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obz avatar image
obz asked

Multiplus 500 buzzing when on grid

Recently installed a new Multiplus 500 into my caravan and up to now I've been running off grid. Before going away I've tried the grid connection and noticed that the Multplus buzzes. It's not loud but is noticable at night. The buzzing does tend to change depending on the 230v load.

I'm now thinking of relocating the in Multiplus which will means longer 12v battery connection but it may mean I can sleep better

Is the buzzing normal as I thought that when on grid the Multiplus was effectively bypassed?

Thanks

Gareth.

Multiplus-II
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Rob Duthie avatar image Rob Duthie commented ·

Hi Obz

Yes they do this, depending on what harmonics are on the mains it can be worse, but normal 50 Hz hum can be heard, Mine is Mulitplus2 and it hums and buzzes depending on the loads etc. This is due to the internal toroidal transformer which they use and the bidirectional converter used. It is a Low frequency design, so is much easy to hear a noise

compared to high frequency designs.

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markus avatar image
markus answered ·

Hi,

you might hear the charger charging your batteries.

The buzzing is normal, I can confirm.

This unit is better not mounted under a bed ;o)

Regards,

Markus

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