you are at, at least, 91% real SOC.I just got my adapter and plugged it in!
Nominal full pack is at 62.8 kWh
It should be very strange if you do not have about the same real capacity as ost other in this case.
I would drive it down to about 3-3.1V/cell ( not during full throttle but in park). After this charge to 100%.
The charged number of kWh should be close to 76-76,5kWh in that case( about 80 -3.6kWh buffer).
This ”test” would show the approximate real capacity and it will also show if the BMS is drunk or if all your cells are bad( not very likely). If the BMS is drunk( I support eivissas theory) this procedure might get the BMS sober.
Thanks for all the suggestions all. I will try to drain the vehicle down to ~3.1V/cell and charge it to full see how much goes in. I'm only using a simple wall plug now though, so no power metering there. Could I trust the car for the charge number? Otherwise I'll find a public charger nearby. Or I could estimate it based on charging time, I suppose at 3kW this should be sufficiently accurate.
I also just did a drive and I again saw a significant increase of the available range and full rated range within ~30 minutes after I parked the car. The nominal full pack capacity now sits at 65.1 kWh with a full rated range of 477km. At least these numbers are moving in the right direction...
Right after I parked my car the SOC was at 49%, below a few snapshots within 30 min after that.
I also just did a drive and I again saw a significant increase of the available range and full rated range within ~30 minutes after I parked the car. The nominal full pack capacity now sits at 65.1 kWh with a full rated range of 477km. At least these numbers are moving in the right direction...
Right after I parked my car the SOC was at 49%, below a few snapshots within 30 min after that.
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AlanSubie4Life
Efficiency Obsessed Member
Min CAC (Calculated Amp-hour Capacity) went up which seems to correlate with the increase in capacity, of course.
Not sure what to make of that though or why it is deciding the minimum CAC is higher. Didn't see any change in imbalance or anything in particular.
Mysterious. At least it is trending the right way. I'm curious to know how long it can keep that up. Seems like a good deep discharge, let it sit and sleep, then recharge a few hours later?
Definitely seems to be one of those rare examples where the BMS is way off - but we'll see how far off it ends up being...
Couldn’t it just be a severe case of a unbalanced battery? Because parking the car for hours at different SoCs are supposed to help the BMS learn at that point. So if you drain it to 40/30/20/10% and let it sit half a day at each maybe it would learn what is correct?
I have been wondering the same since the beginning. But so far Tesla did not mention this as a possibility. Yesterday I have been sending them timestamps and descriptions of the events when the SoC/Full Rated Range changed significantly while in park. Hopefully I hear back soon from their technician.
I will try to let it sit at different SoC's while I discharge it over the next few days.
The BMS have that value, 6mV between highest and lowest cell. Se the pictures.
6mV is good balance.
In practical terms 10mV is a capacity difference of about 0.1% so we are seeing in the ball park of 0.06% difference in charge status/capacity between the lowest and the highest cells. I se mostly 4mV when the car is not running and SOC between 20 and 90%.
AlanSubie4Life
Efficiency Obsessed Member
Setting aside the nonlinearity of the discharge curve, isn’t it more like 1%?
1V = 1000mV (very roughly; it’s actually a bit more) from min to max SOC. So 10mV would be 1%?
Of course due to non-linearity it is more capacity per mV in the middle of the range (lower slope, voltages changes more slowly with discharge). But just roughly…
Not that it matters - as you say the captures show good balance. (Though the CACs are not great…not sure how that compares to others, would have to go back and look for other captures.)
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