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Modbus TCP

Pylontech Modbus Addressing Recovery

Hello everyone,

I'm doing a large installation that consists of 242 Pylontech US5000 batteries. For maintenance purposes, it seems important to us to be able to act quickly on a defective battery or one that has a too high temperature for example. Unfortunately, we have not yet been able to find a solution that would accurately indicate a defective battery.

Recently I noticed that the remote console was indicating the address of the coldest/hottest battery or the lowest/highest voltage battery as shown in the attached picture.


Max cell temperature : Battery 0101 - 19°C

If the Cerbo GX indicates these addresses, there must be a way to retrieve all the battery addresses. In this way we will be able to associate the address of the battery with its number and its location in the battery bank.

For the communication with the batteries we will use several LV Hubs. The next step will be to ask Pylontech how the addressing of the batteries is distributed.

Do you have any idea how I can enter in the Cerbo GX and retrieve the address of a battery? I will also need to find a way to display the temperature status of each battery in the VRM...

I have never tried to get the Modbus address of the batteries so I don't know yet the tool to use for that... Can you direct me to the method?

I saw that there is the Node-Red tool but I don't know if it will be able to help me and I haven't dug into the possibilities of this tool yet.


cryptom asked
cryptom edited ·

3 Answers

SolarEdge SE3680H via SunSpec to GX Device

Hi all,

I've connected one SolarEdge SE3680H by means of ModbusTCP / SunSpec in summer 2021 to my OctoGX. I configured it by means of the Victron manual and everything went quickly fine as below.


The current issue started when I added a second SE3680H this year 2022 in February. The GX device (2.85~1) was not able to detect both inverters but data of first one was still shown.

Thus I checked the settings of the first inverter for comparison and was forced to perform a firmware update by means of "SetApp". After this firmware update now both SE3680H are not detected by the GX device and both are not shown via the GX device, although the first one was previously working well. (see screenshot above).

So, I suppose it has something to do with current SolarEdge firmware but maybe as well (or)with Victron GX firmware because in Summer 2021 I was running the current one at that time which was 2.7x I suppose.

So how to debug this issue? I was searching the web for a SunSpec browser and found the one from the SunSpec alliance but for downloading you need to be a member of the alliance :( and membership of $4000 is quite out of scope for me.

Therefore please suggest an easy debug method to verifiy if the SE inverters are providing data via ModBusTCP correctly. (eg without involving the GX device).

@mvader (Victron Energy) If you could find the time to take a look at this issue, I'd be very happy! Installation name is "FH22" and remote support tunnel is active. Feel free to scan for the SE inverters, they should be correctly configured. There local IPs are and

Best regards,


matthias-roetzer asked
matthias-roetzer commented ·

3 Answers

2 Grid meters connected to Cerbo GX

Can anyone please help me with this!!

I have two grid meters connected to my cerbo GX.One is connected directly to the grid and the other one is connected to the multiplus end point to see how much I'm charging and discharging. How do I choose what to display on the HMI of the cerbo gx. because when they both are connected the HMI shows both at the same time and the results of the HMI jumps between both gridmeters without any control.

alawwirbilal asked
alawwirbilal commented ·

1 Answer

Victron integration with home assistant using Modbus TCP

I'm currently trying to integrate my victron setup into home assistant, but when I turn on the Modbus on my CCGX I keep getting the message:

ERROR "Error processing function code 3, unit id 126, start address 40000, quantity 2, src Modbus address 40000 is not registered"

My setup is a MG50 with fronius 8kw, victron mppt 250/100, 10kva Quattro, 13.8kwh BYD LiFePO4 battery, CCGX with firmware version v2.73.

Please any idea on how to resolve this?

ijeamaka-omayeka asked
marcus-spranger commented ·

3 Answers

Enabling Modbus TCP in Cerbo GX triggers error due to access of address 40000

This has been asked before here:

but there has been no real answer unfortunately so I am trying again.

I would like to use the Modbus TCP interface to read out and monitor various values of the system, which consists of:

  • 2x MultiPlus II 5000
  • Cerbo GX (firmware version 2.84)
  • 2x Freedom Won batteries
  • Fronius Primo 8.2
  • BlueSolar Charger MPPT 150/35

As soon as I enable the Modbus TCP service, there seems to be a device making a query for address 40000, which doesn't exist:


This request seems to happen about once per minute. Not sure which device has unit ID 126, but the IP address is the address of the Cerbo GX.

How can I turn off those invalid queries resulting in that error?

Thank you.

marcus-spranger asked
marcus-spranger edited ·

1 Answer

VenusOS, Modbus and compatible devices (Heatpump Ecodesign ED 180RF)

Hello everyone,

I am an enthusiastic VenusOS user managing 2x systems based on it. Currently the systems are fairly straightforward with solar panels, Lifepo4 batteries, MPPTs, and inverters.

Now I find myself in the need to add a heat pump (Ecodesign ED 180 RF) for hot water production and I was wondering about compatibility/interfaceability.

The manufacturer tells me it has Modbus interface and that it is compatible with all systems supporting this bus. In this case, the interface would allow to readout values and set thresholds.

My question is whether anyone knows if this is supported by VenusOS (via RS485-USB converter). Or actually whether in general hot water generating systems are supported and can be monitored within VenusOS. Off course, if this would be even accessible within Node-RED this would be the cherry on top ;-)

Thank you in advance for your inputs!


dgnoise asked
dgnoise answered ·

2 Answers

Siemens PAC2200 Grid Meter Modbus TCP


I have a Cerbo GX.

