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Pylontech stacks in parallel installed with LV-Hub incorrectly reporting charge / discharge current & limit

System - Single phase - 2x 5kw Multis in parallel.
2x stacks of 5 Pylon US2000 in parallel with LV-Hub
Cerbo GX
It would appear that the LV-Hub doesnt correctly report the correct available charge / discharge current to the GX.

The GX is showing 125A. (which follows the 5x25A mentioned in this doc:

It should report 250A ?

The LV-Hub, also does not correctly report the operating charge / discharge current the the batteries into the system. (Noticed this as we also have a BMV in the system)



Chris asked
Chris answered ·

4 Answers

Any known issues with firmware 430 on a Multiplus 5kW ?

Two 5kw Multis operating in parrallel - single phase system.

Bench configured and all was well. However, while loading the system up in anger on site, some strange things happen. Master goes into overload and the slave bugs out.

It was looking like they were working together as you woudl expect - i.e. mirroring each other.


When generator is operating - the Multis seem to load it up to around 300w then they trip again on overload.

Cabling is as near as damnit same lengths.

Chris asked
wkirby commented ·

2 Answers

Flicker and wild voltage and frequency variation of Quattro output when operating with generator


We are experiencing this same issue on multiple sites. Both with AC connected PV and sites with charge controllers.

Quattro 5kw off grid system. 50hz 230v

When the backup generator is operating, the output from the Quattro varies wildly and also it appears so does the load placed on the generator - to charge the batteries (from the VRM portal data)

This is backed up up by the display on the generator (Hyundai DHY6000) which shows frequency.

Frequency output from the quattro is so unstable it cases the Fronius PV inverter to cut out and also the washine machine on site to go into fault. Also voltage is all over the place, and all this causes lighting flicker too.

UPS function setting is off

I have tried lowering the shore power setting.

I have tried lowering the output voltage slightly on the Quattro. (output on the genny when unloaded is 230v)

Dynamic current limiter on or off makes no difference.

Accept wide frequency range is on.

I am assuming that the quattros inverter attempts to track the AC input frequency and doesnt do a great job of it.

If powerassist was disabled - would this prevent the inverter output from trying to track whats happening with the AC input ?

Any ideas?



Chris asked
Chris edited ·

3 Answers

60kW Off Grid system with Quattro and Fronius +85 kW Storage

Hi Everyone,

I'm currently planning to build a off-grid solar system to be used in an agriculture farm. The system will be mostly used to power the water irrigation system and to will have to provide a mini-grid as we are several Kms away from the grid.

The system will be composed of the following components:

1-60kW Solar array with 450W mono panels

2-3x Fronius Eco 27 3 Phase Inverters

3-4x Quatro 15000VA (2xPh1, 1xPh2, 1xPh3)

4-85kW Battery Storage


The main load of the system are the water pumps that source water from a borehole well and the distribution pumps that adds boost pressure. The majority of load will be exclusively operated during sunlit hours and the energy produced should be consumed directly from the output of the Fronius inverters while the remaining output will be used to slowly charge the batteries. The are a few small loads such as lights, a weather station and an alarm system that will be using the battery during the night as well as the residual consumption of the Quattros and Inverters.

When the main loads are not active the frequency shifter functionality should adapt the inverters output.

The reason for the post is to ask for comments on the setup, if anyone thinks there something I missed or any foreseen problems. Also I would like simplify the setup and use a single 3 Phase inverter, does Victron provide a compatibility matrix of brands and models that enable off-grid functionality with the Quattro.

Thanks a lot

Luis Fernandes asked
shaneyake edited ·

2 Answers

Off grid Quattro shuts down when Fronius stops due battery state 100%



New system with Quattro 8000, Primo 6.0 on ac out. When SOC reaches 100% and the fronius shuts down the quattro stops completly. All lights are off and no output. VE communications still works. Restart needed manual from the quattro and same happends when power comes back to the Fronius. Also strange that the loads are the same as the fronius output, but no loads are connected at all!

peterwolff asked
peterwolff answered ·

6 Answers

Can I combine EasySolar 24/1600/40 all-in-one with one Victron LFPSmart 25,6/100 battery ?

