EP600, on "grid parallel" with two EP600s, AC-PV charging does not work as expected

Product Discussion BLUETTI EP Series
1

I have been using 2x EP600 in “grid parallel mode” for a few days, but I am not satisfied with the PV charging (only AC mode).
In single mode (1x EP600), the AC PV charging functioned in automatic mode, without “charge from grid” and activated “time of use”. As soon as the inverters supplied current in AC mode, the charging of the batteries started.
Now with using two EP600 in “grid Parallel” mode, the charging of the batteries will not start after the PV-inverters starts working. It looks like the EP600 are waiting for something.
The PV-Inverter is starting and supplying the house consumption, the rest goes into the grid but nothing into the Batteries!
Only after “charging from grid” and “time of use” have been activated does the charging of the battery start.

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After some time (approx. 30 min), I can deactivate “charging from grid” and “time of use” again and the battery continues to be charged only via the PV modules.
Every day this game starts all over again, only after activating “charging from grid” the battery starts charging, not with the PV power alone.
This is not the same behaviour as in single mode.
With this error, I still have to charge additional grid current into the battery in order for the charging process to start at all, despite sufficient solar power.
Is there a solution for this, or is it better to simply operate both EP600s side by side in single mode?

2

@SigiKa I have conveyed your situation. Our technical engineer, Mike, will help you remotely monitor and resolve this AC PV charging issue through WhatsApp on a one-on-one basis.

3

After some chats with Mike and calibrating the batteries 2 times by setting SOC to 0% - 100% and full discharching and charching the batteries, my “grid parallel configuration” works well the last weeks.

It seems that the start of AC charge depends only on the current on Phase A. I use several micro inverters, each feeding into different phases and they aren’t symetric, depends on witch PV array has the most solar radiation.

Randomly I used the “lowest” micro inverter (north field) on Phase A and the AC charching wont not start as expected. Last week I reorder the assignment of the micro inverters to the tree phases and connect the inverter with the highest performance on Phase A (east field starts first on the day).
Now AC charching starts immediately with starting of micro inverter “A” which supplies the most current early on morning.