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robertg66 avatar image

2 x MP-II 5k not working in Inverter mode, why?

Hi,

I have 2 Multiplus-II 5k-70 parallel, connected to 6 x US3000, Cebro GX (2.62) and a Fronius Primo on AC-Out1. What I don't understand is why the MP-II stops working when they are connected to the grid and in 'Inverter' mode. They work when connected to the grid and in 'Charge only' mode. They also work when they are in 'Inverter' mode and NOT connected to the grid. Who can help me to find the problem why they don't work when connected to the grid and in Inverter mode? Dealer is saying they configured the Multiplus correct and can't find a wrong setting.

To test and to find the problem I exclude the cabling and the in-house circuit (also the Fronius) therefore I connected the Multiplus's directly from the Main grid circuit breaker to the Multiplus 'AC-In's (cables are same length, no fuses or busbar in between). On the AC-Out1 I directly connected a load (no busbar or breakers). When I switch the MP-II on it takes them multiple tries before connecting to the grid. When and if it succeeds the loading to the battery is very unregular and fluctuating. One of the multiplus is making a unregular fluctuating humming sound. After 2-6 minutes the MP-II shutdown (no error in the VRM portal). Sometimes they restore and sometimes they stay off.

All settings that I know of (from the manuals) are set. 'Limit Inverter Power' is switched off.

I am lost... why does it work in other modes and not when in Inverter mode?


Robert

Multiplus-IIparallel
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A remark, I have the feeling that when connected to the grid the Multiplus's are being limited, hold back. I can see the all the value going up and down. I measured on AC-In the volts fluctuating between 220 and 235 volts.

5 Answers
robertg66 avatar image
robertg66 answered ·

Goodmorning David,

Sadly I don't have a MK3 to read or adjust the settings. The installation was setup by the dealer a few days ago (it's a new installation). They forgot the ESS Assistant what I have done myself (using VRM Portal). The dealer thinks the problems are related to the house installation. Something disturbing that effects the working of the Multiplus. I checked everything and couldn't find a problem. Step by step I want to check and rule out things. The dealer is 450 kilometers away, I asked them to ship a MK3.

When it arrives I will share the settings. In the mean time it's running on 'Charge only' mode.

Robert

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If you added the ESS assistant using VRM, then why do you say you can't see the inverters settings?


From your initial description it sounds as one possible cause could be that you don't have a grid code set.

But if you added ESS, that requires a grid code, so you must have something set there.

Hi,

Sorry, I am under the impression that some settings can't be set when in parrellel mode and an MK3 is needed for the Parallel configuration (VE.Bus Quick Configure).

I can't attach the downloadable .rvms or the .vsc directly. So, I changed the extension to .txt Master (.vsc).vsc.txt , if you change this back to .vsc (delete the .txt extension) than you have the master settings. Is this enough? The slave settings are Identical (checked this 10 times ;).

I also attached the Exported settings, this comes as a text file. Export Master Settings.TXT

No idea what you prefer. Installation is connected to the Portugese grid (EDP).

Thanks for helping me out.

Robert


I was not talking about configuring the inverters, but about viewing their settings.


I see that the master is set with a grid code (Germany). Apparently there is no Portugal grid code option available.


Your ESS assistant appears to not be started.

Also, ESS will need to be installed in the slave inverter, too.


The firmware you have is quite old (475). Any particular reason for that?

Hahaha, you are right about viewing the settings ;)

I tried the following, maybe this helps, what I have done:

  1. Disconnected ALL the house connection from the Main circuit breaker.
  2. Removed all existing AC cables from the Multiplusses on both the AC-sides (AC-In and AC-Out).
  3. Connected two new cables directly from the Main Circuit breaker to both multiplusses to the AC-In. They are the same length and 6mm2.
  4. Connected two new cables from the AC-Out1 directly to a 1000 watt light.
  5. Nothing was connected to the house or the fuse boxes!

They run only for a few minutes and then switches of completely giving an ‘Overload’ ERROR on the Master and two blinking ERROS 'Bulk' and 'float'. It’s was humming irregularly, sometimes I can hear relay’s clicking. ‘Mains On’ light goes on for a few minutes, ‘Inverter’ light goes off after a few minutes. I can see the voltage fluctuate between 223 and 232.

Good question about the firmware, I asked the Dealer about this. I used the VRM portal option to test if new Firmware is needed. Answer was 'No'.

I will look into the ESS not started thing. It is indeed installed on both Master and Slave.

Robert

When starting up the Neutrals from AC-In and AC-Out1 where still connected (my mistake, busbar with multiple neutrals)). It stopped working straight away and I changed this. Can this cause the problem?

Robert

VRM portal can't update the inverter firmware. That method only works for solar chargers, SmartShunt, etc.


The only way to update the Multiplus firmware is via a MK3-USB interface.


Victron addressed some "false overload" issues in FW 478 and then again in FW 481 (this is the latest firmware version right now). You can find these on Victron Professional (you need a free account).

FW481 is also included in latest VictronConnect.


Maybe that is the issue you have, maybe not.

Tomorrow I will drive to the dealer to do the testing and upgrade of the firmware. I am about a kilometer away from the transformer. When I use about 10 Amps the voltage sometimes drops to 205 volts. The lights dim when I switch on the oven.

Also when not connected to the grid all works fine (charging and inverter). Sadly I use so much power that I need to be connected to the grid, else....

Will keep you updated and many thanks!

Almost out of the woods ;).

I received an MK3-USB and updated the firmware to version 481. This helpt a little bit. I then changed the AC1 Limit from the default 50 A to 15 A. 2 Parallel, making it 30 A. This made a big difference. Charging is okay now and no strange noises. I am more than a kilometer away from the grid inverter and almost the last house that's connected to the grid.

Next step, installing the ESS Assistant. Here it stil goes wrong. The Multiplusses are struggling to control to stay on the grid and work the inverter at the same time. It's better than before, still I have the feeling something it throttling and strucling. Overload still appears, it now only takes a longer time.

I find the ESS manual confusing and there are mistakes in it. Certain items do not appear in my screens. It fails to explain the values and the consequences of certain settings. My question is: who has an good example of the ESS Settings?

  • Fronius with zero feed-in.
  • Use battery power until 20% soc
  • Stay connected to the main but start loading when SOC lower than 20%.

Robert

ddickov avatar image
ddickov answered ·

Hi Robert if you are able to I would try a power down and the. Re boot them both and see how you get on.

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ddickov avatar image
ddickov answered ·

If you have a Bluetooth ve direct adapter, Could use the iPhone app or android to view the current firmware version, just save your settings also before you do it, if you are using the laptop or pc a MK3 to usb would be required, this can be paired with victron connect for windows and that would update the units to the same firmware as they both have to be the same to operate correctly, if you could screen shot your settings and post them in the reply thanks

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robertg66 answered ·

Hi David, Tanks for your reply. What would be the best way for you to check the settings? Both are running on firmware 2623475.


Robert

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ddickov avatar image
ddickov answered ·

Hi Robert would need to see your multiplus settings to confirm it is set to transfer the grid through to ac1 out, this maybe disabled in the system settings, have you checked both multiplus’s are running the latest firmware also. If all checks out I would maybe suggest sending it to victron to inspect it thanks david

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