Hi,
my openEVSE wallbox worked fine for over 2 years, but suddenly stopped charging. My Renault Zoé says “check wall box” endlessly. When connecting, I hear the relay go on and after 4 s off again, no electricity delivered at all.
no errors shown (ground failure etc)
nothing in the logs, nor in debug console, just “charging” and 4 s later “connected”
available power is received correctly via MQTT and MQTT communication works flawlessly in both directions.
another EV on my box produced the same negative results
my EV charges correctly on public charging station, with the same cable I use with my box
contacts on the plug and the cable look clean and shiny, cleaning with electronic contact spray didn’t change anything
Is my relay dead? Any other ideas, or how to investigate?
If the status is showing as ‘Connected’ this mean the pilot signal is telling the EVSE to stop charging and open the contactor. Therefore, I reckon the contactor is probably fine, I would check the pilot wire connections. Assuming the connections are fine, and the cable is good, I would suspect it’s the EV stopping the charge.
Zoe’s have quite a complicated charging system and are sensitive to high earth loop impedance. From memory, I think a Zeo requires less than 150 ohm. How is your EVSE earthed? If it’s from an earth rod it’s possible the earth loop impedance has increased. CanZE Android app with a BT ODB2 dongle can give you info on the earth loop impedance (Ze) value.
Can you test the EVSE using another EV? Other EVs are less sensitive to earthing issues.
Thanks for your feedback. I tried to water the earth rod (the EVSE id on the houses earth rod, in Franc it is illegal to mix installations with different earth rods). I am only guessing where it actually is, I tried right next to the junction board. So far it didn’t change anything, I continue trying.
Is the Zoé more sensitive than the earth check of the EVSE ? I didn’t get any alerts concerning earth resistance. I have tried to measure between PP and the central earth pin in the type 2 plug, but I didn’t measure any resistance (but I am not sure if I use the meter correctly).
How can I measure the resistance of the earth rod? I don’t have an ODB2 dongle.
I only see Zoés around me, no other EV types.
You mean a earth loop impedance meter, this function is built into MFTs (multi function testers) that electricians use. These meters are exolpensive, your best bet would be to ask an electrician.
An alternative is to get a Bluetooth odb2 dongle and use CAN Ze app. I’m not too familer with CAN Ze, but I think it will let you read the Zoé’s onboard earth loop reading.
As far as I know, a simple multimeter cannot measure the quality of the earth rod. The device you need is called a telluromètre in French.
If the wallbox just stopped sundenly to work, it might be related to a bad earth.
@Xmartin do you have details about your earth rod? How is it installed, where, what kind of terrain,…?
There’s no standard way, it depends mainly of 2 points:
is the electrician a real professional
what kind of terrain.
Depending of the terrain, it could be a simple rod, multiples, a copper cable below the foundations,…
He needs first to start from the main electrical board, find the earth disconnecting link, and follow the cable… That’s the first step.
Second, I’d borrow/rent a telluromètre or ask an electrician to measure.. I know a lot of installation that are simply crap!
May be the original rod was bad quality and now it has been so corroded that if the ground is to dry, the earth quality goes bad.
finally got the dongle. Now, this is somewhat embarassing…:
While preparing to reconnect the charger to the car in order to test via the dongle, I scrolled through the EVSE application setup, and I realized that somehow the max Amps value had changed from the 22A that I had set to 6A. No wonder the charger didn’t work with min Amps = 6 = max Amps! Dude…
Set it back to 22 Amps max, works perfectly again.
Thanks for your ideas about the earthrod - I have to think of a way to get a better earth loop anyway. Is it legal to extend the existing earthrod with another one on the same earth connection, dug in, let’s say the vegetable garden I water during the dry season?
