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Enrico Zanolin avatar image
Enrico Zanolin asked

MultiPlus II overload on grid failure

I have a MuliPlus II 5kVA 48V which I installed to mitigate regular load shedding. The system has been idle for about 6 months after which it has had a trial by fire of about 20 events in the course of 2 weeks. It handled everything great except for on 2 occasions where the MultiPlus tripped and reported an overload as the grid failed. In both cases the load was minimal at the time of the trip +- 200W. In both cases I reset the system and reconnected the exact same load and the system came up fine.

Can anyone explain how this can happen? Is it possible for the grid itself to cause something that is reported as overload condition?

A portion of the cable run that feeds the Multiplus power from the grid shares a conduit with the cables that return power to the house. Could this be an issue (ie an induced eddy current)?

Thank you.

Multiplus-II
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h-m-heating avatar image h-m-heating commented ·

We have been having problems in two different locations where installations of MultiPlus-II 48/5000/70 both are Grid connected, the Inverter shuts down with a overload fault light fixed on and Low battery light fixed on, the battery is not low and we only have a very small load on the system, which suggest from the LED Definitions that we have "High DC Ripple Alarm" we can reset the fault by switching off the Inverter and switching on again, both installations have BYD battery banks.

We tried increasing the Grid Voltage that the Inverter disconnects from the Grid as suggested by someone before, the Grid Voltage does drop extremely low at times which is why we installed this type of system so that it takes over the supply to the property.

I have read information on another site where an installer added Capacitors to a system using a MultiPlus-II because they were having this type of problem with another type of battery, the idea was to smooth out the DC side, explaining this doesn’t normally occur in the older MultiPlus because it has more Capacitors in it’s design which can deal with this problem of “High DC Ripple”

I wonder if Victron Energy have any comments on this problem?

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marekp avatar image marekp h-m-heating commented ·

I had similar problem.

Asked the question here:

https://community.victronenergy.com/questions/68531/l3-overload-with-practically-no-load.html

Did not get the answer.

Oh no, I got the "answer".

I'm sorry but I don't see the issue...a -warning- is not a problem, an -alarm- is.

I wonder how far after warning is an alarm?

A day, two days or maybe more than 5 years?

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h-m-heating avatar image h-m-heating marekp commented ·

Hi

Perhaps I did not make clear in my problem.

The problem is that the Inverter shuts down completely and I have to travel to reset it as there is no one at the site, this happens frequently.

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marekp avatar image marekp h-m-heating commented ·

I understand that you are at the ALARM stage and your system turns off.

I am at the WARNING stage and would like to know how to avoid getting to ALARM stage at which you are now.

I would not like to wait more than 5 years to find out that I have no more warranty.

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gerard-goeders avatar image gerard-goeders commented ·

Hi. We have a similar problem than yours. For any Reason the inverter overload and switch off. We don't see any Big load, no problem of over or under frequency or voltage. I limited the charge and discharge to few amps, nothing changed

I ve tried to disable the LOM without success, tried to change setting of frequency without success.

It happens After few minutes when it charge or discharge, i ve been there to try to generate the failure by myself and impossible to create it... It Always happens randomly. The one moment we Can see clearly that failure, IS When we discharge the battery to 20% and force the charge during the night, it happens around 30%... Inverter overload and switch off. The customer switch off and off manuely and works again After (sometimes it triggers off several Times). Can the problem Can Come from the battery. It's a BYD LVL stackable, ESS mode,MP2 5 kva... The system IS connected to a 3*230 volts triangle grid, but we did it on another place and it works well...

We already changed the Unit once.

Our customer is at 2 hours from our office, i Can 't go there each test to test and test again.

Our customer IS really upset now and we have until end of january 2021 to solve the problem... Or at least understand where it's coming from.

Otherwise we dismount the system and it's not a good advertising for us and Victron

I have quite a long and good experience with Victron with a little bit more hundred installations.

Any Idea or support ? If it's coming from the grid (it's in the middle of a small City, not far from everything) ?

I would be surprised. But possible too... How to check that? I Can ask the grid operator, but not very easy to make them move in Belgium



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Paul B avatar image Paul B gerard-goeders commented ·

A few things I have found that maybe of help, some of these are work arounds but may help you diagnose the issue by isolating different items,

I have to deal with a pack battery with internal BMS and internal FET CUTOFF, thats been supplied from China by the customer.

now if a cell fault occurs the batteries turn off and the inverter trips off with overload and low batt. and also with high pack current.