Hello, as a beginner I'm trying to design a simple system for off-grid use including:

- one EasySolar 24/1600/40 all-in-one Victron solution

- one LFPSmart 25,6/100 Victron battery with 25,6 V and 100Ah

- 4 x Sunpower Performance 375 Watts solar panels (Reference SPR-P3-375-BLK, each panel has Vmpp: 35.5 V, Impp: 10.57 A, Voc: 43 V, Isc: 11.26 A)

Would such a system make sense? Would I still need a BMS if I'm only using one battery ? Would I need to add anything else to such a system to make it work safely ?

Thanks for your help.

bouly123 asked
kevgermany answered ·

2 Answers

Grounding Off-Grid System - Some questions

Hello everybody,

in the past few months I've been designing the off-grid system for my farm, with the help of an electrician. I already bought (almost) all the components and I'm installing it right now.

Now, I find myself stuck with the grounding of the system, because I'm not quite sure how I should wire the whole system so that it's as safe as it should be.

As a side note, consider the following:

  • I know that it is advised to ask this kind of questions to a qualified electrician who knows the local regulations, but believe me, where I live (rural Panama) it's actually pretty hard to find one, let alone someone with experience with Victron products. In fact, I had to buy 80% of my components from the US because nobody sells them here. (for example it was literally impossible to find flexible wires, I had to buy them on Amazon. Same for 4/0 copper wire lugs and the tool to install them)
  • regarding local regulations, forget about it, there are no specific regulations and nobody checks whether what I'm doing is good or not. The person in charge in this town does not know anything about off-grid systems, and is in fact waiting for me to complete my system so that he can see how it works

I had some help from en electrician online, and of course I studied all what I could find online, but there are some things that I'm not sure about, so maybe you can help me out.

Please find attached the diagram of the system (It's a work in progress).

Electrical Drawing with 1x BYD LVL.pdf

I believe that the grounding wiring needs to be fixed, because:

  • 6 AWG for grounding the inverter is too small of a wire, because from reading Wiring Unlimited I think the wire should be tick enough to be able the carry the full current, which in my case is 250 amps, so the wire should be 4/0 AWG
  • it's not clear what happens between chassis grounding and AC grounding. Is it a floating system? Do I need one RDC before the AC distribution? Does the PV part of the system have a dedicated ground rod for lightning protection?

This is where I'm stuck.

From my understanding, I think the grounding should be fixed as follows:

  • the metal frames of the PV panels should be grounded with a ground rod
  • the ground output of the PV combiner box should be connected to the same ground rod
  • all the chassis of the components (the two inverters and the charge controller) should be connected in parallel with tick wire, and then connected to the central ground terminal of the Lynx Distributor
  • from there, I should run a 4/0 AWG wire to a ground busbar (not shown in the diagram), where I should also connect the grounding wire for the AC distribution panel
  • this ground busbar is connected to another dedicated ground rod
  • there should be a RDC breaker between the inverters and the AC distribution panel.

Well, there's that, not sure what I'm missing, but I'm sure that something is missing in my understanding of the whole grounding deal.

I appreciate any help!

Edit: I added a screenshot of the diagram.


niccolaiddis asked
shaneyake commented ·

4 Answers

Multiplus output only if battery is full

hey Everyone

I have a Multiplus 2 with a Cerbo GX. We are offgrid without a generator.
We would like to heat up our boiler, but only after the battery is fully charged. So on our surplus energy

I've thought the "output 2" from the multiplus would do excactly this.
Use all additional energy if battery is charged. But it seems i got this wrong. And that that is only triggered when you have other electricity coming in (not solar but grid/generator)

If Grid/generator is on > use Output 2.
If only battery/solar comes in > don't use Output 2

I need
If battery is fully charged > use Output 2.
If battery is not charged > don't use Output 2

Am I correct to think I understood the feature of Output 2 wrong?
And does anyone know how to achieve this what we need?

