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bruce-kirk avatar image
bruce-kirk asked

Unstable Quattro Output Voltage

A client has a Quattro 10kVA inverter which has been troublesome for quite some time in that the switchover time when the grid fails is too slow to prevent items like decoders and WiFi routers from having to reboot. But now there is a new problem.

The AC output voltage fluctuates and causes lights to dim, ceiling fans to slow down and refrigerators to complain. sometimes there is a complete loss of output for a split second. My client measured an output voltage of 180V instead of 230V. Yet VRM Portal shows a constant 230V with no signs of any dip.

I have checked all the incoming and outgoing AC wiring and it is all good with no loose connections or signs of overheated wiring.

Does anyone have any suggestions?

MultiPlus Quattro Inverter Charger
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3 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Bruce Kirk,

It sounds like the grid might be browning out, and the Quattro is tracking that AC input voltage until it reaches the default low cut off value (at 180V).

When that low grid voltage finally does drop below 180V, then it will snap back to the inverter generated 230V - which sounds like enough that it is upsetting the devices.

Try increasing the low voltage cut out value to 205V and the reconnect to 212V and see if this prevents this issue. Note this will mean that the Quattro is taking over from the grid more often, so then the battery and solar also needs to be sized accordingly.

If that fixes the issue, then you can do some fine tuning to find at what point the issues occur, but still maximise grid connection time.

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bruce-kirk avatar image bruce-kirk commented ·

Hi @Guy Stewart (Victron Community Manager).

Thank you, I will try this. However, we have switched the changeover switch to Grid in the mean time and there are no problems so I can't help thinking there may be a fault with the Quattro.

I'll update you after making the changes you suggest.

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bruce-kirk answered ·

Hi @Guy Stewart (Victron Community Manager)

Changing the AC input voltage limits has not helped. The problem is unchanged. Furthermore, the VRM Portal AC input voltage graph is stable between 230V and 245V (if you can call that stable) from our utility. I'm guessing there's a problem with this inverter that needs to be attended to by an authorized repair agent. Your thoughts?

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imo avatar image
imo answered ·

I have this same issue but with a 3phase system installation. The output voltages at the Inverter terminals are reading constant 230v. The vrm portal log also gives 230v output steady on the graph. but the voltage on the load cable differs greatly even with no load

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