Plus the wires inside the 10Kw pack were WAY UNDERSIZED as well

I also found that if grid tie on AC1 out is involved then the batteries are full that one pack was cutting off at 54.4 volts which was low anyway also as the frequency shift was not moving fast enough, the batteries would turn off but the high voltage spike was not showing on the VRM then as there was basically no battery the inverter turned off as protection thus shutting down the grid tie . and then I would see a OFF status in the bus info on the VRM, To solve the Frquency shift issue , I then installed a contractor that turned off the 3 grid tie units if the voltage went over 54.2 volts by using a assistant to open K1 when the voltage went over 54/2 for 1 sec then another assistant to turn it off when voltage went below 54. worked well and solved a lot of minor issues

The system was 3 phase and badly phase balanced , however the site had NO 3 phase items all were 220v, so I then modified the site to single phase mainly to remove the phase balancing issue. and this has worked GREAT. However I then had a a new inrush issue with the batteries dropping out at startup or reset because of hi inrush

The banks is 20Kw (not supplied bu us) in size with 3 x 5Kw Multis in parallel (supplied by us).

ANYWAY end result. I opened the battery banks and directly connected the Neg to the battery output terminal THUS removing the BMS's auto BMS controlled battery cuttoffs, this SOLVED all my issues.

the BMS is still in there balancing the cells, but there currently is no cuttoff if one cells goes hi or low, have set the inverters low voltage quite hi,

Ill be replacing the BMS in due course with one that we can control with the Victron 2 signal BMS system.

I am not a very big fan of thye batteries that have inbuilt BMS cutoffs especially now

Well the above maybe of help or not but its a overview of the issues I have had around this similar issue

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8 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Enrico Zanolin

The only thing I can think of is if the system disconnects the grid too late, under 'brown out' conditions, the system follows grid voltage, when it follows this to a too low voltage it has to raise the voltage again after disconnecting, some loads can make this hard to do.

You could tweak the settings to disconnect AC input at a higher voltage to see if this helps.

also: what LOM detection do you use (if any)

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Warwick Bruce Chapman avatar image Warwick Bruce Chapman commented ·

What are the chances you have graphs from VRM that show the moment before the trip happened?

Interested in the AC input graph.

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Enrico Zanolin avatar image Enrico Zanolin Warwick Bruce Chapman commented ·

I did examine the graphs myself and there where no anomalies. The graph looks as one would expect. If you think about it there is no way that the VenusGX has the resolution to be able to pick up any kind of spike.

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screenshot-2020-01-13-at-142641.png (136.7 KiB)
Enrico Zanolin avatar image Enrico Zanolin commented ·

Sorry for my delayed response but I had to wait for my friend to come back from holiday so I could get my MK2 programmer back from him.

My country grid detection (LOM) is set to none as I do not backfeed to the grid as this is currently not supported by my utility.

Accept wide input frequency was checked and I have now unchecked it.

AC low disconnect : 180
AC low connect : 187
AC high connect : 265
AC high disconnect : 275

I have upped the value for low disconnect to 195 and low connect to 202.

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reed avatar image reed Enrico Zanolin commented ·

Hi. Solved a similar problem. If you have No grid code set please set you Ac low disconnect to 195vac of even 200ac....low reconnect from 202ac and above. Where i am in Zimbabwe my grid is above 240ac sometimes on failure it browns out as low as 170ac! Unless you install some external capacitors the Mp2 struggles to get into inverter mode from such a low voltage to raise it to 230! HENCE DC RIPPLE SHUTDOWNS..LOW BATTERY LIGHTS.and BMS SAFETY SWITCH OFF..etc.

Good luck.....also remember to upgrade to firmware 478

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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

This is an old question, but with some recent activity, a new VE.Bus firmware version 481 - includes fixes for spurious overloads.

Fixes include:

  • Prevents permanent lock on ripple error due to overload.
  • Improvement of acceptance of grid in “floating phase” systems icw generators.
  • Solved: Spurious switch off due to overload.

Available on VicProf and the firmware dropbox now for manual update; and will be included in VictronConnect a while from now.

Any and all strange issues related to overload should FIRST AND FOREMOST update to this firmware version, and then please report back if they are still occurring, or now fixed.

