ESS system is pushing back to the grid after adding a second MP2

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dylan-hyslop asked Nov 30, '22

ESS system is pushing back to the grid after adding a second MP2

Good day,

I had an ess installation working perfectly fine. It was set to 10W grid set point and we had no issues.

We now added a 2nd MP2 in parallel to the same system.

When doing that we had to clear all ESS assistants on the BUS and then re-configure them.

According to the docs we had to go and add ESS assistant onto each inverter on the system. This we did.

However now that the 2nd inverter is installed and up and running I have noticed that we are now pushing ~370W back into the grid, this is even at night when there is no Solar and the battery is low. This is obviously not an ideal situation.

I have tried increasing the grid set point to 100W and that didnt help either?

What settings could I have wrong here?

ESS ess grid setpoint not reached

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dylan-hyslop commented · Nov 30, 2022 at 09:39 PM

Update, after watching this abit it seems that the grid push back matches the inverter output load? (roughly)

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martin-delp dylan-hyslop commented · Dec 01, 2022 at 12:44 PM

Hi Dylan, is this constant, or only for a brief period of time, say 15 minutes or so? I had an issue where I added a second MP2 and the pair randomly started pushing back into the grid at night/early morning although grid feedback disabled etc. My supplier switched the master and slave inverter around and this solved the issue. Not sure if this could be similar in your case, but perhaps worth a shot? To clarify, the switch-around was done through veconfig.

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Answer 1 · 2022-12-01T13:07:55Z

nickdb answered · Dec 01, 2022 at 01:07 PM

Just to confirm, this is a 3-phase system and you added parallel inverters to the existing 3-phase setup? The system is 100% symmetrical?

Change your phase regulation to individual phase in ESS settings and see if that helps.

What is the age of the existing inverters - look at the first 4 digits in the serial number after HQ - and what is the age of the new ones?

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dylan-hyslop commented · Dec 05, 2022 at 07:39 PM

So no, this was a stand alone single phase multi. Which we simply added a second unit to In parallel. Units are about 4 months appart from one another. But I will check the serial numbers.

Cabling etc was all done symmetrical as per the victron docs.

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