BMS weirdness

[Zuikkis]

If you park the car below ~10% and let it sit without charging, you’ll “lose” like 5-8% charge as the battery cools. My car does this every time, without exception, as recently as yesterday.

I don’t think it’s actually gone, as in it’s not real vampire drain - just BMS drifting or locking out some capacity as the battery cools.

I suspect the charging complete at 97% is related too. But I also suspect if you run it down again and charge it back up everything will be fine.

I have posted this before in some other thread.. This is temperature vs capacity graph of Panasonic NRC18650PD cell, which is not exactly the cell Tesla uses, but probably is close.

Tesla BMS probably has some absolute lower voltage limit. I don’t know what it is but it is probably in 2.5-3.0V range. You can see that to get the maximum "advertised" capacity the cells need to be at 40C. Any cooler and the capacity starts to drop considerably.

If you could heat the cells you could get the range back, but obviously there's no easy way to do that without external power sources (charging)..

 

[seenhear]

If you could heat the cells you could get the range back, but obviously there's no easy way to do that without external power sources (charging)..

Park it in the sun all day on a hot day?

 

[seenhear]

Vendor - Scan My Tesla, a CANBUS reader for Android

I have a refresh Model S that I would like to use Scan My Tesla on. Exactly what is a "CAN Server"? Is there a cable like there used to be for the older Model S that allows you to plug in the OBDLink? Thanks. CANserver here: CANserver and manual: CANserverManual · joshwardell/CANserver Wiki...

teslamotorsclub.com

No help there either on how to look up or calculate these CAC numbers... they do not show up in the Android app; not that I can find anyway.
Does anyone with Android know how to find these values?

 

[brainhouston]

No help there either on how to look up or calculate these CAC numbers... they do not show up in the Android app; not that I can find anyway.
Does anyone with Android know how to find these values?

Same. Curious why they're not on Android
Only place i see it is in the Diag mode:

 

[seenhear]

Same. Curious why they're not on Android
Only place i see it is in the Diag mode:
View attachment 947626

How do you get to diag mode? Is that within the car, on the tesla app, or part of SMT app?

 

[brainhouston]

How do you get to diag mode? Is that within the car, on the tesla app, or part of SMT app?

Withing a car. I got a code for it after i got mine rooted. Its car specific code.

 

[seenhear]

Withing a car. I got a code for it after i got mine rooted. Its car specific code.

TIL one can get one's Tesla rooted. Interesting. What have you done with root access to your car? I'm not a software guy, so not sure I'd see any benefit. Unless there are some cool apps out there to be had that require root access.

 

[seenhear]

UPDATE:
Well, after weeks of failing to find how to read CAS values, my BMS seems to be acting normally again. Sunday I charged to full for another big driving day. When I came out in the morning, the SOC read 100%, estimated range was 214miles, and BMS reported "charging complete." So maybe it just needed a few days and cycles to reset...

Darn and I was really hoping my battery was about to die. LOL

 

[brainhouston]

TIL one can get one's Tesla rooted. Interesting. What have you done with root access to your car? I'm not a software guy, so not sure I'd see any benefit. Unless there are some cool apps out there to be had that require root access.

Main reason for root is to enable CCS/SC. Diagnostic mode came with it which is really nice for troubleshooting since i don't take my Tesla to Service
Keep in mind this was done before CCS was available as retrofit or even adapter itself.. I had to source parts from Korea n Ukraine..
Neither the Salvage HV inspection was available when i did it, although seems it still unavailable for X...
Additionally with root u can get P2D/glovebox codes.
Unfortunately, no additional apps. Surprising to me as well, i was hoping at least a video player could be added but its nothing like Android root...