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Rob Duthie avatar image Rob Duthie commented ·

Hi Guy

Thanks for the update, i have 4x 5kw 48v Muliplus2 2x in parallel modes on two sites with spurious overloads at random times they had the last update 477 before xmas time, I only just found this thread just now which might solve my problems? thinking it was my AC cable lengths etc, which are all the same lengths etc I did current checks for each inverter in parallel and all within 100 to 500 mA of each other at half load tests. So this update might solve the problem? Because when as watching the over current occurred when the load was only around 3kw for both inverters and some times less than that. when i checked on the VRM logging for the over loads it was correct.

Because the only way to do a update is to travel to the clients place be there with a laptop and update etc? This takes time and travel costs who pays?

I am Vicprof site member etc. There needs to be some bulletins sent out to installers to advise of such important updates tied to the serial numbers of units installed, tracking? just a thought might save some stress for installers with odd issues etc. my 2 cents worth.

Regards

Rob D

NZ

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ Rob Duthie commented ·

Hi @Rob Duthie,

It is worth trying this update for those sites, it would be good to hear your feedback if it resolves the issue or not either way.

This is a relatively rare issue, and most installed MultiPlus and Quattros are not experiencing any issues and do not need to do the update.

This is not an issue that is specific to a range of serial numbers, but improvements to the handling of site specific conditions. Only those systems with unusual overloads (that are nearly always due to a strange deformation on the AC input supply).

Regarding being paid for your time installing Victron - that is a conversation between you and your Victron supplier, Victron Sales manager and your customers. The guidelines for this community are intended to keep discussion here focused on the technical side of Victron, not the business side.


This current firmware update, while available now, has not yet been announced, except on this community. Once it is ready for a general announcement it will be via the Victron Professional email newsletter - past editions of the newsletter can be seen here - https://professional.victronenergy.com/news/

If you don't already receive the newsletter in your email already, where this will be announced when it is ready for widespread promoted release, then please get in touch with your Victron supplier or Victron sales manger and ask to be added to the list.


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nickdb avatar image nickdb ♦♦ commented ·

@Guy Stewart (Victron Community Manager) victron connect only has 4.77 firmware. When will an update with 4.78 be available?

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ nickdb ♦♦ commented ·

No release date is set yet, I haven't heard any issues arise yet, but I would like some more real world testers.

Remember it is still possible to use VictronConnect to do the firmware update, you just need to fetch the update file manually and then select it inside the VictronConnect firmware update menu. It just isn't bundled with the app yet.

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Rob Duthie avatar image Rob Duthie nickdb ♦♦ commented ·

Hi Nick

It available now on the Victron Pro site. i have installed it on two site today which had no issues, but i have two 10kw sites that need to be done as they have the odd Spurious switch off due to overload for no reason, when the inverters are only at half power.

Regards
Rob D

NZ

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reed avatar image reed commented ·

I have just loaded the 478 firmware on the MP2. I am in Zimbabwe and have been experiencing these random overload encounters!

In testing so far...everything seems to be fine. Inverter carried on nicely when the grid failed! More testing needed for sure.


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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ reed commented ·

Nice, thank you and look forward to hearing from you again either way.

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Warwick Bruce Chapman avatar image Warwick Bruce Chapman commented ·

We have 478 running on 20+ sites for a month now (a few even since it was in beta) and it definitely resolves the "phantom overload".

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michael2019 avatar image michael2019 commented ·

@Guy Stewart. I just updated the firmware of my Victron 10000VA connected to 1500AH Gel Batteries to 2653478. But it seems not to stop this spurious overload fault upon AC in failure. This is really frustrating and making us to loose trust from our customers. Note it does not happen all the time upon Ac in failure.

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alan avatar image alan michael2019 commented ·

Have you checked the Hardware revision? Could be something like this

https://powerforum.co.za/topic/4347-victron-behaviour/page/2/#comment-63697


Edit, never mind just noticed you are running a 10kva quattro

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nickdb avatar image nickdb ♦♦ michael2019 commented ·

It's made no difference to my random overloads.

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Rob Duthie avatar image Rob Duthie commented ·

Hi Guy

Re spurious shut downs i have installed the Ver478 and it still does it randomly at low loads of 1 to 2.5kw

I can send you the client link for the VRM data to have a look at if required ? my email raduthie@gmail.com


This is a 2x parallel 5kw 48v mulitplus installed in Dec2020 with a 5kw Fronius on the AC output\, setup as a micro grid. with 21 Kw Pylon tech battery pack. CCGX device, All leads are equal lengths for AC and DC battery, as per requirements, Energy meters fitted as well etc, as i have done some other installation of similar type with parallel systems, and they seem to be OK to date. Has equal AC current on loads of around 2kw 9Amps and can vary by about 0.2-0.5amp per inverter.

