drogos avatar image
drogos asked

Quattro making buzzing sounds

I have bought a used Quattro. It seemingly works, but some times it starts to make bad sounds. I tried connecting it with only 50mm dc cables straight to multiple different batteries with no ac connected. Sounds is the same. How ever if it is off for a little it tends to go away again. I made two recordings of the sound: and This is not a wiering / battery / ac issue. Any idea what this could be?

MultiPlus Quattro Inverter Charger
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Alexandra avatar image Alexandra ♦ commented ·

By 50mm² DC cable is right you mean 2x 50mm² neg and pos?

Have you switched on with AC in and AC out disconnected/isolated completely? Does it make the same sound?

Have you measured the voltage output of the terminals? Is it correct?

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drogos avatar image drogos Alexandra ♦ commented ·

Yes, 2x 50mm cable, one neg and one pos. AC output is stable at 232 volts. Both with and without anything connected to them. Sound comes and goes, regardless if there is any loads conncted. Most often it goes away after a power cycle, but not always. The Quattro has no ac in connected, and yes, tested with and without ac out connected.

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Alexandra avatar image Alexandra ♦ drogos commented ·

No loads is not quite the same test as no wiring connected.

Sometimes there can be funny interactions in wiring. So just thought to check.

Had a install buzz weird on a site, eventually replaced an armoured cable in the install (not even directly connected to the inverter). Problem sorted.

Sounds like a bad sine wave related noise. Strange how it comes and goes. Maybe open up the unit and check connections between all the components and boards, particularly the comms board.

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2 Answers
nickdb avatar image
nickdb answered ·

Sounds like a load that has a dodgy power supply that only uses part of the sine wave.

Were any loads connected? It so, what?

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drogos avatar image drogos commented ·
Tested it with both loads connected and disconnected. Tried connecting a freeer, a latop, a pool pump, all the same. Sounds sometimes is there, other times not. Tried with AGM batteries as well as lithium batteries. Also have a Phoenix 3kva on another system. Swapped these, and Phoenix never have issues, Quattro always end up buzzing from time to time.
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Sarah avatar image
Sarah answered ·

Hi @Drogos really hard to tell what the noises could be from. From a troubleshooting perspective have you tried updating the firmware on the Quattro. It may not fix the problem but it rules the firmware out as the source of the issue. Please be aware that doing the update will erase the config of the Quattro.

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