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Kitaigorod Alexandru avatar image
Kitaigorod Alexandru asked

Low humming comming from Pylontech US5000

Hello,

I just installed a system with a MultiPlus-II 48/5000/70-50 and a Pylontech US5000.
They are in separate locations, meaning there is a door dividing the inverter and the battery. I started noticing a low humming noise coming from the battery (similar to the one made by the inverter, but not as loud). Maybe it was there from the start and my excitement drowned it out. Since they are divided by a door, I can tell the noise is indeed coming from the battery, not the inverter.

I measured it with my phone, it reads 38-39db with the Multiplus in "Inverter Only" mode and 42-43db with the the inverter in "On" mode (even though I have enough PV power and don't pull more than a couple of W from the grid).

If I turn off the Victron switch which I have on the plus cable leading to the battery, the buzzing goes away (battery still on).

Is this normal behavior?
Note: The first two days, the Pylontech battery was not connected to earth (if it makes a difference). Now it is.


EDIT: https://streamable.com/6dk9uw (a video with it)


Thank you.

Multiplus-IIPylontech
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Alexandra avatar image
Alexandra answered ·

@Kitaigorod Alexandru

Look up dc ripple.

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Kitaigorod Alexandru avatar image Kitaigorod Alexandru commented ·
Thank you for the reply. I am very much a beginner, but using a multimeter set to AC mode, I measured the battery and got ~0.002V - not sure if this is accurate.

Couldn't find a graph in VRM to check the DC ripple and in CerboGX, the "DC Ripple" alarm status is "OK". Will maybe get a MK3 USB adapter to connect to it with VEConfig and see what is displayed there.

I got no errors so far, even when charging the battery with ~4200W (~82Amps) from the SmartSolar 250/100.

The cable length between battery and inverter is 5m, using 35 mm2 cable and the battery capacity is 100Ah. Which is right at the limit, if I am not mistaken.


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Kitaigorod Alexandru avatar image Kitaigorod Alexandru Kitaigorod Alexandru commented ·

Found a metric with MQTT for the VEBus device under Diagnostics: UBatRipple with the value: 0.14. Is it right to assume this is low enough and shouldn't be cause of concern? Regardless, can this be the source of the humming I hear and if yes, is it normal or should I consider RMA it?


Thank you

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