Understanding 85kWh battery limits

[kirkusss]

As I am experiencing some weird behaviors lately, have started looking into what can cause them and what should be the expected performance from such pack.
At this point naming it 85kWh is anecdotal, but I’ll stick to the label.
Early cars are prone of failure due to water infiltration, very helpful thread started by @wk057
That should cover up to the introduction of 85D that seem to have the drain relocated.
The generic BMS errors are a clear indication of most failures, but what can we look after and detect before?
On my car (85D, 105k miles, 698xx VIN) I can see the following:
Power limits on hard acceleration present from 60% SOC (visible after few seconds of WOT)
This seems to be correlated with pack voltage dropping and amperage not keeping up. Probably the Performance packs can keep higher amperage and hide the issue better. Amperage drop with SOC is normal, but what should be the normal voltage sag on these packs?
My voltage sag is between 100 to 120V, minimum that I’ve seen is taking the pack to 249V at 40%. That is under load with cell voltage as low as 2.56V.

Can the high sag and voltage drop on cells be considered as valid metrics for the pack health seen that the BMS will shut down the car at 2.5V?

 

[kirkusss]

Opened a service request with my local SC. They pulled the logs and no surprise, everything is ok on their side on the battery. It seems anything before a failure is ok
Will ask them how come the DI w166 _hvilOutOfBounds did not popped-up in their assessment (still active in service menu)

 

[blodg1]

Opened a service request with my local SC. They pulled the logs and no surprise, everything is ok on their side on the battery. It seems anything before a failure is ok
Will ask them how come the DI w166 _hvilOutOfBounds did not popped-up in their assessment (still active in service menu)

Internal documents show this for DI_w166_hvilOutOfBounds:
"The drive inverter (DI) has detected that the high voltage interlock loop (HVIL) voltage is outside of the specified range. This alert only applies to small drive units.
This alert is set if HVIL voltage is +/-0.3 volts or +/- 1.5ma the nominal value. This alert can be falsely triggered when the DI is outputting higher torque. This alert alone is not enough to identify an HVIL issue."

You can safely ignore it.

 

[kirkusss]

Thank you for that insight.
Unfortunately the power limits are still present and now there is a permanent one below 20% (battery is hot enough to not have power/regen limits).
On top of this, I am not able to use more than 61 kWh on a full charge. Based on scan my tesla numbers I should have 73.2 kWh - the 4kWh buffer.
No idea how to make Tesla look into it without any triggered errors.

 

[kirkusss]

My issue continue, same power limits at wot on highway, but no BMS errors. Other than that I can not use the entire battery capacity that Input in.
Yesterday arrived home with 19% at home, 2h later went to plug in, the car was reporting 15%. That was down from 90% the day before, for a total of 42.2kWh used by driving.
Charged overnight back to 90%, for a total of 55kWh
That’s a big difference, especially the temperature was mild lately and the car is in a heated garage when not driving…
Of course, have no case for Tesla without a triggered error…

 

[Videomatic3]

My old 85d battery pack would run the battery coolant pump needlessly for hours upon hours draining the battery up to 9% per day.
Of course tesla says it's normal, however my new pack doesn't do the same thing. I bought the 1014116-00-c

 

[kirkusss]

Between 2 charges (2 days) I see up to 15kWh missing between the amount charged and used....
And tesla is not helping with anything as you are saying...if there is no error triggered they don't care or have the expertise to properly check the logs.

 

[Lasttoy]

Tesla doesn't care about antique 85s, out of warranty. Their solution is buy a RE manufactured pack for 12k. I'm working with 057 to determine the condition of my pack. Advice. Don't run it below 20% or over 80%. Too much strain on old pack. Set charge to slow at night. Oh. I never get super rate of 70kw .

 

[kirkusss]

Have also sent a message to @wk057 to see if there is a way to check battery health, but I know they are pretty busy. My warranty will run in March, would try to put as much strain on it if we determine that the pack is actually having issues.
From what I can tell the software is trying as much as possible to keep the pack safe, but it cannot hide when power limit conditions are triggered. Don’t know if it makes a difference, I am on MCU2

 

[Lasttoy]

What is a ""power limit condition ". I'm not seen that term?

 

[kirkusss]

Battery too cold, SOC too low, voltage too low, all these can limit power. It all depends if it’s consistent or not. For me it’s all over the place since almost 2 months ago.
Two days ago the 150kW limit came on 29% and stayed until charging at 5%. And yes, battery was above 20 degrees celsius all time.

 

[kirkusss]

Adding the visuals from the case above.
Starting from the heated garage:

After 20km of driving:

After 4h outside:

Back home after another 20km

 

[Lasttoy]

What year was your car made? I don't have anything that looks like that in my antique. I got Infotainment upgrade. I can't find any screens like yours???
My car was made in late 2012, titled 6 jan 2013, so it has all old hardware except for new MCU and screens.

 

[kirkusss]

It’s a 2015 85D. The car was rooted on MCU1 and after upgrade to MCU2 the debug profile carried over
After the Holiday update I did Yesterday, the car is slower and power limit comes on later due to the lower power demand. So pissed I hit that update icon…

 

[aerodyne]

My old 85d battery pack would run the battery coolant pump needlessly for hours upon hours draining the battery up to 9% per day.
Of course tesla says it's normal, however my new pack doesn't do the same thing. I bought the 1014116-00-c

They all do that if you charge over 77%

 

[aerodyne]

It’s a 2015 85D. The car was rooted on MCU1 and after upgrade to MCU2 the debug profile carried over
After the Holiday update I did Yesterday, the car is slower and power limit comes on later due to the lower power demand. So pissed I hit that update icon…

I think it is likely your pack will fail soon, hopefully under warranty. Do all you can to get Tesla to address the issues.

 

[Videomatic3]

They all do that if you charge over 77%

youre just talking about the old 85kw packs right? my new one doesnt.

 

[aerodyne]

youre just talking about the old 85kw packs right? my new one doesnt.

Correct, old 85packs...

 

[EastCoast85D]

Definitely something janky going on with your battery. My 85D has 102k miles and none of those issues. Battery drain on 30 degree days is only like 4-5% over 12hrs to keep the battery warmish. My car is a little newer, my warranty runs out in April. I am also on MCU2.

I am seeing a little less power going off of the Energy gauge but it's been cold here and I seem to get full power around 60-70 degree days. None of the power limiting yellow dashes though and still over 300kw (appears around 320ish from the eyeball).

I also get over 100kw if I supercharge below 20%.

 

[kirkusss]

Have put my theory to the test yesterday. Went for a short drive to do some pulls on the highway (nothing crazy, but power limit activated every time). Arrived home with 25%, battery at 25 degrees Celsius, no power limit present. Left it for few hours and surprise, lost 4% and power limit constant on (around 200kW).
Left it until this morning when I noticed another 5% lost, power limit at ~170kW and regen limits on.
Went for a 5 minutes drive, regen limit went away and power limit stayed on at 170.
Will try replicate the same and go to another local SC.
Unfortunately, the word in town is that SCs are not requesting expensive warranty replacements in this period unless it’s something obvious….