Quattro 48/10000/140-100/100 with Solis Overcharging the battery

Q&A and troubleshooting
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1

We are troubleshooting a system, installed by another company, consisting of 3 x Quattro 48/10000/140-100/100 in 3-phase configuration with an AC coupled Solis S5-GC36K with 18kWp PV behind it. The ESS assistant is enabled and configured with frequency shifting in line with the Solis requirements. Quattro firmware is V556 across the board (2653556). The battery Bank consists of 4 x LBSA 10.6kWh batteries in parallel with CAN communication to the Color Control. The above is a high level description of the system layout.

ESS and frequency shifting works flawlessly as designed with one problem. When the grid is disconnected and the batteries are fully charged with the system in maximum derating, the batteries are overcharged when the grid is switched back on. This is due to the fact that the Quattro’s synchronizes the frequency on AC-out1 with the grid frequency immediately when the grid is connected. After 60 seconds, or the Grid standard waiting period, the AC transfer relay closes. The immediate frequency sync results in the Solis delivering full power to the AC-out1 minigrid which gets dumped in the battery. The battery disconnects itself from the system resulting in battery undervoltage errorson the VE.Bus.

I believe the behaviour need to be changed in the firmware to wait the entire duration before the frequency on the non-essential minigrid is synchronized with the grid.

I need assistance to get this resolved.

2

Any reason the PV isn’t on AC OUT1?
Ac out 2 has a delay after AC out 1 is closed so the grid is already synchronised while it is open instead of being able to sync when grid is enabled again.

3

Apologies, the PV intverter is indeed on AC out 1. I will update the original post to reflect this.

4

If the Solis supports sunspec, have you tried using the new GX sunspec capability to control it via modbus instead?

5

We have not.

It is however an option worth while exploring and we will look into this option. I see that Victron does not list this inverter as a supported configuration option. Not to say that it will not work of course.