question

ccc-telecom avatar image
ccc-telecom asked

Fronius switches off when generator starts = loss of battery charging power

"How can I continue to use the AC Coupled Fronius Primo/Symo to generate solar power when the selected Quattro input is not configured as a grid but is configured as generator, or do I have to accept that it switches off which seems to fly in the face of the Fronius microgrid strategy and documentation about being able to use a fronius OFF-GRID with a generator

>>> Without a solution I will have to remove solar panels from the Fronius and put them on a Victron MPPT which means more Victron MPPT or bigger generators in every configuration we install <<<

This applies to both the ESS Assistant (Main Utility Power Connected zero feed in) and the PV Inverter Assistant (no Utility Power - Off Grid), when the generator is started during the day to charge the battery the fronius switches off

The generator is required to charge the batteries, hence the loss of Fronius power is a problem, hence how do you set the Victron (float voltage / frequency shifting parameters) and Fronius to prevent the rejection of the Generator as an input source for the fronius . . .


Everything works well when Generator is off, on an ESS works fine with Grid until the generator is started and when used in an Off-Grid configuration all works until the generator is started, in both cases the Fronius switches off, the off grid is an high quality 3-phase 30kVA generator

ESSGeneratoroffgridFroniusquattro 10kva
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

3 Answers
Michelle Konzack avatar image
Michelle Konzack answered ·

Simple answer: You can't!


If you start the Generator, it pass-trough the power and is probably not frequency stable enough, hence the AC-Coupled Fronius can not cope with it and shoot down.


Maybe you should check this first.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Marc Heymans avatar image
Marc Heymans answered ·

It is most likely to do with the frequency output of the generator not being compatible with the Fronius

I dont know Fronius that well, but maybe you can look at the frequency of the generator input and then adjust the Fronius accordingly


2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

mjs500 avatar image
mjs500 answered ·

3-phase 30kVA generator with type engine speed governing electronic class A2 i.e. control pack with mag pickup with actuator to control engine speed or class B1 mechanical speed governing

Do you AVR fitted as part generator alternator


CLASS 2 CLASS 1
Frequency 1.5% 2.5%
Voltage 2.5% 5.0%
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.