mikepaterson avatar image
mikepaterson asked

Multiplus ESS LED Meanings and Overload Issues

I’m looking for some help with my set up. My ESS system (details below) has been very stable but has recently been giving overload errors and I can’t interpret the light sequences on the front of the Multiplus unit.

Let’s start with the Multiplus LED lights. I’ve searched all of the following combinations in the Victron Toolkit app, and none of the combinations appear to match what I have.

In apparently normal operation:

  • The yellow bulk light stays on constantly – no flashing.
  • The green “Inverter On” LED flashes as one would expect - when the inverter is running in power assist mode. It is never shoing as solid green. Off or flashing only.
  • However, I cannot understand the behaviour of the green “Mains On” LED which does not appear to have any pattern to whether it flashes or stays on solidly. During the day when there is some solar PV input the light may appear on solidly, or it may flash. At night when there is no PV and only Powerassist the LED may stay solid green for a minute or two, and sometimes it may flash once and return to solid. The flashing may continue and be irregular, or it may be pulsing in time with the “Inverter On” light.

How do I interpret the various states of the “Mains On” LED light? One combination that the Toolkit suggests is that when both greens are flashing (ie Mains On and Inverter On) then this is “Feed-in with PV Power”. But that doesn’t seem consistent with there being no PV at night.

And why will it alternate between solid green and intermittent flashing during the day when there is some PV?

Is the Mains On pattern related to the Grid Set point? Eg it will flash during minor exports of power? I can’t see a connection between the feedback into the grid and the state of the “Mains On” light

Or is it as one of the errors states suggests, a symptom of some form of “Pass through or mains-rejection”?


Is this light pattern in any way related to the other issue, “Overload” errors? There is no pattern to these other than they are becoming more frequently – almost daily now.

The first strange behaviour is that it gave an Overload error during the middle of the night when the batteries were being recharged from the mains on a timed recharge. The error appears to have been temporary as the unit did not switch off or go in to a ‘limp mode’

Following other When I try to reset the Multiplus unit by switching it to off for 30 seconds and then back to ‘on’, I sometimes get a rattling/vibration noise from the Multiplus and the lighting circuit (ie the critical load circuit) flashes at the same frequency as this vibrating noise from the Multiplus. The vibration may last a few seconds and then the unit switches off. The red overload button is flashing during this time also.

The unit might not reset properly until it has been left in Charger only mode for maybe an hour.

At other times, I have what appears as an overload error, and the Multiplus appears to be in a sort of “limp” mode, where the Inverter will only supply about 100W when the demand is clearly much higher, but there is no continuing “Overload” red light. The same “reset” noises as described earlier may occur.

I’ve checked all of the connections in the Multiplus and the mains distribution board to make sure they are tight. The Cat 5 cable between the Venue and Multiplus has been replaced to give certainty. Victron Connect has been used to ensure the latest firmware, and the right UK set up.

I haven’t tried to switch off the “Loss of Mains” detection to see if this helps as I understand this is only a very rare error for long supply lines.

So, is there an error in the set up? Are the Multiplus light patterns connected? Or does the vibrating noise sound like something is broken?

In each case Overload situation the batteries were well charged, so I didn’t think there was insufficient voltage to perform a relay test

Set Up:

A very standard domestic ESS single phase sytem. Standard 3.6kW PV array with a separate inverter generating mains voltage connected to AC input. A 5000VA Multiplus (ID 2624), 5 x Pylontech US3000C, with a Victron Venus GX controller and Carlo Gavazzi ET112. All on the latest firmware: 508 for the Multiplus, with the latest (as at 06/02/2024) ESS Assistant, and 3.14 for the Venus. The Multiplus Firmware is confirmed as UK/G98 settings. All the standard Pylontech /Victron set up has been followed exactly.

I have what I understand to be a very stable, modern suburban supply. There are however 8 3.6 kw PV systems in total in the same small housing estate, with three Battery systems across those 8 systems.


Thank you in advance for any advice. I am happy for the Victron team to read the system on line.

ESSPylontechmultiplus ve.busRelayled
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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·


Some LED codes are explained in the manual and there is the Victron Toolkit App to look for the LED codes.

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Alexandra avatar image
Alexandra answered ·


With a GX in the system, you don't really need to know what the lights mean. The GX will tell you if there are problems.

You can see the ve bus state on a widget in the VRM advanced section.

It is easy to see what the system. Is doing - charging discharging, power assist or not.

The overload during charging will be because the unit is getting hot. You do get derating with heat.

The other possibility is there is a problem in wiring.

A neutral line mix up or an appliance that is leaking line to neutral. This can also cause relay clicking - weird some wave and overloads.

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