AlanSubie4Life
Efficiency Obsessed Member
% is completely fine, but does not allow you to directly see capacity loss, if you care about such things (you can still use the energy screen method to see it though, when in % mode).
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2021 model Y scan my Tesla battery size
- Thread starter coconutboy84
- Start date
Contributing a new data point. VIN 207xxx, car picked up 06/09. LR AWD base+red paint, so a 5 seater. 289x109/39.7=79.3.
5/15/30 all yield 79.1~79.3.
I could get as low as 78.8 on a different test.
One thing I’d like to mention is the “since last charge” on the left of the screen. It shows I used 29kwh (or 28.6 if multiplies two other numbers together) today, but my SOC has dropped from 80 to 40. Assuming 79kwh is my 100%, then 79x0.4=31.6. So I lost a whooping 3kw during a few hours of parking. I did notice the SOC dropped 3% in just 2-3 hours today with (non-functional) sentry mode on, only stopped the drain after I turn it off and it went to sleep. These drains are not expected converting from ICE, you are not losing gas parked.
5/15/30 all yield 79.1~79.3.
I could get as low as 78.8 on a different test.
One thing I’d like to mention is the “since last charge” on the left of the screen. It shows I used 29kwh (or 28.6 if multiplies two other numbers together) today, but my SOC has dropped from 80 to 40. Assuming 79kwh is my 100%, then 79x0.4=31.6. So I lost a whooping 3kw during a few hours of parking. I did notice the SOC dropped 3% in just 2-3 hours today with (non-functional) sentry mode on, only stopped the drain after I turn it off and it went to sleep. These drains are not expected converting from ICE, you are not losing gas parked.
AlanSubie4Life
Efficiency Obsessed Member
Thanks for the data. I would guess you would get close to 79.0kWh if you do it at around 80-90% SOC. If there is any weirdness about how Tesla displays the fractional % (slightly off), or you don’t get that digit quite right, that error would be reduced by checking at higher SoC.
But anyway that’s basically what you got…
Your Model Y is so new you should expect that the vehicle is still calibrating the battery pack, battery management system. I suggest you charge the battery to at least 95% to 100% and then drive until the battery SOC is below 30%, even down to 20%. Do this at least twice over as many days as required.
When parked at your home location set Sentry Mode and Summon (if equipped with FSD) to not be active at your home location. These prevent the Tesla vehicle entering sleep mode. Periodically the Tesla vehicle needs to disconnect the high voltage battery pack (as happens in sleep mode) and measure the open cell voltage (OCV) of the cells within the battery pack. Measuring the OCV can take several hours (I recall reading this can take up to 4.5 hours.)
Do you have TeslaFi or Scan My Tesla installed?
Thank you for the suggestions! Yeah, I haven’t charged it over 80% yet. Will do a calibration next. I found several posts reported excess drain while parked so I just assumed it might be bugged or something. But battery calibration should definitely be considered in my case. I don’t have any 3rd party monitoring app installed yet, but may want to install one. Did you imply those could cost extra drain?
If the 3rd party app keeps the Tesla vehicle awake, not enter sleep mode then this would use more power. When the Tesla Model Y is powered on the power drain on the 12V system (ultimately recharged from the main battery pack) is ~220W. When the Tesla Model Y is in sleep mode there are a few components that remain powered on such as the BT receiver and the LTE modem but the power drain is only ~25W.
Just did one on 80% (or 79.5% if we trust the Trip chart) and result comes at 79.24. Looks pretty consistent.
Good point. Interesting all these 3rd party apps claim they don’t have excess drain and pointing fingers to others. Thanks for these numbers, they seems good. I wonder if 220w includes sentry mode on, if so, that’s actually very good.
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I believe the 220W usage is when the Model Y's 12V systems and computer are powered on, at that point I'm not sure if having Sentry Mode actives uses any additional power.
Just did a quick check of this 12v battery, it is about 400wh, it won’t last long before needing recharge from the main pack, and I’d imagine rather frequent replacement for it compare to ICE car.
AlanSubie4Life
Efficiency Obsessed Member
I think the sleep mode power is more like 6-8W, and the battery gets recharged from the HV battery about once every 24 hours (takes about 30 minutes to 1 hour to do that, during that time something like 200W is being used as mentioned above). I thought it was about a 600Wh battery though...
