Victron Multiplus - inverter assist

[[2574]]

I’m intrigued as to why my Victron Multi provides inverter assistance to supply a sub 16A load when the max shorepower draw is set at 16A. See image:

16A @ 240v is 3,840W yet as you can see the “Assist” function is starting well below the 16A shorepower limit. Why would it do that?

 

[jwfrary]

It's normal behavior, the consumption figures displayed are actually a best guess by the system anyway and not an actual value to be relied upon. In addition the actual voltage at the input will also affect the result and how stable the frequency is, its quite a complex system of algorithms involved here.

 

[jwfrary]

To further add to that short response!

The power displayed on the gx device, in your case a cerbo is read from the Ve.bus. The data displayed is an average over a period of time, which is a few seconds or so. It's long enough that it can mislead you into thinking that the inverter hasn't experienced a spike over the input threshold. It is possible to log more grannualar data using graphana or whatever but this also has limitations.

The actual number measured by victron is based on a number or internal measurements but also so fixed assumptions which are a little variable. So the value is in the Right ball park, but may not be a precice reflection of what's actually going on.

Your wattage calculation is based on the voltage being 240, that's barely ever the case exactly. Also bear that in mind that the inverter will also base some things off the output voltage selected which may be 230v.... It will still work with 240v but when you disconnect the input then you will find the voltage gradually drop away to 230. If it is set to 230 then its 3680VA that it will start to power assist at. This is easy to change.

I assume this is with a multiplus and not the multiplus 2. The latter has an ac current meter which has its own problems on the early models.

 

[[2574]]

To further add to that short response!

The power displayed on the gx device, in your case a cerbo is read from the Ve.bus. The data displayed is an average over a period of time, which is a few seconds or so. It's long enough that it can mislead you into thinking that the inverter hasn't experienced a spike over the input threshold. It is possible to log more grannualar data using graphana or whatever but this also has limitations.

The actual number measured by victron is based on a number or internal measurements but also so fixed assumptions which are a little variable. So the value is in the Right ball park, but may not be a precice reflection of what's actually going on.

Your wattage calculation is based on the voltage being 240, that's barely ever the case exactly. Also bear that in mind that the inverter will also base some things off the output voltage selected which may be 230v.... It will still work with 240v but when you disconnect the input then you will find the voltage gradually drop away to 230. If it is set to 230 then its 3680VA that it will start to power assist at. This is easy to change.

I assume this is with a multiplus and not the multiplus 2. The latter has an ac current meter which has its own problems on the early models.

Interesting and helpful, thanks. Yes a 120A/3kw Multi.

 

[jwfrary]

Interesting and helpful, thanks. Yes a 120A/3kw Multi.

Great units, I have quite a few in service at work and they are all a tiny bit different but not dramatically so and are very reliable.

Another thing many don't spot is by default they are set to 75% charge current.

 

[[2574]]

Great units, I have quite a few in service at work and they are all a tiny bit different but not dramatically so and are very reliable.

Another thing many don't spot is by default they are set to 75% charge current.

I’ll check that!

 

[jwfrary]

I’ll check that!

You will need a mark 3 device or if your system is connected to the internet and VRM you can do it via victron remote configuration.
If your struggling ill walk you through it.

 

[[2574]]

You will need a mark 3 device or if your system is connected to the internet and VRM you can do it via victron remote configuration.
If your struggling ill walk you through it.

Yes, on internet and VRM though I’ve not used Remote Config, I assume that’s different to Remote Console?

 

[vas]

Robih, you can have more info on the screen using kwindrem GuiMods (kwindrem - Overview):

this is mine now (slightly confusing as battery shown is the LifePO4 bank which is off, currently running minimal loads from the old Trojans.
gives v, a and hz which is handy when checking things out.

V.