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I live in florida, you all know the temperature here is closer to hell than any other place. So even in my garage it gets hot especially the Controller, and it is only drawing 13.4 amps per leg on 220 volts.

Is it possible to add a small fan?

and what is the best place to put it and where would it be the air intake?

The only problem it will no longer be water proof.

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Is there any update on this? I have one with the AC contactor. it only does this when its in the sun. It slows way down and displays the temperature. This time it said 55c. What can I do about this? It has worked well for 2 years now as long as i keep it out of the sun. Would putting in the dc contactor help?
Thanks for your readings.
I think I found the suspect.
I have attached the visible photo and the corresponding thermal image from my Flir, of the display chip.
These pictures were taken at the same time as my E8 Flir has both type of cameras on it.
I had auto hotspot turned on as well, and you can see that the display driver chip is 188 deg F!!!!  AND it is HOT to touch (DUH).
I had the unit running for about 15 minutes with my enclosure open, so the driver IC was exposed and not closed up.
The temperature reading according to OpenEVSE was 48 dig C as well, and it was in sleep so not current was flowing.

There IS something VERY wrong with this because when the enclosure is closed up and current is flowing, it will over temp and shut down, unlike your temp graphs.


William, we will replace the display under the 1 year warranty.

OpenEVSE Support

Thank You!  I will perform the same experiment and let you know what I find.


I have had problems with my EVSE overheating also.  Looking back at temp logs it looks like it reaches 65C and then starts to throttle charging, so I don't think it actually shuts down.   But even at idle right now (charging finished about 7 hours ago) temp is at 31C when ambient is only 21C.  This seems high!

Could I have a problem with my display also?  I have seen this overheating problem happen every week or so, and my EVSE is only about 6 months old.

The heat comes from a few places, The power supplies on the controller put off some waste heat (about 1w at max load), the 2 flameproof resistors on the AC_Test lines also radiate a couple watts. The wiring, connectors, fuses, relay coil, relay connectors all put off some heat as well. The higher the current the more heat.

A heatsink inside the enclosure will not do anything, it just moves the hear from 1 place to another. The ambient temperature sensor in built into the display.

The first thing to check is the firmware version. The original firmware 3.7.8 is very conservative, the latest version 3.11.3 is much better. I would also check that the connectors are well crimped and secure, as a high resistance connection can generate a lot of heat when current is high.

What firmware are you running? Versions 3.11.3 and later do not start to throttle until 65C. 

The temperature sensor is on the back of the LCD. If the sun is shining on the LCD it will warm up and provide a higher than normal temperature reading.

The replacement display is on the way. 

Please use caution when installing, we believe this issue is caused by ESD. We had a user who was able to trigger display overheating on demand by walking across his carpet then touching his display. He was using a custom enclosure, we were able to resolve the issue by providing better grounding to the display.

Thank you, Chris. I am familiar with ESD problems, and even with precautions it can still come back to bite you. I will watch my ESD grounding though, and ensure that everything is well grounded, including me! Thanks.
Btw.... even with power applied but not charging, openevse indicates 65C.... and my Flir shows the display driver cooking, so my guess is the temp is real and the chip is running hot... we'll see.

Yes, it is likely the IO expander that controls the display is the issue. The temperature sensor is on the display module as well, it is part of the RTC clock chip. The sensor and IO chip are just a few mm from one another. 

True. My thermal photo shows it being hot,hot,hot!

Adding a fan or cutting holes is not a good idea. Not only does the sealed enclosure keep water out, but it keeps oxygen from getting in if overheating does occur. No oxygen means no fire and a safe shutdown.

What is the maximum temperatur the Open V4 can tolerate? usually mine stay around 32 c (not charging), but some time with a hot day, rise to 65c (charging at 26amp) this is normal?

If it is too hot, they reduce the power itself?

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