Earlier today I was charging my car from PV, but I had to use the car, so I stopped the charge, and went on my drive.
Then when coming home I plugged the car in again, heard the contactor close, but MPPTs are idle.
There is solar available, but it isn’t using it, not even trying to sustain house consumption either.
What can be wrong?
All fuses are fine, no errors… and suddenly everything started working again.
EVCS load is included in the AC Loads reading.
Kinda working… Something isn’t right…
EVCS is set to start at 95% SOC, so it starts… then as soon as it starts, it starts counting down for stopping, then starts charging again. Looks like the problem could be DESS. It estimate the battery to be at 100% right now.
So the charger starts because the battery is charged, stops because PV is too low, starts again because battery is still charged…
EVCS load is included in the AC Loads reading… 
Does the DESS possibly prohibit unloading?
Yes, I think that was the initial problem.
But for some reason something decided to also disable MPPTs because the battery was full, while ignoring the rest of the load on the system.
And because DESS wouldn’t allow discharging of the battery, EVCS kept turning on because of high enough SOC, but also turning off right away because of just charging from grid… just to turn back on again because of high enough SOC.
Been looking at the settings for the EVCS, and in auto mode, I don’t see a way to prevent this from happening again. It could turn on every 60 seconds, just to turn off again after 120 seconds, just to turn on again. That would be pretty horrible if not detected.
Well, DESS can decide to set the battery idle (sometimes), when grid is cheap and it expects to can use all the battery capacity at more expensive hours.
The game then goes like:
In other words, you have two automations fighting on contradicting flow-goals. That won’t work well sometimes.
Either configure the EVCS to not use battery, or disable DESS, while you want the EVCS to be able to do that. (Shortcut to that is just in the VRM Menu bar, bit bellow EVCS control)
Yes, but then turning off after a minute, just to then turn on again 30 seconds later, should be prevented. One solution would be to disable DESS, but if it needs to be done manually every time the charger is active, there is a very high chance it will be forgotten, and then it is back to turning on and off over and over.
A bit more logic should be added, to determine if it is actually allowed to use anything from the battery.
There also isn’t an option to only not use battery, it is only “Allow battery/grid power for auto mode”, and it should be allowed to use grid to supplement if needed.
For now I have added some more automations in home assistant to control the start/stop, so if it turns on, just to turn off again. The charger will be stopped and the auto mode will be stopped with “Waiting for start”. I would rather lose a bit of solar energy, than turning the charger in the car on and off over and over.
