We are off grid system installers, having fitted a number of Victron systems on-grid, off-grid with and without generators. In this case, we have an off-grid system installed on a farm, compromising of the following;
3 phase setup with 2x 48/15000 Quattro per phase ( 6 units total )
2x MPPT 450/200
2x Fronius Eco 25kW
24x Pylontech US5000
Cerbo GX
System works flawlessly, charging / discharging, even under loads of 40kW. Until the generator starts. While the generator is running, the charge current fluctuates ( reading from Cerbo screen on Quattro page ) by around 100a constantly. This causes the generator to run poorly and it often cuts out or causes fluctuation of the voltage on AC Output.
All systems are up to date, every setting has been checked and compared to the other systems we have installed working correctly and there seems to be no obvious reason why the charge current should fluctuate the way it does. We have also tried turning the Pylontech BMS control off, DVCC settings all off just to see, but it continues to fluctuate the charge current.
Does anyone have any other ideas on what may be causing this fluctuation?
It’s a 200kVA generator, reasonably new and well serviced. If I drop the charge current down to less than 10a through DVCC the generator will run fine, covering loads no problem.
Fronius are controlled with frequency shift, set up with PV assistant. All settings triple checked.
Even if the fronius is off it will still fluctuate, we just can’t understand it!
How high is the frequency of the generator when you are under 10A charging current?
And what is the frequency curve if you do not set it … does it fluctuate a lot depending on the load?
In which SOC area of the pylon techs does this happen? Always ? or have you looked at the charging parameters of the Pylontech … CCL , CVL ?
What charging voltage do you use via the ‘charger’ setting of the Quattros …
Input 2 used for the generator ?