Clicking sounds near relays in MultiPlus II unit

Hello Victron Community,

I have a Victron MultiPlus-II 48/5000/70-50 230 V (serial number: HQ22174VWQGU ) unit and I’m experiencing the following issues:

  • I can hear frequent irregular clicking/popping sounds coming from the area near the transformer or power relays (hard to precisely find),
  • I suspect voltage fluctuations on the AC output,
  • Using a thermal camera, I’ve found that resistors R83, R27 and R26 are overheating to above 50 °C,
  • These resistors are marked 753 (75 kΩ) and are located between the relays above AC out and AC in.

The unit is otherwise working, but I’m concerned this may indicate a failing relay or other problem and could eventually damage the inverter.

Have others experienced this issue?
Do you know how to diagnose it more precisely and what elements should I check/replace? Any help would be very appreciated!

Hi contact your victron dealer, its still under warranty

Hi Marc,

thanks, I know. The problem is I’m leaving my home in a week time for my almost 3-weeks holidays and my dealer is not able to visit me before it… This sound worries me as I dont know if this is risky or not. Of course I can switch my Victrons off and rely only on grid, but I’ve got some IT servers which need uninterrupted power, that was my main motivation for my energy storage and Victrons, so both options are risky for me from different perspectives.

That’s why, leveraging my technical background, third option is to use that couple of days and try to at least diagnose it to find out if I can leave it safely for my holidays, or I need to shut my Victrons down.

I compared my thermo camera view with the same MultiPlus unit which is next to this one, and looks like those resistors I mentioned before are not overheating, looks like normal temperature (~50 degrees), as the thermal view is exactly the same for both units, I cannot find any difference.

I’m attaching video, where you can hear those strange “clicks”: https://youtube.com/shorts/T33cvettmKQ

Youre right, Thats doesnt sound ok…

And I forgot to mention - the “clicks” can be heard only when there’s load attached to AC-out… when output is disconnected from the installation (but still e.g. charges batteries), no clicks…

Could this be the multifunction relay that is enabled and disabled by some value?

Hi chirgu,

that’s also my hypothesis, but (surprisingly) I cannot find a good way to localize the sound source. I can hear it in almost every place in a unit with the same intensity… :frowning:

P.S. I’ve got good oscilloscope, but no diff probes, so I dont want to risk damaging it. I’ve got good multimeters too, but not sure what to measure and where…

You said you suspect fluctuations on the AC output, why don’t you measure those precisely? You could use the VRM figures.

Hi Fideri K,

I suspect it, as I can hear very similar sound effects with the same frequency in my electric oven in my kitchen, so I think there are some voltage drops/spikes which go to the load.

I tried to measure it with multimeter, but I think those drops/spikes are too fast and I cannot see it in multimeter.

What VRM figures you are referring to?

I’ve got Victron MK3-USB interface and Victron software (in fact I configured those devices couple of years ago by myself). Are there any logs I could look into? Standard Color Control GX doesnt show any errors…

You used VRM advanced widgets? If the fluctuations are very brief, VRM may not capture them.
As part of diagnosis, I would try out each relay (the number of relays is documented somewhere) by enabling and disabling it with assistants.

Just checked all advanced VRM widgets, nothing interesting… Relays with assistants - do you mean to use VEconfigure with assistant which is able to check individual relay? I’ve just found “Relay locker” assistant, should I use it to enable/disable each relay?

Update: I’ve installed Relay locker assistant. Can I safely disable/enable each relay when system is running? Or should I do something before, e.g. disconnect loads, PV?

If an input relay was faulty the system would report it.
The effects would be more obvious.

Hi Nick,

yes, that’s true. On the other hand there are many more relays in a unit, and maybe one of them is very quickly shortening/opening? Or even input relay if opened for couple of milisecs, would it be detected by system? There’s a list of relays in Relay locker assistant, so my plan is to lock each of them for 60 secs and in this way I may be able to find which one is generating “clicks”, if this is the source of the sound… However, not sure if it is safe to lock each relay when system is running. Should I do some precautions, e.g. disconnect PV, batteries?

If you are certain it isn’t a sound being triggered by a specific load, I would return it for a bench test or replacement.
It isn’t worth the risk, and even if you could narrow it down to the specific component, there isn’t much you could do to resolve it yourself.

Yes, I know, but if this is caused by some “not very important” relay I would leave it “as is” for my 3-weeks holiday, otherwise I would need to shut down victron and energy storage, which in turn would expose my IT servers for a risk of unavailability, while I would be far away from my home “data center”… I also know how to solder/desolder stuff, so would be the option as well once I know which component fails…

In the end of the day - you are absolutely right, it’s much more reasonable to return it for test or replacement, but my “DIY soul” just tells me “try more…” :slight_smile:

Understand. Good luck, hope you find it.
There used to be a pre RMA test document that had some procedures you could try yourself. These seem to have disappeared with the new website upgrade, maybe someone still has a link.

Thanks Nick!

That would be great to have it, anyone can share?

Many thanks Nick! Nothing about relay locking in the document, so my plan is disconnect device from installation and start checking relays one by one. We will see…

Not too much progress, at least using headset and sensitive microphone, Im almost sure that sounds are coming from this grey element, probably relay. It’s very near to the output of toroidal transformer. Not having board schematics its not easy to guess…

Still looking for the reason…