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Philipp Trenz avatar image
Philipp Trenz asked

Overload alert on grid-tied Multiplus-II

Hey there,

since installation we're getting an "Overload L1 on VE.Bus System" alert every now and then on an installation with a grid-tied Multiplus-II 48V/3kVA. The alerts are normally resolved in less than 60 seconds and the statistics within the "Extended" view of VRM do not show any loads which would overload the Multiplus. So I suspect some very short current spikes as the reason for the alert.

Among other things, a heat pump for water heating is connected to AC-Out, and I suspect its compressor as the reason for the alert. To my knowledge, overloading a grid-tied Multiplus would need exceeding 50A from the grid plus the maximum of the Multiplus-II (around 10A?). But can the starting current of a compressor really be that high?

Is there anyone with similar experiences? And if the compressor is really the reason, is there any way to cap the current spike?

Many thanks!

Multiplus-II
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2 Answers
Mike Dorsett avatar image
Mike Dorsett answered ·

compressors do normally have a very high starting current - 6 to 10 x the compressor motor rating. try connecting the heat pump to the AC2 output.

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lifeingalicia avatar image
lifeingalicia answered ·

As said best to wire large start up loads to ac2

Ct driven installs use bat and inverter first then drive the grid up - likely warnings

External meter driven installs work the other way round.


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