Big difference in min/max battery temperatures normal?

[Fastsilver]

Hi everybody,

I have been following this forum for some time now out of interest in Tesla technology and because I was planning to buy one. Since June of this year I own a MYP quicksilver with LG battery pack. Great car overall! So far I did drive a little over 10.000 kilometers and DC charged 40% of the time according to the app. Because I noticed that supercharging isn't that consistent as it was in summer (by consistent I mean that it hit 250kW for a moment) I looked into the service menu for the battery temperature. The attached photo was taken just before plugging into a supercharger. The car did preheat but to my surprise I didn't expect to see such a difference in Min and Max battery Temp. My reference in this case is YouTuber Bjorn Nyland, I very much like to watch his videos and he praises the thermal system in Tesla's due to their small temperature delta in the battery packs.

To get to the point I'm wondering if this is normal and do others notice something similar or might there be something not optimal (like air in the coolant system for instance)?

Thanks in advance for replies!

 

[DownshiftDre]

How long was preconditioning going for before this?

What was ambient temp?

I notice I only get a larger battery temp delta if I dont precondition. For example if I parked at a mall for over an hour and then went straight to supercharger in the same parking lot, there is large delta like this over the duration of the supercharging session.

 

[Fastsilver]

Thanks for your reply! I did start precondition like 25 a 30 minutes before the picture was taken. I can't see the exact ambient temperature but is was close to 13 a 14 degrees celsius.

 

[DownshiftDre]

Were you driving while preconditioning? Typically just driving would put battery at around 30C easy for your ambient temps.

Im going to say your battery temp was low to start with which is also big factor in creating a temperature delta. The way the coolant loop snakes through the battery it takes time to get an even heat.

Another thing to note is this is min and max. Your general average and majority of your battery cells were probably at near the target of 45C.

I think an interesting test would be to see what it looks like when you have a more extended preconditioning while driving. It should be much more equal and distributed. Summer helped as well and now cooler temps makes it more difficult to achieve 100% even distribution.

 

[Fastsilver]

Yes I was driving for one hour before and while preconditioning. I get your point and will certainly watch closer whats going on in the pack (ordered an OBD tool). I was expecting to see a smaller temperature delta, especially with high current charging, for a more evenly cell degradation in the long run.

 

[DownshiftDre]

Yes I was driving for one hour before and while preconditioning. I get your point and will certainly watch closer whats going on in the pack (ordered an OBD tool). I was expecting to see a smaller temperature delta, especially with high current charging, for a more evenly cell degradation in the long run.

Hmm, one hour of driving while preconditioning. You would think it is more even.

I may be doing a trip soon that requires supercharging and will watch. I personally use the coolant loop page. You get to see the battery coolant loop temperature as well.

One thing, just make sure service mode is not disabling heating during supercharging. It is one of the servixe settings and the enable/disable is worded in a confusing manner.