2016.6 S75 RWD battery range

[cmnaac]

Hi,

I have a 2016.6 facelift S75 RWD. The announced typical range is becoming shorter and the achieved range also. Right now, with around 165k kms @100% SOC the car says 325 Km. As far as the TeslaFI stats shows me, the car is the worst S75 one with more or less the same mileage, ☹.

Additionally, when I stop the can with less than 20%, suddenly the SOC drops some points, 3…4…5 %, ☹.

With all this happening I was wondering if the battery would need some kind of battery balancing, bms calibration, etc. After searching & reading a lot about this, I become curious about the battery modules values, so I’ve bought a diagnostic cable and a OBD Bluetooth dongle to get Scan My Tesla working. Here are the values that more called my attention in different SOCs:

• @SOC 43%: VCell average = 3,764 V, Cell imbalance = 8 mV
• @SOC 12%: VCell average = 3,413 V, Cell imbalance = 29 mV
• @SOC 9%: VCell average = 3,337 V, Cell imbalance = 33 mV
• @SOC 89%: VCell average = 4,105 V, Cell imbalance = 4 mV, during charging
• Nominal Full Pack = 62 Kwh

Apparently, the cells seem reasonably balanced to me, but the bms looks really uncalibrated at low SOCs, do you agree?

For a real SOC of 9% a VCell average should be lower than 3,337 V, or am I thinking wrongly?

This indicates that the battery has more usable energy than the car says and the bms is not allowing me to use because is showing lower SOC % and range values?

What should I do to recover some range availability?

I hope you can help me.

PS: during the week the car is doing around 200 kms per day, more or less half of them in Highway, and using SOC from 90% to more or less 20%.

Best regards

 

[ucmndd]

Right now, with around 165k kms @100% SOC the car says 325 Km.

That’s definitely low, about 202 miles from a rated 249 when the car was new (forgive me for converting your post into stupid American units).

For reference, my late 2016 S75 RWD with 155,000 miles (~250,000 km) charges to about 214 miles (344km) at 100% these days.

Additionally, when I stop the can with less than 20%, suddenly the SOC drops some points, 3…4…5 %, ☹.

This is “normal”, my car does this too with recent firmwares.

Unfortunately I don’t know that there’s a ton for you to do. There isn’t really any sorcery available to regain range. You could ask Tesla to look at it but they’re quite likely to come back and tell you everything’s “normal”.

 

[cmnaac]

That’s definitely low, about 202 miles from a rated 249 when the car was new (forgive me for converting your post into stupid American units).

For reference, my late 2016 S75 RWD with 155,000 miles (~250,000 km) charges to about 214 miles (344km) at 100% these days.


This is “normal”, my car does this too with recent firmwares.

Unfortunately I don’t know that there’s a ton for you to do. There isn’t really any sorcery available to regain range. You could ask Tesla to look at it but they’re quite likely to come back and tell you everything’s “normal”.

Thanks for your feedback.

I don't no if you notie, but @SOC 9% the VCell average is 3,337 V. Does that seem normal for you? I was expecting that for that SOC the cells' voltage should be lower, or on the contrary, for that cells' voltage the SOC should be higher. Do you agree? Does this mean that the BMS is discalibrated?
If you agree, what do you recommend me to do? Some people recommend a BMS callibration, like forcing the cell discharging until some particular voltage? Keep it some time resting and after AC charging it until 100%, and keep it also some time, before start moving with it? Or something else completely different, ?

Thanks again for your help.

Best regards

 

[ucmndd]

I don't no if you notie, but @SOC 9% the VCell average is 3,337 V. Does that seem normal for you? I was expecting that for that SOC the cells' voltage should be lower, or on the contrary, for that cells' voltage the SOC should be higher. Do you agree?

I don’t really know, but this discharge chart seems to suggest that 3.3v at ~10% is not that far off. Also consider that there’s an unusable buffer at the bottom of the battery to protect against complete discharge, so “9%” reported by the car isn’t necessarily 9% at the cell level.

 

[MBluTslita]

After years of being told that my battery readings were normal, I was finally told that there was an imbalance. I just charged to 100%/208 miles on a 237-mile rated late 2016 Model X. Then, I unplugged for about six hours (the tech recommended at least 5-7 hours). Then it was driven this morning and now we have to plug in whenever it’s in our garage with a Level 2 charger. The tech said do this for two weeks and if there is still an imbalance, he would refer it to Service. I’ll update this post in two weeks.