I disabled the temperature fault checking and the unit works fine now. The temperature is reading 32 0 0 now as I suspect the sun was hitting it. I'll check again after the sun goes down.
I had a similar issue last week with my 50A unit. What unit do you have (50A, 30A deluxe, 30A basic), which board version, and what firmware version are you running?
I believe this is a firmware bug, I am guessing the firmware does not know how to handle the sensor when the values go negative. As a temporary work around while the temperature is very cold, temperature monitoring can be disabled in the button Menu.
I believe I installed v3.10.4 but not sure. I had a brief look around the source to see if I could find the location where the temp is read as I figured it might be related to the neg temperature but couldn't find it. I'll keep looking since you confirmed my suspicions.
Temperature in Winnipeg is a frosty -19C (-2F) and my 50A unit is showing red 'over temp' and my 30A basic unit has a red led, so I think I can confirm we have a firmware bug at low temps. Running firmware V 3.10.4 on 50A, and 3.10.3 on 30A. I've disabled the temp monitoring on the 50A unit with the button / menu, and will have to do the same on the 30A basic unit (without button so a bit more complicated).
Chris, I assume you are looking into a code fix or will have Craig K look into this. Let us know when new firmware version is available and we'll test it out.
Cheers, Jim
3.7.8 does not appear to have this menu. Kind of a problem for those of us with an OpenEVSE that live in cold weather states. This is the time of year that reliable L2 charging is needed the most!
Anyway, I'm in the same situation as Tom. Looking for some guidance. Should I update to 3.9.10 to get the option to disable temp monitoring?
Lincomatic has posted a couple fixes:
The first is is for the sensor in the RGB LCD (included in 50A and 30A deluxe kits). I tested it last night and it works, there was a slight issue with temperature displayed the negative sign was added to both the whole number and decimal (-1.-7)
https://github.com/lincomatic/open_evse/tree/development
Today Lincomatic posted a fix for the display issue and fixed the MCP9808 sensor Color LED (included with recent 30A basic kits), it has not been tested yet.
https://github.com/lincomatic/open_evse/tree/temptest
Those who are setup with the development environment environment are welcome to compile and test. Pre-compiled HEX files will be posted after testing is complete, work around are disable Temperature monitoring in the menu or unplug the LCD/LED if running 3.7.8.
The fix for the negative temperature bug has been fixed and tested.
Here is a pre-compiled HEX with the fix for both sendors the DS3231 and MCP9808.
and a Guide for loading:
Same problem i had when temp drops around -10 /-15 Celcius.
Firmware 3.11.3 fixes the issue.
Andrew Sinclair
My EVSE was working fine until the temperature dipped below -10C. Now it is stuck in an over temperature fault. If I query the evse through rapi the response is 2537 0 0.
253 degrees seems high for the cold day it is today. :)
3 people have this problem