Thanks a lot!


Optionally: In this video you can see our full setup

dave-hakkens asked
pwfarnell edited ·

2 Answers

3+3kW AC coupled system design


We are designing 3+3 kW system. Because of financial constriction and pressing need to upgrade the current system we are planning to build our new system in two phases.

First phase would be 1 x Victron Multiplus II 48/3000, 1 x Fronius Primo 3.0-1 with around 4kW of PV, 320Ah 48V traction battery system (24 * 2V batterys) and Cerbo GX for system monitoring.

The second phase should be implemented next year. We would then add another Victron Multiplus II 48/3000 in parallel with the first one and another Fronius Primo 3.0-1 with around 4kW of PV.

This is a offgrid system, most of the power usage is during the day.

There is a 2kW generator for backup.

In addition to that we would probably add a micro water turbine (PowerSpout), also AC Coupled trough Ginlong Solis Mini string inverter. We could get from 500 to 1000W form the PowerSpout. I know that this takes the system over the 1:1 rule. But water turbine would be used when there is no PV power (bad weather or night).

I don't have the exact question, just need the sanity check for this long term plan.

Thank you!

mterman asked
shaneyake commented ·

0 Answers

Are 50vdc solar panels wasted on a 12vdc system?

Hi, I am just trying to get my head around this and wonder if someone can confirm it please?

For a 12-15vdc battery off grid system needing to charge through a charge controller via a solar panel array of course which the panels are rated at around 55Vdcmax.

With the cheaper Ebay MPPT controllers (link to example type bellow), they cut off the solar panels inputs if the solar panel voltages are above around 15Vdc, so effectively the panel would only charge the system when the panel voltage is within the 12vdc - 15vdc, effectively only for a VERY short time in the morning and again at sunset.

With a Victron charge controller like (link of example type below), to charge the 12-15vdc from the panels (55Vdc). Does the Victron charge controller cater for the full 0-55vdc from the panel or does it also have built in cut out solar voltage cut offs, resulting in the same issue as the cheaper Ebay charge controllers?

I guess I am looking to have some device which converts the 0-55Vdc to a more usable 12-15vdc range so as to charge the batteries. Is the Victron charge controllers able to do that, regardless of the voltage from the solar panels are producing?

Kind regards


John asked
gro edited ·

5 Answers

Intermittent VE Bus state OFF, no warnings. Lost power 30seconds

Any gurus out there have any ideas on this problem?

8kW Quattro, 7 x Pylontech Force 1, 2 x Blue Solar chargers commissioned this week. System ticks away quite nicely then randomly the inverter appears to switch off very briefly. Owner complains of losing power for around 30 seconds. Happened twice yesterday and twice the day before. Can see the event in advanced logging (VE Bus state briefly off) but no warnings generated. Rest of system unaffected. Doesn’t seem to correspond to anything unusual… no large loads at the time, etc. We’ve had storms the last day or two, not sure if this would be a factor. Anyone have any ideas??

timapex asked
dafyddhirst edited ·

1 Answer

RS 48/6000 and Pylontech batteries (how many?)

Hello everybody,

I have an offgrid installation with RS 48/6000 and 2x US2000 Pylontech batteries and I am wondering if two batteries is enough.

I can see that Victron has suggestion on how many batteries one needs for a properly functioning system depending on what Inverter/Charger one has. But the latest RS 48/6000 in not on the list!

It would be greatly appreciated if someone can provide any suggestions on how many Pylontech batteries are needed in a system with RS 48/6000.



Oleksandr asked
daniel87 commented ·

2 Answers

Is it advisable to use RapidShutdown Device on a Victron & BYD Off Grid System?

Has anyone try this configuration? Tigo Rapidshutdown devices installed in the PV Modules and an OFF grid PV system using VE Quattro, VE Smart Solar MPPT, & BYD LVL Lithium Batteries.

harry-chavez asked

0 Answers

DVCC in off-grid DC installation - "dynamic charge current"

Good day!

Looking at

Point 8.4.1 - sub-point "3"

"DC Loads are not accounted for. Even when a BMV or other battery monitor is installed. For example, with a configured maximum charge current of 50 Amps, and DC Loads drawing 20 Amps, the battery will be charged with 30 Amps. Not with the full allowed 50 Amps."

When or how can we change this? I cannot see why the DVCC cannot increase the current from chargers to compensate the loads and keep charging current at for example 50A.

Offcourse the idea works flawlessly in ESS configuration, but we do not have any inverter in the setup - but we do have high DC loads.

Any input or ideas will greatly be appreciated!


goose asked
mickwhitehead commented ·

0 Answers

What are the correct settings for an Off-Grid Victron Quattro 24/8000 & SMA SB5000TL-21 System

Can somebody advise the correct settings in the PV Inverter Support Assistant to control the output of the SB5000. The SB5000 ramps down to early and the batteries do not get enough charge.

Batteries: GEL 2x12V 250Ah in series and 3 sets in parallel.

SB5000TL-21 setting is Islanding 50Hz

Quattro Charger setting is: Absorption 28.8V; Float 27.6V. Max Charge amp are 75A.

The Quattro PV Inverter support setup is in default setting right now:













I contacted SMA. Their response is as follows:

Our island mode 50Hz is default to operate in between 51-52Hz for P(f): 100%-0%.

In this case you may want to change the frequency settings on the Victron to match our island mode frequency range.

karlheinzhaller asked
philmay edited ·

1 Answer

Pylontech (with needed ESS?) in an offgrid-installation


in the Victron product compatibility-list the pylontech batteries are listed to only can be used in an ESS-system. I think this is necessary of the CAN.Bus-Communication. This means that communication only works with the ESS assistant (why)?

I have to wait further 6 months for grid-connection to be built. For that time I want to build a small DC-Coupled PV and a Multiplus with Pylontech-Batteries. A big AC-coupled 30kWp-PV will follow next year. Since I wanted to install a Victron-ESS anyway I am wondering if I could use the pylontech also in an offgrid installation until the grid is ready?
Alternatively I wanted to install the ESS-Assistant offgrid and hoped i can use the pylontech without discharging them to 0% when grid isn't available at no time. I also don't know if a generator would be accepted in the AC-In then when a grid code has to be chosen.

I red that ESS shouldn't be used in an offgrid-installation neither. I know that ESS doesn't make sense in that situation, but it has du be used to use the pylontechs?
So is there a solution to use these components until grid will be available?

Thank you!

porcini asked
christian-valdivia commented ·

4 Answers

Which inverter for off-grid (to complement existing one?)


We have a permanent off-grid installation in a garden in Germany (no grid, no generator) with 7 kWp solar and a 24V 12 kWh lead-acid battery (so around 6 kWh usable).

We currently have a MultiPlus Compact 24/2000/50-30. Which has a nice low standby consumption, which seems to be important in the winter.

But at least in the summer the 2000VA of the inverter is too small for us, as we have a lot of solar and also some consumption:
1-2 fridges running, some times a pump for irrigation, the occasional lawn mower and we like to use an electric stove for cooking and baking. And the inverter shutting down due to overload is always a pain. Electrical car charging is also nice.

Now, we were thinking about 1-2 multiplus 24/5000 or about 1 quattro 24/8000.

Is it possible to normally have the existing multiplus 24/2000 running (for the low idle) and switch on the quattro automatically, maybe using PowerAssist?

Or should we rather get rid of the multiplus 24/2000 and have two multiplus 24/5000 running in parallel?

Do you have similiar installations? What would you buy?

hedwig asked
ddickov edited ·

2 Answers

Quattro 10k overload fault, fire risk

Quattro 10k professionally installed March 2013. Off grid system, traction batteries 48v. Solar power 10 kw, 2 Sunnyboy TL 5000. Power failure at 0830 hrs August 2019. On investigation Quattro indicated an overload condition. (At this point in time basic load including 3 refrigerators could have been operating. All occupants of house in bed alerted by security system indicating a mains failure condition “No real load”. On advice from installer all AC output from Quattro turned off. All PV input systems shut down. Only power to Quattro was now DC at around 49 volts. Overload condition remained, indicated by overload LED. Attempted reset by turning Quattro to off position waited 5 minutes then turned Quattro on to Inverter mode. Quattro reset with no overload indicated. Waited a a few minutes then turned load back on to inverter. Same load as before (Virtually no load) system was working as expected. Ensured load was restricted for a while to ensure no overload possibility. All seemed to be working as designed. Returned to check system 15 minutes later and found the Quattro was indicating overload, making a horrible grinding sound and smoking. I isolated system by shutting down all AC load, shut down PV system and isolated battery bank.

This system has been well maintained, never overloaded and the room where it lives is cooled in summer to avoid overheating.

Very disappointing that the Quattro actually flamed out after 6 years. Contacted the closest Victron service agent. He didn’t sound surprised At what I had explained and mentioned “short circuit”.

This unit is not that far out of warranty and I am expecting no joy from the agent. I was surprised to read of how many instances where the overload situation has occurred with Quattro and Multi units. Seems this sustainable energy thing is very expensive especially if things catch on fire.

Any help would be appreciated in helping me understand how this unit could work well for 6 years then almost catch on fire. I would have thought protection would have been built in to avoid this situation.

Brad Dull asked
Brad Dull answered ·

4 Answers

How can I prioritize MPPT DC Solar over Generator in Off grid application

Hi community.

I have got a large number of Victron-Pylontech off-grid systems with Smartsolar MPPT installed. The inverters and MPPT are programmed as per the victron-pylontech instructions . As these are off-grid installations with generator, I can not run ESS assistant.

I have realized that when solar power is available but the inverters call the generator because the load is too high, as soon as the inverters sync with the ac source, the inverters take all the charge and the MPPT DC charge goes to something neglectable. When the inverters stop syncing with the AC source the solar power raise again. Needless to say this is not desirable and client not happy with it.

I have seen others threads with similar problem but honestly a lot of ramblings and not really any clear solution.

The questions I think it is very simple. On an off-grid installation (with no ESS Assistant), How can I prioritize DC Solar over Generator?

Jesus Mazo asked
Alexandra commented ·

2 Answers

Sonnenschein@home, Cerbo, 15kva Quattro, SmartSolar Ve-Can 150/70 issue Nothing Charging

This is an off-grid install.

Firmware of each unit has been updated and confirmed

I've enabled DVCC / SVS and such as was discussed on the 2019 " DC coupled MPPT & Multiplus with Sonnenschein @Home Lithium managed battery" forum post.

All unit show on up on the Cerbo GX ( battery, Quattro, CC ) But nothing charges the battery. CC shows it's externally controlled with charge settings, etc. but it doesnt seem to get the " Go " from the battery/BMS.

Same with the Quattro, I've set up unit using the VE-Configure. Turn on the genny, shows voltage, relays click but never locks.

Is there a setting that I could be missing? Or something changed since 2019?

I find it strange I cant get any charging method working. Points me toward a Cerbo setting incorrect.

The battery shows on the Cerbo and I have Can traffic TX/RX. The Supplier and I have been tring all sorts of different things over the last 2 weeks with no luck.

chris-2 asked

0 Answers

Dc coupling off grid system

Is there a rule between PV size on Solar chargers and the inverter/charger?

For example, I have a system of 6 Quattro 15 KVA and 19 MPPT Rs 200 A.

abdallah-salamah asked
shaneyake answered ·

1 Answer

Cerbo GX required for off-grid system?


I have a solar off-grid system for a house. I have 4320Wp of solar and using 250/70 smartsolar mppt and a 5KVA multiplus 2 inverter.

My question is that am I required to add a cerbo GX or the system can work properly without it?

assaadeldleptany asked
Vance Mitchell answered ·

1 Answer

Proposed Off-Grid Layout

Hi all,

Thanks for the response with the CCGX defining points for chargers, looks like I should have rtfm in the first place.

I've come up with a modified version of the "MultiPlus system example 3kW-24V-120V AC" system schematic. It's a small cabin with only small AC loads with a generator for supplemental charging needs during low solar generation. Sharing it with the community to see if I'm getting something very wrong and need to change my parts before ordering.



Cabin Layout.pdf

andrew-butler asked
hoeken answered ·

1 Answer

Is ther a better use of solar power in an offgrid system

I am struggling with the correct settings of my solar offgrid system.

System setup:-Multiplus II 48/3000/35, Smartsolar 150/35, Color Control GX (DVCC enabled - charge current limit at 35A, STS, SCS and SVS enabled), BMV-720, 6x320W solar panels, 48V/7000Wh Li-ion battery.

Float is set to 54V and Absorptium is 56,8V (standard settings for Li-ion). When battery is charging, then solar is used for direct consumption an the rest is used for charging. But when the battery is fully charged, MPPT goes in to Float state and the solar current is 0 and all consumption comes from the battry. The next morning a new cycle is started (Bulk-Absorptium-Float). During the summer the solar power is higher than my consumption so it is not a problem, but during autumn/winter it will be.

Is this normal or what can I do to maximise use of the solar panels?



tore asked
tore commented ·

2 Answers

Combining AC coupling and DC coupling off grid system

Are there rules to combine Fronius inverter ( AC coupling ) with Solar charger ( DC coupling ) other than rule 1.1 in the ac coupling side ?

abdallah-salamah asked
shaneyake commented ·

2 Answers

Quattro 10kva 3phase system - Swells and dips over 10%

*****System: Off Grid

3 x Victron Quattro 10kva

1 x Fronius 10kW Symo - 1 x 20kW Symo

18 x Pylontech US 3000

2 x Skylla 48v 50ah AC chargers ( Supplement charge for batteries )

84 x 410w JA Solar Mono half cell

System was installed on new build home. We experienced dipping in the lights. The electrician has done a logger test last week and the results are a bit concerning. Lowest dip recorded was 180v ( 10 - 60 milliseconds), and it regularly dips below 10%, 207v.

Highest swell recorded 257v (10 - 60 milliseconds )

Attached logger data and Victron data ( 1 min intervals )

AMSO 1216 JNF Electrical.pdfHuis Visser Statistics for week 21 May to 28 May 2021.pdf

L1 (Victron) - Phase B (Logger Test)

L2 - Phase C

L3 - Phase A

The underfloor heating runs on Phase C (L2). It switched off on Tuesday morning and technicians are coming in to have a look.

My question is, has anybody experienced a similar situation? Is there a way to minimize the shifting?

Thank you



* Results of second test. First 36hrs main DB incoming 3 phase line from Off grid system. Last 36hrs directly on Victron output and termination boxes. (This was done to check that data corresponds and we have no other electrical problem in-between DB and Inverters.)

AMSO 1217 Test 2.pdf

Results are still the same.

*The underfloor heating has been fixed. Unrelated issue

* We have done a firmware Quattro's and N-E bond in the termination boxes. ( This was done before new logger test was done)

* Lights are more stable. Flickering only happens when sun is going down, load increases and the shift happens between Fronius not being able to supply sufficient power and the batteries taking over (100% SOC) I will follow up with Fronius to see if there is a fix for this. ( I have upgraded the Fronius to latest software)

* My question is: The fluctuations are very short in duration 20 - 40 milliseconds. On average we remain on 230V. I do understand being fully of grid will make the voltages fluctuate. Is this in normal parameters? Is there a way to minimize it? Will it have a negative long-term effect on household appliances?


johanh asked
tozz commented ·

2 Answers

#1 Device switched off

Hi All

Looking for some brainy Victron experts to help me with a problem installation. (Background: I work for a company that installs alternative power systems and we install 5-6 systems a month, predominantly using Victron Energy equipment)

