2 x Quattro 8000 in Parralle, with incorrect AC amps out reading but watts correct

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Paul B asked Jul 11, '22

2 x Quattro 8000 in Parralle, with incorrect AC amps out reading but watts correct

Has anyone got any suggestions here as to how to fix this or what to try, We have had this reported to victron service now for over 4 weeks, with no resolution.

The below pictures are showing a screen on the customers Cerbo (fw 2.87) - we have also tried without the multi control being connected. Please NOTE the The AC out amps reading as its incorrect by a large amount however the WATTS reading is correct.

This display error also shows the same figure on the tiles.

Of note is that if we turn the two units off for 30 min then power back on the error is resolved sometimes for 1 to 2 days then the issue reappears. and it does not mater if AC1 in or AC2 in is used as the power source

We have replaced BOTH cerbos with two more brand new units same issue. Also even if the Cerbos are disconnected and only the Multi control is connected the amps limit is always out by the variance in the output ac1 amps reading.

The above show the AC amps being incorrectly displayed HOWEVER the watts reading is correct.

2 x brand new Quattro 24volkt 8000 units using 497 firmware also the VE.BMS selection has been selected. both connected in Parallel.

Of note this boat has 2 full sets of these quattros (4 in total) AND BOTH SETS SHOW THE SAME PROBLEM

Please see the attached pictures - this error only occurs if the units are in Parallel in stand alone mode they work fine, and sometimes it only shows up after a few hrs of usage and the in balance varies

The amps reading error then causes the AC amps limit to be incorrect by the amount of the reading error.

If you turn off the incoming ac source then the outgoing amps reads correctly, see picture below

OTHER Pictures Below

MultiPlus Quattro Inverter Charger

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Andrew Ayles commented · Jul 11, 2022 at 01:29 PM

If you look at this screen shoot of two 5kva multi's in parallel you will see the same problem and like yours it's on the ac in and ac out. It only occurs when the generator is connected. When inverting the maths of amps, volts and watts works out perfectly. The problem only occurs when ac in is connected. If you set a generator current limit of 40Amps the generator actually limits to about 20Amps with a tong meter. If you reprogrammed the Master as the slave and the slave as the master the reverse situation occurs where If you set the generator current limit to 20 amps it actually limits to about 40 amps when tested with a tong meter. All the time regardless of which is master and which is slave the watts seem to be reading roughly correctly. It is the current that is incorrect but only with the generator connected. All reads perfectly when inverting. This problem has been ongoing for me for nearly two years now. Swapping the master and slave got me out of trouble because at least now I could set a generator current limit of 40Amps in the remote console and have a real life limit on the current tong meter of 20A and not overload the genset. Love to know what the problem is as well.

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Paul B Andrew Ayles commented · Jul 12, 2022 at 12:30 AM

Hi Andrew, yes I also have another customer with 2 x multiplus 24/5000s in Parrelle also giving the same issue, this goes back 1 year but victron does not seem to recognize the issue, and does not seem to be interested in getting to the bottom of the problem, the screen pictures say it all but and for use it happens on shore power. and generator,

We also tried swaping the master and slave and thought we had solved it but over time it the issue returns. we have also noticed that if you turn the units off for 30 min or more then turn them back on the problem goes away for upto 3 days then reappears, This we have noticed on the 2 x 8000 units,the customer with the 2 x 5000 units has given up chasing the issue hoping that a latter F/W update will fix it, but that does not solve it.

If you have any other quirks that come along that maybe related please post the reply, as we seem to be able to duplicate it but Victron cant, (or they are not looking)

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Paul B Andrew Ayles commented · Jul 15, 2022 at 08:28 AM

Andrew some things to look for.

When your generator is running using a clamp meter check the amps output on AC1 out from the master and the slave, both have the same amp out put reading, if not the same then this may indicate that the two generator ac in cables to the multi are not the same lengths.

whatever the Masters output reading is then its doubled and thats were the amps reading is coming from.

we still have not solved our issues yet but we have identified a imbalance in the ac in amps on the master and slave and the equal length cable split to each inverter charger. something for you to look for. also AC1 out

will advise more when we have finalised the situation.

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Paul B commented · Jul 12, 2022 at 12:56 AM

In nov 2021 I reported a similar issue and the post has been closed with a notation that the fix was added to 2.80~24 fw, this is GX device firmware and not multiplus or quattro fw so I dont know how this can fix it. the issue even occurs with no gx device in the system at all as well. ie by just using a multi control. you can see the boats own amp meters and the ac current limit is way off.

however I do not think that this has been completely fixed or its been reintroduced somehow.

https://community.victronenergy.com/questions/107870/2-x-multiplus-5000-in-parralle.html

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Modifications Space

Node Red Space

Answer 1 · 2023-03-26T15:19:43Z

Someone in another thread suggested this is a Power Factor issue with AC, and it does not occur when inverting because it does not apply to DC: I don't pretend to know about PF and the intricacies of sine waves...but I don't think this is a PF issue.

Reference: Why are shore power input amps/watts wildly disagreeing? - Victron Community (victronenergy.com)

Sorry to resurrect an older thread...but I've been TEARING my hair out trying to solve this same issue:

AC-IN  L1                    210v     33.0A
                            4169w     50.1hz

AC-OUT  L1                  210v      36.5A
                           4890w      50.1hz

The keen observer would point out that I'm currently in assist mode, and you'd be correct. The math in this simply DOES NOT WORK.

ACIN  = 210v * 33.0A = 6930w (Showing 4169w)
ACOUT = 210v * 36.5A = 7665w (Showing 4890w)

I'm relatively certain based on what I know I'm pulling from shore power, and my usage, that the WATTS are the correct figure. I've tested it independently with a clamp, but it's been a while.

The real issue comes in because very few settings in the system are based on WATTS.

Input Current Limit:   41A

Strictly factually I'm connected to a 32amp 50hz shore power inlet at the dock. But because of the disparity in watts vs amps, I have to "massage" the shore power amps.

This has another gotcha. The calculation doesn't stay the same. Sometimes it's closer to 1.5, sometimes almost 2, sometimes it's almost correct at 1 to1.

System:

Quattro 12/5000 220 x 2 in Parallel configuration. If I remove the parallel config and shut one quattro off (but leave all the wiring the same) - the WATTS and AMPS calculation is correct. Then I can switch to the other one in single mode, and they are correct...then I can put it back in parallel and they are wrong again.

Anyone have ANY idea how to help me track this down? I'm quite technical and understand my system really well, but I've been fighting this for over 6 months.

Thanks ahead of time. I still wouldn't trade my Victron stuff for anything else out there!

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