3-phase 3kva + Growatt 8KTL3-X with ESS not working

Q&A and troubleshooting
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1

Hi guys,

I’m having trouble with a recent install i did. I have the following setup;

  • 3x 3kva multiplus 2 ( 1 per phase )
  • 2x 15,7kwh JK-BMS controlled batteries, 314ah per battery.
  • Growatt 8000TL3-X on AC OUT 1 ( with EM24 meter installed )

The system is working perfectly fine, untill i discconect the AC IN and go in micro-grid mode. The PV inverter then connects to the grid, starts producing and then suddenly after around 20 seconds stops producing, lights flicker, frequency rises and the MP2’s makes a weird noise. Then suddenly the PV inverter starts producing again and all is normal until after 20 seconds it happens again and again and again. I understand the system is using frequency shifting to controll the output of the pv inverter. However, the batterys are only 16% and there is no load on the ac out.

I cant for the love of god figure out why the system is frequency shifting while the batteries are almost empty and there is no load on the AC OUT. For some reason it looks like it cant handle the output of the pv inverter. It doest matter if the pv inverter is outputting 300 watts or 3000 watts. I’ve tried adjusting the frequency settings in ESS and the pv inverter.

Anyone here who can point me in the right direction? I’ve had multiple installers take a look at the settings, but no luck.

2

Hi Kevin,

What is the attached PV size?

The Multiplus 2 3kVA charger is max 35A, (=2016W@57,6V) so less than the MP2 inverter part.

Also, is the max charge current of the batteries perhaps limiting?

3

The attached pv inverter is a Growatt 8000TL3-X. However the problem occurs not at max pv output. It happens in the morning at 300 watts of solar output and at 4000.

the charge limit is set to 120 amps.

4

Did you get to the bottom of this? I have a similar PV inverter and will be adding a MP II in front of it in the new year.

5

We also had some trouble with ac connected growatt. Never got it working correctly. We’ve exchanged the growatt with a fronius and everything works as expected. For that reason we never used growatt again.

6

And Updates on that?

Im currently facing the exact Same issue with my Growatt. Doesnt make Sense at all… (if battery not full)

What was your conclusion / work around?

Today I managed to contact Growatt directly, they will also try to find a solution..

7

Hi Jens, Can you explain what the issue with Growatt was? Did it create reactive power in offgrid mode?

I’m still trying to get it to work.

Support from Growatt just said “Not suitable and not tested in offgrid mode”

8

Sell the Growatt.

I had a fronius 3 fase inverter, now I have only 1 Multi RS 6000, on wich all 18 solar panels are connected, yes 1 phase for the whole installation: heatpump, 2 small boilers, large induction hob and more, everything at once on full power is not possible however.

9

Well.. I installed the 3xMP2 5000 and the big battery in Order to respect factor 1 rule and to have my 14kwp Growatt PV running on backup, so not really answer I was looking for..

plus, I have 24 modules on my west roof in series, I guess there is no Victron out there which could handle ~1000v DC / 9kwp in one string :disappointed_face: I guess I will need to live with non-backup pv or switch to fronius …