OpenEVSE charging rate shows wrong

[Tonza (Toni Kähkönen)]

OpenEVSE charging rate is always 3A more than what the car actually charges. I can tweak this via RAPI but the charging starts only when the 3A lead distance has been reached and the kWh calculation also gives too large numbers apparently for this same reason?

Does someone how to fix this?

OpenEVSE
Firmware:8.2.2.3P

OpenEVSE WiFi
Firmware config:openevse_wifi_v1
Firmware version:4.1.7

Tesla

[Stu_A]

Hi Tonza, welcome

I had a similar issue with my Leaf not responding to the calculated pilot signal in OpenEVSE. I wrote some external control software to manage the openEVSE pilot signal and soak up excess grid power rather than rely on the internal PV divert function. You can find the thread and links to GitHub here:

Nissan Leaf; Pilot signal not being followed

Hi all! Have just taken delivery of my EmonEVSE unit in order to charge my Leaf from excess solar PV output, replacing a dumb Rolec wallbox. Pleased so far with the unit, however I have noticed now we have some actual sunny days that the car does not seem to follow the pilot signal properly. Most noticeably it either cuts off when the pilot drops below 8A or charges at full power regardless of the pilot value when charging comes on. PS: Max charging limit is set to 15A presently due to temporar…

I don’t actually know if this is an issue with the car or the OpenEVSE or it’s just ‘normal’ . It doesn’t matter since the software forms a closed loop feedback path to overcome any offset issues like this. So long as changing the pilot causes the actual consumption of the vehicle to change in the same direction it should work. When the car decides it has had enough and stops charging the pilot will just float up to max and stop there. Which is fine since this is what a fixed output wallbox would be like anyway. I also included just turning charging on and off into the software e.g. for night time charging.

Stu

[Tonza (Toni Kähkönen)]

Hi Stu, thank you.
It’s nice to hear that I’m not alone with this problem , but I’m not in my comfort zone when it comes to programming. I hope there is an easier solution for this or I’m just suffering with this…

[fraz]

What car do you have? I’ve noticed BYD would draw something like 8A when using the Polestar 10A EVSE, or Khons at 10 or 15A; Always a couple of amps less. It wasn’t an EVSE problem, just a quirk of the car. You might have to builld a fudge factor into how you transmit the solar PV data. How are you doing that?