question

Enrico Zanolin avatar image

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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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?

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?

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.

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.

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



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

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

Interested in the AC input graph.

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.

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.

reed avatar image reed Enrico Zanolin ·

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

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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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

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.


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

Hi Guy

Will do, once i have being across to the client place later on the week to up date his firmware and reset his settings etc.

Regards

Rob D

NZ

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

Guy, I noted Firmware version 481 (9th Feb 21, False overloads proved still to be possible. A cause for this has been found and a solution is implemented to prevent this.) is now available re the changelogs and Victron Connect updates.

Has this solved this problem? Would be good to finalise the tread with a solution.

Cheers

Indeed it would, but it would be very presumptive to say that the solution is now final without more time in the real world.

The good news is that with each improvement, the number of issues is reduced, and allows focus on those that remain. Things are continuously improving, and we now hope resolved for most that were experiencing this, if not all.

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

Hi Guy

I will be doing the second update for the same client next week 22/2/2021 for a on going issue with over load warning shuts downs etc. They are running ver 478 and it did once so far, i have set the inverters to LOM disabled as a test, so far OK, but needs to be turned back and run the new ver481 to see if that solves the issue or not. So will install ver 481 and will update this site on the prgress to see how this ver 481 behaves or not.

Regards
Rob D

NZ

Hu Guy

I have updated all the inverters with the overload LOM issues with Ver 481, today 23/02/2021, and will run on test now to see how it runs now, and will keep this site posted on the result in the comming weeks etc.

Regards

Rob D

NZ

Hi Guy

Yesterday I have updated the Multiplus II at our customer for the newest firmware 481.

My customer and me were really disappointed because of the sporadic overload shutdowns.


Here is my observation :

our system is : 3 x Multiplus II 48/5000, Froinus Symo 12.5, Smartsolar MPPT 250/100 and BYD LVL 15.4

The Fronius is connected in the AC-Out. There is only 9kW PV on the Fronius. There is Grid

We run ESS with batterylife

The overloads happen almost always when grid is available and ESS is running (meaning, loads supplied by either batteries or battery + Fronius) .

The overloads never happened during grid loss (inverting mode) or during passthru

We also observe the overload shutdowns most of the time happen on sunny days, especially when Fronius produces high power .

Also we observe these overloads have to do with the load as well, for the two of the shutdowns happened, the customer was using the ironing . So on the load side of the inverter was 2500Watts , which was fully supplied by the Fronius.


We are really hoping that this 481 solves the overload problem. Because the customer feels really uncomfortable, as it is not clear when this overload might happen and we are loosing so much time travelling back and forth to the installation.

Hi

Yes i had a simlar issue so have installed and running the new Ver 481 firmware to date it is OK. But it is totaly random error. It is all to do with the grid impeadance on long power lines etc Check your your line impeadance? As power is pushed and pulled the inverter thinks this a overload when it is not. To prove this you can disable the LOM setting under grid settings and run that to see how it runs, If all ok , might have to run a external grid protection device to over come the ovreload errors and leav LOM disabled, until Victron find a real fix to the issue, So far Ver 481 is Ok to date lets keep finger crossed.

Regards

Rob D

NZ

Hi Rob, thanks for the feedback.


Indeed the power line is quite long. The distance to the gridpoint is 100m. However we use 25mm2 cable for carrying the 15kVA grid to the system, we think this cross-section should be ok. Do you think increasing it will decrease the impedance ?

LOM was disabled all the time. But overload shutdowns still happened.


Let's hope this new firmware solves all problems.



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

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.

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

@Guy Stewart (Victron Community Manager) have loaded it here to test. Annoying that assistants have to be reloaded after an update. Apart from that, so far so good.

I had also been experience spurious overload warnings so keen to see if it makes a difference.

Thanks, yes, the current laboured procedure required to do a firmware update on the VE.Bus products is getting some improvements, hopefully this year.

I put it off myself a few weeks for the same reason :)

I have not experienced an overload since updating to this firmware, but they were rare and unpredictable (usually coinciding with strange grid events during storms) - so hard to reliably reproduce for testing.

Hopefully those in more marginal conditions where they were more frequent can quickly report improvements for a wider roll out.

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

Will we ever see remote FW updates of VE.Bus products over the air?

Its a sadly missing feature

Hi @Alan,

I’ve asked Matthijs a few times over the years. There are SO MANY improvements in the works for the VictronConnect and Victron ecosystem that particular feature is unlikely.

At least in a way that is supported - I don’t suppose you have read this though? Note the very large and clear disclaimer at the top, and no further discussion of it outside the modifications space please ;)

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

Yes I’ve read this method and have yet to try it. The huge disclaimer put me off.

Hi

I have loaded on the new Ver 478 into a Mulitplus2 one site that had random trips 21/1/2021, under testing now.

I do have one other site that might have similar issues which was installed at the same time. I will follow with the client to see how it is going etc.

Regards

Rob D

NZ

Hi All


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

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.


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

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".

@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.

alan avatar image alan michael2019 ·

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

It's made no difference to my random overloads.

Hi Nick

Same issue here with Mulitplus2 5kw in parallel Ver 478 not cured the overloads.


Had to disable warnings to stop getting emailed. Been like this since it was installed.

screenshot-2021-01-27-at-092234.png

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

warwick avatar image
warwick 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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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


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

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

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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Did you update both inverters to 478?

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