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scraggs avatar image
scraggs asked

Flickering fluorescent lights in off grid setup

Hi All
I have finally got around to doing a bit more on my off grid setup and have now got 3 buildings setup but have come across a bit of an issue.
If someone turns any type of motor ie: hoover or drill on the fluorescent lights in all the buildings flicker just once as it's switched on, switch it off and on again and it will flicker once, it appears to be only the fluorescents this is happening to, it's really bad in the workshop which has 8 5ft fluorescents ( I will get around to replacing these at some point)
At the moment the setup is being charged from a generator, AC Fronius should be being installed tomorrow.
Setup is
Victron Multiplus2 8000
48v 930a/h traction battery bank
smartshunt 500
Cerbo GX
Cabling from battery to inverter is 2mtr long 2 x 70mm2 for both pos and neg as per spec in manual.
It's like there is a very slight voltage drop happening, then very quickly recovering. this is happening even with a small 500watt motor.
Anyone have any ideas ? I have had a good search through the site, I will put a meter on the ac out tomorrow and see if I can get some idea of what is going on.

Multiplus-II
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3 Answers
johanndo avatar image
johanndo answered ·

Probably caused by the inrush current of your motor.

You cannot do much about it, you could use a VFD to make a soft start and prevent the spike on the line...

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scraggs avatar image scraggs commented ·
Thanks for the reply

I wondered if that may be the case.
probably about time they were all replaced.


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fantail avatar image
fantail answered ·

A hand meter will not show what is going on. The changes are to fast. If you are running off batteries alone you may find a slight voltage drop on the DC input side ( depends on your battery state and type - ie. lithium-fe are slower to respond than Lead acid). With generator running you should have no problem and also when solar PV is charging the batteries - the charge current is just diverted to the inverter to cover the inrush needs of the motors and then back to the batteries. Soft start is one option that will improve the out come for EACH device. Adding a means to handle DC surges on the DC bus improves all devices from one point.

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jeroen-kuijf avatar image
jeroen-kuijf answered ·

A Super capacitor module directly on the DC terminals of the Multi will take care of the voltage dip of your battery.

Be aware to buy a 60V or more capacitor module in your case.

Check vrm, www.quintacasadafonte.com

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