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graham-willsher avatar image
graham-willsher asked

How to get data from each victron inverter in a parallel installation

Hi,

I have a setup where I have 2 Multiplus II (one is a GX) inverters connected in parallel to a bank of 8 x US5000 Pylontech batteries.

I get data back from the GX via Node Red and this gives me an overview of the setup, so not problem there, and I am able to cvontrol the system as a whole.

Is there anyway that I can get data from each seperate inverter not a system overview (in Node Red), as I am trying to find out why the system is not balanced as one inverter runs the fan hard under load whereas the other does not. The cable length from each inverter to my battery bank is the same, so this should not be a problem.

I am sure that the individual inverter data is available if you physically connect to each inverter, but I would like to get this data remotely, as I don't have the necessary cable or a laptop.

I have also read that the latest version inverter should be the Master in the setup and I will investigate this option as well.

When the system is running a scheduled charge in the early hours of the morning the fan sounds like a jet engine (I have already checked on the serial numbers for the retrofit fan kit and although I did not need one I have installed it and it did not make a difference).

Any help/advice would be greatly appreciated.

Thanks,

Graham.

VRMmultiple inverters
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7 Answers
nickdb avatar image
nickdb answered ·

Nope. A parallel set is logically one inverter and reports as such.

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ardje avatar image
ardje answered ·

The master MP2 creates the PWM for the slave MP2. The slave is just an extension of the DC to AC circuitry.
There will be discrepancies in internal resistance between the MP2's. In order to cope with this inbalance the following must be true: the AC-OUT as wel as the AC-IN should not be connected with the thickest cable ever seen from distribution point. Compared to the MP2 internal resistance these wires must have a "significant" resistance compared to the MP2, and this significant resistance must be the same as much as possible (the cables must be equal length up to the join bar). So on the AC side from the distribution point to the MP2 needs to be a "thin" cable in order to have enough resistance.

These are just the default suggestions. I don't know what exactly is considered the right thickness..

Because your jet starts when you are trying to do topup in the morning I assume the inbalance is on AC-IN and the battery...

I did not really answer your question though. So excuse me for that.
Also having a GX inside the same box might add enough to the heat to go superturbo. I assume the GX part adds about 5..10W. The SoC itself is very energy friendly, but it also needs to feed drivers etc. .

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ardje avatar image ardje commented ·

Edit: as @nickdb said: use clamp meters.

Original comment:

Thinking about that: you can test this easily:

1) Swap the +DC of your inverters to test.
Never swap the -DC, or first disconnect the VE.Bus cable.
2) Swap the AC-IN L of your inverters to test.
3) Swap the AC-OUT L of your inverters.
If the noise moves to the other inverter then you know which part is unbalanced or dimensioned wrong (too thick on the AC side, or not equal path on the DC-side).
I would actually start on 2) and 3) because 1) is very obvious and noted in almost every video so you there is little chance that is wrong, but 2 and 3 sound counter-intuitive.


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nickdb avatar image
nickdb answered ·

This is what clampmeters are for, vital for parallel setups. Any imbalance will be shown.

Mucking around with swapping feeds etc isn't just time consuming, it is a good way to break something expensive.

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Fideri avatar image
Fideri answered ·

@graham Willsher

I haven't looked so I don't know for sure but I read somewhere that under device list, you see the parameters of one inverter? If that is the case, you can derive the parameters of the the other inverter by subtracting these from those shown on the main VRM page.

F.

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graham-willsher avatar image graham-willsher commented ·
Hi @Fideri ,

Thanks for your reply.

I have looked under the device list and found the inverters under the 'VE.Bus System' heading. Unfortunately it does not shed any further light as to how I can individually address each inverter.

I shall continue looking.

Regards,

Graham.

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nickdb avatar image nickdb ♦♦ commented ·
This is incorrect.

You can see the different serial numbers of each and their device ID for troubleshooting, but as I have already stated.

It is ONE logical inverter. There is NO tracking of independent data for each.

You can only use a meter for this, ideally two if you want to check concurrently.

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Fideri avatar image Fideri nickdb ♦♦ commented ·

@nickdb

Can I see their respective AC output if I fit a meter on each of them?

F.

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nickdb avatar image nickdb ♦♦ Fideri commented ·
If you mean an energy meter, via widgets, yes. Not via the dash. That seems a really silly and expensive alternative instead of just buying a clampmeter, which anyone attempting this, should have. There is only a need to see this for post installation testing, or in the event of a fault. In both those instances an onsite visit and clamp is the best course of action. In normal ops, there is zero need to see individual stats, beyond personal curiosity.
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Fideri avatar image Fideri nickdb ♦♦ commented ·

@nickdb

To clarify, if I had a problem such as @graham Willsher , I would take a different approach. I have a multimeter at hand in case of any problem.

I don't have any problem at the moment. But I'm very much interested in the data for other reasons. Buying energy meters is expensive but I can't think of a cheaper way of getting the data from VRM.

F.

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nickdb avatar image
nickdb answered ·

Re Fans. Don't fit the retrokit to an already modified system.

At full taps, they will be loud, mine are the same at full charge.

The modifications only reduced noise at lower Fan RPM, it made zero difference to the full speed noise.

Also.

Recently, some new systems would make a lot more noise again at lower RPM. I experienced this after replacing one of the pair and immediately assumed the system was unbalanced.

My meter showed it wasn't, so I just lived with it, until 5.08 firmware was released with an improvement for this behaviour.

They are now more uniform again, but one is a bit louder.

With changing hardware revisions that is bound to occur.

And definitely make the newest one master, if there is a big difference in manufacture date, that will never help either, more so if one has "lived" more than the other.


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graham-willsher avatar image
graham-willsher answered ·

Thanks all for your replies.

I will be speaking with my installer re the best way to move forward with this. Having the never inveter to be the Master will be one thing to do and using clampmeters to figure out (and hopefully fix) any imbalance on the inverters.

The last resort (if all else fails) would be to replace the 2 inverters and just install a single large multiplus II 48/10000 which would be the capacity of my exiting 2 parallel multiplus's. I would also need to purchase a seperate GX device so that I can program it as currently. Not the ideal solution, but if I can't get this resolved it might have to be an option.

Thanks,

Graham.

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Fideri avatar image Fideri commented ·
Getting a 10k multi is the simple option, complicated when you already have two 5ks.

However, instead of merely a GX, you need an MK3 to program the multi. The GX is for going online and coordinating the charging.

Good luck.

F.

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graham-willsher avatar image
graham-willsher answered ·

In answer to my own original question re getting data from the individual inverters, @nickdb helped me out with this by sharing a MQTT nodered flow with me, where all of the data held in the inverters is available.

With a little investigation (getting the correct settings for my system) I was able to get all the necessary data from the inverters, and can now see that my system is not balanced.

So now onto the balancing of the system. :)

Graham.

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