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Cooling strategies

Hello, I have three OpenEVSE units in two locations. One unit is set to 16 amps max due to the circuit. The other two are connected to 14-50 outlets and set to 40 amps, and these both experience overheating cutbacks in hot weather. Today is in the mid-to-upper 80's, and the past two weeks were in the 90's (F). Charging my car, max load around 29 amps, these two units will cut back at 65°C. Attached file is a screenshot of the current charging session. The blue line is approaching 7kW, and the red line is just touching 65°C before the cutbacks. I've read the various other threads on ventilation, I'm running the latest firmware on all units. I even added a 1" 12v fan to one unit to stir the air, which helps. But I'd like to reduce the heat buildup itself. Are there mounting options that would help? Spacers for an air gap behind the unit instead of mounting directly to drywall or plywood? A metal backing plate? Should I add solder to the crimp connections to reduce resistance? I've also noticed that the contactor has little sharp turned up corners where the ring terminals meet. These make it hard to get the ring terminals to seat flush. Are there any strategies that help with that? Just looking for some ideas.
1 Comment

The temperature monitoring and throttling feature is very conservative. If you can afford a few extra minutes of charge-time then let the throttling happen as designed otherwise use the menu or WiFi to disable the feature.


The idle temperature will be about 2 - 5C over ambient, there is very little that can be done here as a station is only using about 1.5w with WiFi running.


During a charge session temperature rise is dependent on current. Reducing resistance will reduce heat, the largest factor is the wiring gauge. Thicker wires will reduce resistance/heat. Improving the connections to the relay may help but should not be a factor unless the connection is loose.

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