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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.

2 people have this problem

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.

In my case the thing that generates the heat is the relay.  If you are experiencing shutdowns due to temperature, you could relocate the relay to another place (if that is what it is).  I see that it is the relay because the temperature goes up when charging and goes down when not.  The only change in the system is the state of the relay.  Obviously there is some heat loss through the wire but that is pretty small.

Thanks for the reply.

No, the relays are not getting hot, the Universal EVSE Controller is the one that gets very hot and the displays flickers a warning ( don't remember what exactly it displayed )  and it stops charging, I was thinking of putting a heat sink on the Universal EVSE Controller but the display won't let me, no room in it.

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.

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?

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.

This is bothersome to me too.
For instance, the outside air temp is 86F, and the internal temp is 64F  withOUT anything running... it is in sleep mode and has been for a couple of days.
If I were to start charging, the temperature would climb to over 70F and shutdown the charge controller due to over temp.
For a test, I opened the enclosure up while charging and the temp dropped closer to 50F, then I used a small table fan and directed the air flow at the controller PCB.  The power supply seems to be the hottest thing, and in my box, it is below the display.
I am going to use my Flir and take some pics of the boards.
I am also thinking of replacing the switcher on the pcb with a couple of external switchers so I can move them around to find a good position.
I might also try moving the controller to another location in my box, to get it away from the LCD/tempsensor, to reduce local heating of the temp sensor.  I can't believe that the power supply is running this hot at idle, no relay pulled, system in sleep mode.


i also should add that my enclosure is a 6x6x6 plastic conduit box made by Cantex.
If it would help, I can post my thermal pictures, or a link to my dropbox acct.


William, Those temperatures are not normal. Something is very wrong if temperatures are 64C. Here is my personal station during the hottest month of summer in the Mojave Desert.


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.


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.
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