I bought a well-made Chinese charger for our Zoe ZE50 R110 electric vehicle.
It can be set to various charging levels (8,10,12,16A at 220V), but as a safety (I guess), the procedure requires me to disconnect the cable from the car before I can change the charging level.
Here is the interesting part : since I live offgrid, I wish I could change the charging level automatically with a microcontroller according to actual solar panel production (or production leftover).
The deal is to simulate disconnection of the EV plug.
I am not sure what kind of relay would be OK. I feel like electromechanical relays are safer and lower cost.
I also though about
- disconnecting the charger first on the mains side with a regular AC power relay
- so I can safely simulate disconnection on the EV plug with an almost usual power relay (the cable is no more energized)
- I now reconnect the mains (upstream), no charge so low power
- Now I can set the charging level (hacked charger or with a servo motor pushing on the buttons)
- Eventually I "reconnect" on the vehicle side
However, (5) might still be hazardous ...I fear high power transients could quickly ruin the relay or even put my offgrid home on fire (*).
I understand additional electronics might be needed, or some "partial relay" as shown in some schematics. But I find it difficult to get proper educated info, as it gets drowned in usual charging procedures and numbers.
NB: (*) sure, there are also regulations, but my question here is only technical
Update: also discovered What does an EV "wall socket charging cable" do? which provides lots of info, but which looks like overkill in my use case.