The sleep mode power is a little unclear, but I can say that I routinely observe 18-24 hour recharge intervals on my Model 3. It triggers the recharge when the voltage drops to about 12.7V. And 25W sleep power over 18 hours would be 450Wh of energy use, not even including the idle period. And that's inconsistent with the ~1 rated miles (about 230Wh) of vampire drain I see per day over long periods of inactivity with all feature drain turned off. (Obviously the first day you can see negative drain (add 3 miles overnight, for example) or very high drain due to BMS readjustments - so you ignore that.) So in order to make the sleep current match the observed behavior, it has to come in at around 6-7W (23.5 hours at 6W, 0.5 hours at 150W is ~215Wh).
The battery is not AGM, but it's also I think a somewhat slightly different design than a typical car battery, because cycles are important and "cold cranking amps" are not nearly as important. I don't know all the terminology of 12V batteries, and I don't think it's a huge difference in plate design, but I think there may be SOME changes made to target this use scenario.
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Dumb question. Don’t all these third party apps need your username and password to get the info from your car? NFW I am giving that info to some random app…
but, I appreciate the info shared from people who feel comfortable inputting that info into a 3rd party app.
but, I appreciate the info shared from people who feel comfortable inputting that info into a 3rd party app.
Technically TeslaFi uses an API token you generate by inputting your Tesla credentials (and hopefully your 2FA auth code) and does not store these credentials whatsoever. Technically you could change your password immediately afterward and it would still work since the Token has been generated.
I have a 2021 MYP (04/21 build) with just under 4k miles. Just did the kWh (at 100%) estimate calculation and I'm coming in at 77-78kWh. From what I'm reading on here I should be at 80-81kWh.
Any ideas? Maybe I've suffered some degradation? Or maybe my initial battery capacity started on the low side? I feel somewhat concerned but I don't think there's too much to be done.
FWIW, charge is kept at all times between 20-80% (save for a handful of exceptions). And my lifetime kWh/mi is 302, which again seems on the high side. I might attribute that to mostly freeway driving. Average speeds in my area are regularly above 80-85 mph (plus the omnipresent hot and humid weather).
Any ideas? Maybe I've suffered some degradation? Or maybe my initial battery capacity started on the low side? I feel somewhat concerned but I don't think there's too much to be done.
FWIW, charge is kept at all times between 20-80% (save for a handful of exceptions). And my lifetime kWh/mi is 302, which again seems on the high side. I might attribute that to mostly freeway driving. Average speeds in my area are regularly above 80-85 mph (plus the omnipresent hot and humid weather).
AlanSubie4Life
Efficiency Obsessed Member
I don’t know what the degradation threshold is set to for the Model Y Performance. I think from above for the new AWD with the 82.1kWh battery it is around 79kWh, but we don’t have data from someone below the threshold for the Performance (I think). (That’s the only way I know of to figure out the threshold value without SMT.)
In any case 78kWh is PROBABLY below the threshold (considering the newer vehicles have a 79kWh threshold). The reason it matters is that the method does not show capacity above the threshold. The value is a minimum value (capped by the threshold). Min(threshold, capacity).
What are your rated miles at 100%? That vehicle has rated miles of ~303 rated miles (I think), so if you show lower than that at 100% charge you can be sure your capacity is indeed below the threshold.
Someone here probably knows the actual constant used for Model Y Performance and that would also give you the threshold. I don’t track them for Model Y.
I'll have to charge to 100% and find out. I've never done it before. I think the highest it's been is 90%.
That said, last night I had it at 82% and it was showing 239 miles of range. Extrapolating that out to 100% would suggest that it has 291 miles of range at full charge. Not sure it works exactly like that though. I'm new to this.
AlanSubie4Life
Efficiency Obsessed Member
Yeah it works like that but with the 100% charge you really get the rebalancing etc. and the actual value could be +/-3 miles from that due to rounding error and any rebalancing that takes place.
But just taking your numbers at face value:
77.5kWh for the calculation, with 291 out of the original 303 rated miles, implies 77.5kWh*303/291 = 80.7kWh.
That's the degradation threshold then. We know for Model 3 Performance the threshold is right around 80.6kWh so probably it's the same for the Model Y Performance.
So, you're perhaps 2-3kWh down (maybe less - you really have to charge to 100% to see exactly how much). Totally normal. Just a few % capacity loss in a few months; it happens. Many of the Model 3 Performance are coming in at 79kWh (309 miles out of 315 - would be 297 miles on an MYP; it's the same energy, due to a different constant, 255Wh/mi vs. ~266Wh/mi) in spite of their 82.1kWh battery. So yours is not that different.
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