DC fast charging pumps a lot of electrons into an EV, very quickly. We thought it would be fascinating to bring a thermal camera to a Supercharging session to uncover this invisible thermal activity before our very eyes.
It was a cold December day with an ambient temperature of 46°F (8°C), and we arrived at a V3 (250 kW) Supercharger with a preconditioned Model Y battery at 3% SoC. (Go deep or go home, I say)
As we had just exited the highway, the tires were predictably the hottest part of the image on arrival at 65°F. (18°C) But notice how the wheel center caps are made of plastic, and are not conducting heat from the alloy rims.
The front of the car is barely above ambient temperature because we’re not burning dinosaur juice here. The car next to us was charging for a while and built up heat in the fender area, and we’ll see that below too.
Worth pointing out that the Autopilot camera module is heated on Tesla to prevent fogging and icing.
Hot wheels. Cold brakes. Thanks regen!
We drove for two hours on the highway during the winter, before charging I thought I’d measure the frunk temperature where I was cooling some beverages. Turns out the drinks were kept just 10 degrees warmer than outside and good enough to consume.
Now we’re cooking! Because we started at barely 3% state of charge, the Model Y LR was able to pull near 250 kW for a little while. The measurement above was as hottest reading on the cable we observed in the mid-90s. At the end of the charging session (95%), the cable was barely above 70°F. It would be interesting to repeat this experiment in the blazing summer sun.
Just as we saw with the neighboring car earlier, our Model Y built up heat in the fender area after DC charging for a few minutes. Notice that the car is also now cooling the battery and dumping heat from the air vent under the bumper.
The air vent is open and exhausting drivetrain heat into the environment.
At the end of our charging session, the undercarriage of the car had a surface temperature in the 80s, while our OBD2 scanner showed an internal battery temperature above 125°F. (51°C)
Related: How to see battery temperature.
Finally and most importantly, we measured the frunk temperature after the full Supercharging session. It rose by a solid 26 degrees to 76°F. Not exactly ideal for our road trip drinks. 👎