EVCS Automode Not Working Properly

Q&A and troubleshooting EVCS
1

Here are my settings:

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Late in the afternoon when I don’t have any excess solar, the EVCS keeps trying to charge my car. It will repeatedly start and stop charging within a few minutes or even seconds. This is all occurring around 91% SOC. How can I keep it from doing this quick on and off charging?

2

Can you share more about your equipment and your vehicle’s charging needs?

eg a quick look at your settings suggest that when the batteries exceed 90% SoC it starts charging the car as expected.

But then it draws power - likely drawing down the batteries.

So how much battery capacity do you have? How much is the car drawing? How much non-PV power is available?

e.g. EVCS input of 28A * 230V = 6.5kW, which assuming battery side is 48VDC 100Ah and 100% efficiency is 134A, with 80% DoD, that would last about 35 minutes at best.

3

I have two Multiplus II’s providing 120V and 240V, Cerbo GX, four 100AH SOK 48V batteries.

The 28A is not an EVCS setting. That is the AC In limit set in the Multiplus II’s.

The EVCS does start charging at 90% as expected. That is when solar power input to the battery typically slows down. Most days that occurs around 2pm to 3pm. At that time there is plenty of excess solar to begin charging the car up to a max of 13A. The problem starts late in the afternoon, when there is no excess solar. The EVCS will stop charging the car for a period of maybe 10 minutes and then cycle on and off for periods lasting seconds to a few minutes.

Since I have “Allow battery/grid power for auto mode” disabled, I would expect Auto Mode to sense or calculate via algorithm that there is insufficient excess solar and stop charging for a substantial period (say 30 min) before checking in again to see if there is excess solar. Rapid cycling of charging seems like a failure of the Automode algorithm.

4

Firmware versions in the EVCS, GX, MP IIs ?

5

and what car is it?

6

All on most recent firmware versions. 2026 Hyundai Ioniq 5.

7

Thanks for the info. Some ideas that might help (although you’ve probably already tried):

  1. Enable manual CP Calibration - you could do this and see if it makes a difference. Section 6.1 to enable Manual calibration instead of automatic:

https://www.victronenergy.com/media/pg/EV_Charging_Station/en/troubleshooting.html#UUID-08f76853-124a-0e78-fd7b-0ae95bb0933d

  1. If you temporarily enable “Allow low excess solar power for auto mode” (Which will draw power from the grid to make up the difference from the 1.4kW needed vs what solar is giving you) how does it behave? Just trying to eliminate the communication between EVCS and Ioniq as a factor.
  2. Are all the mechanical connections good and solid? Nothing loose, no problems with the connector seating?

Good luck!