I would like to use my Siemens PAC2200 as grid meter for my GX.

Is there someone how has experice white this and help me connect this by modbus TCP?

Regards, Niels

niels asked
Warwick Bruce Chapman answered ·

2 Answers

Janitza UMG604E connected by modbus to 6 Quattro48/8000 for self-consumption system


This is the setup I am thinking of for a costumer running several PV plants. We want to add batteries for pure self consumption and charge only when PV is feeding to the grid. For that reason we want to get the current of every line from a already existing Janitza UMG 604 E via modbus TCP. Is this working? Where to read about the setup? Thanks in advance! Answers in German also welcome

marco-steurer asked
skyme edited ·

0 Answers

Utiliser Linky comme compteur d'energie


je dispose d'un véhicule possédant une installation solaire (BMV 702, Multiplus 800Va, MPPT 100/30, MPPT 75/15, VenusOS) et pour lequel j'ai configuré l'assistant ESS. une simple rallonge est branché entre le véhicule et le logement dont je suis locataire.
Le mode ESS marche a merveille ! Je souhaiterais pour ne pas modifier le réseau électrique existant du logement utiliser les données fournies par le compteur Linky afin de transmettre ces dernières à l'installation solaire afin de limiter la quantité de surplus injectée dans le réseau. Je sais qu'il existe l'ET112 pour ce genre de cas mais je souhaiterais ne rien modifier et donc utiliser la téléinfo du linky pour récupérer L1 et ensuite le transmettre au VenusOS via modbus pour piloter l'assistant ESS.
Quelqu'un a-t-il déjà mis en oeuvre ce genre de chose et pourrait m'aider à reproduire celà ?Je suis inculte en python et modbus donc un p'tit coup de pouce serait vraiment apprécié ! D'avance merci à tous pour vos retours !

vanupied asked
chuff edited ·

6 Answers

connection between Si-RS485 and CCGX


Trying to connect a Ingenieur buro Si-RS485 to VRM. Setting:

Si-RS485 ---- > 12V from 24 to 12V transformer and RS485 to USB cable 5m (VE bus Multiplus V 430) -------> USB 12m self regenerating -------> CCGX (V 2.91) -------> Modemrouter -----> 3 and 4G ----> Internet ----> VRM


No answer from VRM,

Impossible to use Modbus setting from a PC attached on same network


Not a specialist, just a self trained Victron's user


Any tip???

Lionel SEYDOUX asked

0 Answers

Can a Multiplus 48v 800va be used as a charger only to supplement an existing ESS?

I currently have an existing Multiplus II GX 5kva with 20kWh, 48v batteries in grid connected ESS charging mainly solar and also a 4 hour off peak electric when the batteries are low. The issue I am starting to find is the 4 hour window is not long enough to charge the batteries (3.3kW max charge rate) so I am looking at other options on how to inject more energy into the batteries within that 4 hour window. The obvious cost effective solution would be another 48v charger timed to come on during this 4 hour period set to shut down at the same voltage bulk finishes on the Multiplus II GX.

My question is can this be done without issue or is anyone aware of any issues in doing this?

Is there a better solution? I do also have a cheap 24v 3kva inverter charger with lead acid batteries doing nothing much at the moment and I also thought about maybe using a 24v to 48v charger? Any way to connect a bus controlled 24dc-48dc charger to my existing Multiplus II GX?

Jason - UK asked

0 Answers

when will victron reduce the number of incompatible networks?

Is it really necessary to have



All incompatible, some using the same connectors with warnings not to exchange the cables, some with termination, some without?

CAN without VE. Should work for all, reduce the costs for victron and the customers, reduce the problems and complexity of the systems.


ludo asked
wkirby commented ·

9 Answers

Multi RS - MyPV AC-THOR - DC-Coupled

Dear Community

I have a Multi RS Solar, 2x SmartSolar MPPT 100/20, 14kWh LiFePo4 Battery and an AC-THOR.

The Multi RS can´t feed in and it is always connected with the grid as backup. That means it can´t work with frequency shift.

I have tried with "Adjustable Modbus TCP", but I can´t get it work properly. I have the "CCGX-Modbus-TCP-register-list-2.80.xlsx". I managed to play around with some Register.

My goal is to controll the AC-THOR somehow with the battery power register. If the battery is full the AC-THOR should use the "PV - DC-coupled power (850)".

Unfortunately my system seems to be unique.

Does anyone have an idea how to get it working?

ubi asked

0 Answers

Modbus TCP Tank sensor.


I have a DIY tank sensor that records tank levels to my home automation software of choice (Openhab). Is it possible to send that data to venus os raspi/VRM via modbus tcp? I had a look at the registers and it seems it's not writeable but wasn't sure if I was misunderstanding?



matt1309 asked

0 Answers

CCGX - DVCC -> How to Limit Charge Voltage using ModBus-TCP

I've noticed the addition in DVCC the ability to limit the managed battery charge voltage to a value of my liking. I am very happy, that this is finally possible now.
Now, I would like to set this maximum charge voltage using Home Assistant.

Inside my Modbus TCP services, I have access to
According to CCGX-Modbus-TCP Register-list.xlsx, the only writing-enabled registers are the CCGX-relay-states.

Is there any possibility set the Maximum Charge Voltage per Modbus TCP from Home Assistant? If yes, what is the register of this service?

Michael Timler asked
Michael Timler edited ·

2 Answers

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