This is urgent matter as this is happening to much now, i have contacted the supplier dealer in NZ just waiting to hear back still.

Attached VE config txt file

Phil Pignieri Solar.TXT


Regards

Rob D

NZ

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pig-pignieri-solar.txt (3.1 KiB)
Warwick Bruce Chapman avatar image
Warwick Bruce Chapman answered ·

I have a MultiPlus 3kVA which handled same “demand side management” blitz you mentioned. It supports much larger loads and has never tripped on grid fail in the year it has been installed.

This sounds very unusual. I’m interested to know what’s causing it. Do you have anything else connected? Solar, GX? Also, what batteries?

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Enrico Zanolin avatar image Enrico Zanolin commented ·

System Specs

  • Multiplus 48/5000/70-100 240V
  • Venus GX
  • 4 X 180Ah AGM Batteries
  • RCD protection on input and output rated at 63A
  • 40A breaker on MultiPlus input
  • 20A breaker on MultiPlus output.
  • 70 sqmm 2 meter battery cables
  • 10 sqmm AC input cable
  • 6 sqmm AC output cable

I have limited the input current on the MultiPlus to 17A. Perhaps this could be an issue, but I don't see how, given that the trip happens on grid failure, so technically the input current should be 0A.

None of the RCD's or breakers tripped


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selwyn avatar image
selwyn answered ·

I have two separate sites that have gone into an overload condition on a Multiplus II 5kVA 48V. Switching off/on the Multiplus has fixed both sites, but it is inconvenient when this happens as all backup circuits are left with no power.

Neither site had an AC-in failure reported on the VRM site. The only anomaly on the one site is the output frequency dropping to 48.83Hz while the input frequency remained at 50.01Hz. The charge status remained at Absorption. For the other site there were no anomalies. There could have been short grid failures that were not long enough to be recorded on the VRM site.

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bulraydin avatar image
bulraydin answered ·

Dear @Guy Stewart (Victron Community Manager) we have the same sporadic overloads happening on one of our sites, I have been trying to write about it in a separate discussion. However this thread is really what I am looking for. I will update the firmware asap and see if it gets better.


However besides the sporadic overloads and shutdowns, which I could never catch we have simultanously also AC2 out dropouts. I don't know yet if overload warning is related to the AC2 dropouts. However I really don't understand why the multiplus go to 'inverting' state when grid is available ? This happens only under ESS conditions. Is this problem related to the same 'sporadic overload ' problem ?

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·

Perhaps, and updating to 478 would certainly be the first thing I would now do to see if it improves.

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reed avatar image reed commented ·

I loaded the software about 48 hours ago, so far so good! please go ahead and load the firmware.

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h-m-heating avatar image
h-m-heating answered ·

I have added the latest 478 Firmware update three days ago and so far all has been OK, I need a week or two to make sure it is continues to be OK.


I have noticed that even before the Firmware update and this is still happening, the the Low Battery Light is on even with the the Battery fully charged and only a low load on the system.


Any ideas why that might be? We have a Multiplus-II 5000, BYD Lithium Batteries, running ESS and the total system has only be in since late last year.

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Rob Duthie avatar image
Rob Duthie answered ·

My first software update did not fix the issue still has spurious shut down when load was around 1-2.5kw across the two 5kw muliplus2 inverters in parallel setup.

Regards

Rob D

NZ

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Warwick Bruce Chapman avatar image Warwick Bruce Chapman commented ·

Did you update both inverters to 478?

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Rob Duthie avatar image Rob Duthie Warwick Bruce Chapman commented ·

Yes i did and have done 3x parallel system to date. and it again failed to day client had reset both inverters again. Load was only about 2kw watts at the time, totally random when this happens even on lower loads.

Regards

Rob D

NZ

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bulraydin avatar image
bulraydin answered ·

Dear @Guy Stewart (Victron Community Manager)

it has been now almost 2 months , since we have updated the firmware to 481. It is comforting that the overload shut-downs don't happen anymore.


However the AC2 output seems to go and come back now and then, although the grid is quite stable.


We cannot understand why this keeps happening , were hoping that the 481 solves it as you have suggested.


Any ideas what to do ?


Best Regards


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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·

Also really happy to hear the overloads have resolved with 481.

Please create a new question for the new issue though.

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