Interesting (to me at least) thermal images of a Leaf Charging

I had my thermal camera out to measure the temperature of some FETs on a project board, and thought for fun I would go see what was up with the Leaf. It was not super hot out today, and it has been charging for 5 hours constantly, L1, at this point.

First image is of the Leaf from a good distance away. The mountains are in the background. The Leaf on the right has the cord going over to the left to the street light and the Nissan provided L1 EVSE is connected to a standard 110VAC GFCI outlet on the street lamp post.

Second photo is of the EVSE itself. The post is made of metal (steel most likely) and the foundation it sits on (the cylindrical pillar) is concrete. It is above ambient, but not bad at all. I expected to see more glowing...

Third photo is a closeup of the outlet. The pin being picked up as the hottest part of the image is acting like a heatsink since I can't see "under" the EVSE plug itself. Reading at just under 31C, not bad.

Fourth photo is a closeup on the Leaf of the charge port area, with the J1772 handle still connected. Not warm at all really.

I found the photos interesting, but nothing new revealed. If anything I was surprised by how little temperature variation there was. I expected to be able to see the cord much better.

I'm surprised that the car's roof isn't hotter.

That is pretty cool, I'm going to see if I can build one and play with it!

DNAinaGoodWay said:

I'm surprised that the car's roof isn't hotter.

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Maybe 8:00 p.m. is late enough in the day that radiant cooling (the effect that causes dew) has already kicked in?

Cheers, Wayne

wwhitney said:

DNAinaGoodWay said:

I'm surprised that the car's roof isn't hotter.

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Maybe 8:00 p.m. is late enough in the day that radiant cooling (the effect that causes dew) has already kicked in?

Cheers, Wayne

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It was actually about 7pm when the images were taken. The Fluke has a clock built in it stamps on the images, but I never update it so it is always wrong lol. Like the blinking "12:00" VCR.

This is also an extremely arid environment. We don't get dew except very early in the mornings. No evening dew like in more humid places I've been.

I almost wonder if there is intentional cooling on the roof to let hot air radiate out. Nissan's "thermal management" of the battery is just not put any insulation on the top of the car lol.

2k1Toaster said:

This is also an extremely arid environment. We don't get dew except very early in the mornings. No evening dew like in more humid places I've been.

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You may not get any dew because your dew point is too low (too little moisture in the air), but it is still the case that when the top of the car is open to the sky, and the sun is not shining down on it, it is being cooled by radiant losses.

Everything is a black body radiator. When you stand in a room and the walls are the same temperature as you, your heat losses due to radiating infrared are matched by the incoming infrared radiation from the walls.

When something outside is exposed to the open night sky, it radiates heat out and there is no matching incoming radiant heat to balance it. This causes it to cool off, which is the effect that causes dew (where there is sufficient humidity in the air).

Cheers, Wayne

That's a great tool. I highly recommend it to anyone building an EVSE or installing an EVSE outlet. Use it to check that things are not getting too hot, in other words, to make sure that the connections are good and components are working correctly. When you're dealing with 240V/24A, the energy is definitely available for a massive fire, and one bad connection or flaky relay could start that fire.

I used a similar camera (Flir) on my EVSE and was fortunate that it showed what was expected - very small temperature rises at the right points. For example, the relay contacts and crimped connections were a few degrees C hotter than the rest of the system.

Bob

Yep, I love these cameras. I use them for looking at circuit boards all the time when there's lots of power flow. They see things humans can't until the magic smoke is let out. And that's the first rule of electrical engineering: The magic smoke once released, can never be put back in your device.