Flickering lights issue with Fronius Primo's AC Coupled

DIY
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1

I have just installed a Quattro 15000VA inverter with 3 Fronius Primo 5KW inverters, 1 250/100 MPPT charger, 4 15KWH LiFePo4 batteries using JK V19 Inverter BMS and a Raspberry Pi running the latest version of Venus OS. The BMS is connected to the Raspberry Pi via CAN and DVCC is turned on with SVS and SCS enabled. This system is off grid and ATM nothing is connected to the AC inputs on the Quattro.

Everything works perfectly except when there is low power coming from the Fronius inverters, it is then that I have lights flickering due to the fluctuations of the AC voltage. When this is happening the Quattro is making noises in the transformer reacting to these fluctuations. It is NOT a LED light fault, the flickering lights is a symptom of the issue with the AC voltage. It is the same as this thread Fronius Flickering on AC out - reactive power settings? Up until now I have been using an off grid inverter that I built myself with the same 3 Fronius inverters running for a very long time and never had any issues. The only change to the Fronius inverters is to change the country code from Australia to MG50. Previously I was regulating the PV input to the Fronius inverters to manage battery charging. So I am doubtful that there is a hardware issue with the Fronius inverters. The issue occurs only at low PV power levels, when frequency shifting is occurring everything is running smoothly. If I turn off one of the Fronius inverters when it is playing up it will either stop fluctuating or reduce to a much lower level of fluctuation.

In this thread it mentions loading firmware version FW fro35069.upd that resolved the issue. I have contacted a Fronius Partner I know and he has asked Fronius for this version of the firmware but they say it is unavailable.

If someone has this firmware version or another solution it would be greatly appreciated.

2

If anyone has the light flickering issue, Fronius have told me the latest firmware includes the update mentioned in the previous post. I was running the latest firmware which was working fine with one PV inverter, but with 2 it was causing mild voltage fluctuations and with 3 PV inverters running it was much worse. The fluctuations were not happening when there was full sun, just at lower power levels. Fronius have given me some changes to make to the settings and that seems to have resolved the issue.

3

It’s been a while since I’ve been onsite during sunset but I have (roughly) the same setup and the exact same issue: flickering (LED) lights when the inverters try to squeeze the maximum power out of low light conditions and AC voltage fluctuates.
Regular Victron Multis here and 2x three phase Fronius Symo Advanced inverters that run in MG50 mode and have firmware fro36120.

Can you share the parameters that Fronius gave you that resolved the flickering ?

4

I am not sure if I should be sharing the settings publicly or not. Is there a way to DM you? Otherwise might be worth contacting Fronius.

5

You could try guessing my gmail address, it’s not hard :wink: