ESS or backup system for weak Grid Main?

DIY
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1

Hello

First of all, I am living in the Ukraine and we do have very bad grid characteristics due to situation in the region.
I have setup victron system with ESS and it works just fine for me, but oftenly fail because of luck of capacity.

Thuse I have recently updated my Victron setup and have a next system:

  1. Gerbo GX
  2. 6x Polyntech US2000c battery of total capacity 14.4 kW
  3. 6x Solar Panel with 540 W, total ~ 3 kW
  4. MPPT 150/35 was updated with the MPPT 150/100.
  5. Multiplus-II 48/3000/35-32 was updated with Multiplus-II 48/10000/100-140
  6. The 11 kW stabilizer on the enter point from Grid to house.

Just after the migration to a better devices I also update the system to the latest firmware versions and I got:

  1. Gerbo GX v3.42
  2. MultiPlus-II 48/10000/140-100/100 version 552
  3. SmartSolar MPPT VE.Can 150/100 rev2 v3.16

Before migration to the newer hardaware setup, my logical setup was like next:
Summer mode

  1. Use ESS with the Optimazed(without battery life)
  2. Minimum SOC level 30%
  3. No charging from grid.
  4. Grid set point 50 W

Winter mode

  1. Use ESS with the Optimazed(without battery life)
  2. Minimum SOC level 85%
  3. Charge the battery over night hours (00:00 - 05:00) up to 100% SOC.
  4. Grid set point 100 W(playing with wider range but got no effect so stop on this one)

And those mode above were working just fine for me as I said.
With the new setup, the new invertor is switching frequently between main and batteries. Whenever it switch to the main it shut down the stabilizer, and so alarming about grid lost.
If I put stabilizer into the bypass mode, it still trying to connect to main grid, sometimes with success some time it just fast switching to it and back to the batteries.

What I have noticed, before even update the configuration with the ESS mode, the invertor was working in the External mode. In this mode, it could succesfully charge the battery with the 5kW and also provide electricity to the house 1kW. I was able manually switch this mode as I could leave it charge the battery up to 100% in the night and provide electricity to the house. In the 06:00 I was switching manually the invertor mode from “On” to “Invertor only” and it works just fine till 22:00 when I again switch back to “On” mode and it charging the battery till 06:00.

Need to mentioned I have reduced the grid currency to 16 A only, because grid failed approximately every 20 minutes with charging about 6kW/hour.

Reading the documentaion I came to conclution that the ESS rely on good current from the Grid.
Whenever I had a lighter setup, it could survive, but with more powerful Invertor, it looks like struggle to switch to main and operate normally.

Questions I have:

  1. Maybe I miss something in setup? I will be happy to provide any charts/configurations needed…
  2. In the tutorial about ESS explicitly mentioned that the ESS will not suppose to work for the weak grid(which I think my main problem atm, I have a few powerful electric motor with 4kW each, so they shutdown the stabilizer at the moment of start but works in bypass mode). Instead he suggest to create a backup system which is allowed to do so with the Victron API. This one looks like DIY project and I do not mind, if it simple could save me manual efforts menioned above, like switching between “On”/“Invertor Only” states automatically with preset time for those operation with threshold of 30% battery in case main grid failed. Is that correct way of thinking? Or should I concentrate on solving issue with ESS?

Other thing I cannot really setup the system without the stabilizer since the voltage range is jumping between 180-250 V and everything keep flickering inside the house.

Thank you in advance