Why my battery temperature increase faster when I go back to track than first time?

[wzj998]

Hello all, I have purchased and successfully installed the Nür Rear Drive Unit Oil Cooler for my model 3 performance, but the temperature overheat problem still remain.

The 3 pictures attached are the data from three times I entered track in a 2-hour track day event. Before the first time, I used the safety meeting time to charge the battery to 100%. The second and third times, my car returned to the track just after charge finish. Each time it goes on the track, I use 1 cool lap after 1 or 2 fly lap.

Do anyone know why the plateau period when the battery temperature does not rise is the longest on the first time and the shortest on the last time? And what is the next step I need to modify my car for race cool performance? I will be really appreciated for that!

 

[wzj998]

Additional information:
1.These three charts are generated from recorded CSV files using Track Mode, so the battery temperature is a relative value rather than an absolute temperature.
2.The charging station is located near the track entrance.

 

[GtiMart]

You seem to have gone harder on the acceleration on the 2nd and 3rd laps (looking at the output power graphs) which would generate more heat. Are you charging on LEvel2 or on a supercharger? If charging isn't long, maybe your motors stay hot after the first lap so they heat up quicker, dumping more heat into the circuit that's trying to cool the battery?

 

[wzj998]

You seem to have gone harder on the acceleration on the 2nd and 3rd laps (looking at the output power graphs) which would generate more heat. Are you charging on LEvel2 or on a supercharger? If charging isn't long, maybe your motors stay hot after the first lap so they heat up quicker, dumping more heat into the circuit that's trying to cool the battery?

Each charge time is about 20 minutes.

According to the vehicle components' color on center pad, battery and motors seems not hot(green color), so I suspect it's because the coolant is hot when I go back to track.

If my suspicions are true, I'm not sure if it's because 20 minutes isn't enough for the coolant to cool completely, or because charging prevents the coolant from cooling or even heating the coolant.

 

[GtiMart]

20 minutes of what type of power? AC 240V at 20-48Amps or DC 400V at 500+ amps ? Charging heats the battery too, especially high power DC.
EDIT: Since you have proper logging, why don't you look at the initial temperatures for each run? A color on screen isn't precise enough, warm and cold would probably both be green...

 

[wzj998]

20 minutes of what type of power? AC 240V at 20-48Amps or DC 400V at 500+ amps ? Charging heats the battery too, especially high power DC.

about 20+ minutes charge 70% to 90%, and 20- minutes charge 60% to 80%, but when I finish charge the battery color on pad is green, and data in telemetry csv file is 0.666(0.666 is also the smallest battery temp value I have seen in csv).

I wonder how long it takes for people to sit their cars off the track(without charge) before they cool down completely; and if they charge their cars, how long is need to sit cars after charge finish(or maybe do some cool laps just after enter track is more quicker?)

 

[GtiMart]

20% in 20min is DC charging, that must heat the battery too...

 

[wzj998]

Also, Has anyone purchased and installed the cool party controller of Mountain Pass Performance? Will a forced cooldown while charging allow me to have the same experience when I enter the track the second time as I did the first time?
As I always join 1 or 2 hour track event(you can enter or exit track any time during the period). Will the charging time be greatly affected by forced cooling? Will it be better to charge normally first, then find a way to cool down and then enter the track to be more efficient, than use the cool party controller?

 

[wzj998]

Later I installed enhance s3xy button, and know the real battery temp.
I find out that the battery temp in csv file recorded by track mode is not accurate!!!
even the real battery temp is 50C, the value in csv is 0.666 and the color on tesla center pad is green.