The setup:

3 x Quattro 15kVA in an off-grid application using AC & DC-coupled solar on a Pylontech battery bank.
4 x Victron SmartSolar 250/100 Solar Charge Controllers
1 x Fronius Symo 15.0 AC coupled PV inverter
12 x Pylontech US3000 Lithium Batteries
Victron Cerbo GX with Touch Display

Setup: Off-Grid with a generator (80kVA)
PV Inverter Support Assistant installed

I get sporadic occurrences of notification #1 Device Switched Off, where the Phase 1 master inverter simply switches off.

What I have tried:
1. I have updated to firmware version 476 and replaced all VE.BUS cables with Victron supplied cables.
2. I have also tried replacing the phase L1 master inverter with a new Victron Quattro 15kVA Inverter.
3. I have tried to analyse all the available data on VRM, but I cannot see any drop in DC bus voltage, an overload from AC output or excessive generation from the Fronius PV.

When it occurs, all of the LED's on the Phase L1 Master simply go out, and the other two inverters present an LED sequence indicating that they are missing (not detecting) the master.

30s later the Phase L1 master restarts and the 3 inverters begin inverting again. No alarm in the VRM alarm logs. Only a notification on the Victron Cerbo GX indicating #1 device has switched off.

Would really appreciate some help.

Nicholas Herbst asked
jbsnyma answered ·

3 Answers

MyPV AC-Thor in off-grid system - settings?


the manual ( ) says that when using AC-Thor in an off-grid system frequency shifting (PV-inverter assistent) has to be activated at the Multi.

- Is this also necessary if only DC-coupled PV is used (no PV-inverter on AC-out)?

- what are the frequency settings in the "PV-inverter" assistent? Are the default-settings ok?

Best regards

e-box asked
Robert Bazalgette answered ·

4 Answers

Solar inverter does not like MultiPlus-II impedance

I have two solar inverters connect to the "critical loads" output (AC-OUT1) of the MultiPlus-II in an off grid situation. This means the MultiPlus-II is disconnected from the grid, i.e. nothing connected on AC-IN1.

The inverter of the MultiPlus-II is providing a stable 50 Hz 230V grid on AC-OUT1 so the solar inverters are seeing a grid (provided by the MultiPlus-II) and are powering on. They "monitor" the grid for about 30 seconds like usual and then they should switch to producing energy and feeding it back into the grid. At this point however, both the solar inverters display a similar error message.

Zac-Bfr at <some value> Ohm

According to, this indicates that the impedance of the grid (provided by the MultiPlus-II) is too high.

The solar inverters then shut down (or re-initiate), monitor the grid for some time and end up display the same Zac-Bfr message with a slightly different impedance value in Ohm.

I have tried connecting only solar inverter 1 or only solar inverter 2 to the MultiPlus-II but the result remains the same Zac-Bfr message.

Why don't my solar inverters "like" (the impedance of) the MultiPlus-II grid and what can I possibly do about it?



bjorn-n asked
bjorn-n commented ·

2 Answers

How to get Venus GX to show two LG resu 6.5 batteries at the same time

Hi All, we have an off-gird system using two LG resu 6.5 batteries in parallel with each other which is monitored with a Venus GX. The LGs also get tied to a large AGM setup at certain times of the day to share the charging. Overall the system is monitored and controlled by many Sonoff switches and a few Orange Pi's running a common bash script which works pretty well for us.

One very minor outstanding issue is the Venus GX only shows one LG battery at a time. If we unplug a canbus cable from one of the batteries, the VGX will show the other and vice versa, but the VGX will never show both at the same time. The VGX shows them both as Product: LG resu battery and Product ID: B004. Is it because they have the same product details? Do they need to be daisy chained rather than each connected directly to a canbus port on the VGX?

Its surprising the VGX can't tell it has two batteries connected to it..

petekat03 asked
petekat03 edited ·

0 Answers

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