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PASSIVE ERROR - Problem to get communication started between Multiplus 2 GX and BYD B-Box BMS

Dear Forum,

hope you can get me some hints regarding the setup between BYD B-BOX (L3.5) BMS and Victron Multiplus II GX (3000er), which I bought new.

I recently bought the BYD B-BOX battery used from another user who had it running with a Victron Multiplus but now switched to PylonTech.

My setup is as following: MPPT SmartSolar DC connected to battery (short test: charging works, as indicated by the BYD battery (low rate white LED flash and battery voltages are in a reasonable range) and Multiplus GX connected to the battery.


Actually, I not have AC-IN connected to the grid nor the EM24 (my electrician will do that next week). Connection with SmartSolar via the VE.Bus worked very nicely. Also I follwoed the video instruction of Guy to setup the Victron for first Multiplus setup (setting to 500kBaud, DVCC, etc). I used a Typ A cable for the CAN between BMS and VE.CAN. I have an end plug / resistor on the VE.CAN as well.

Status message after reboot the Multiplus is: Not connected. In the BMS-CAN port i found following error message: Error-passive TEC:0 REC:128. Some Multiplus continues pushing packets. See the screen shot below:


Do you have any hints which root cause the error message may have?

Thanks for your support!

uksubs asked
uksubs answered ·

2 Answers

Errors 2 and 29 on MPPT RS charge controller with BYD battery

Hello colleagues. We use BYD batteries in most of our installations. On some of our systems, after commissioning or adding new batteries, we get BYD high voltage notifications in the "Remote console" (screenshot 1). This is not a critical error and is not written to the "Alarm logs", but it does make our customers worry.


In reality, the battery voltage is far from the permissible maximum, and if you go to the menu of the battery itself immediately after receiving the notification, you can see that all the parameters are normal and it works fine (screenshot 2).


It's just that while the batteries are new and the cells are not balanced enough, the Victron system interprets this as a "high voltage" of the entire battery and starts to warn about it in this way. After a couple of weeks or months, these notifications stop. A similar problem is described here using Pylontech batteries as an example:

But lately (and only on some new systems) we are facing more serious errors 2 and 29 on MPPT RS charge controllers. I can't figure out why this only happens on some systems even though the settings we make are the same. I know that the PV voltage at the input of the MPPT RS should not exceed 8 times the float voltage of the battery, and we are far from that limit. Firmwares on all devices in the system are updated to the latest versions, as well as Venus OS. DVCC is enabled.

On one of the systems there was error 29, I carefully checked all the settings and, not finding any deviations, left the system running in this state. As a result, this error stopped appearing after three weeks (screenshot 3).


A couple of days ago we started a new system with an RS controller and a BYD battery and I see errors 2 and 29 again (screenshot 4). When I look at the battery voltage charts in the "Advanced" section, I see perfectly normal values (screenshot 5), but when I go to the MPPT RS menu in the "Remote console" I see a very high battery voltage (screenshot 6). Where does it come from? This value conflicts with all settings. At the same time, there are no errors in the menu of the battery itself. Maybe there is some problem in communication between BYD equipment and Victron?




I understand that it is possible to limit the voltage in DVCC, but on most of our systems (with the same set of equipment and settings), there are no such problems. I don't want to do many individual settings for the same systems, it can be confusing.

I will be glad if Victron employees or installers who successfully coped with this problem answer.

romarub asked
Daniël Boekel (Victron Energy Staff) answered ·

3 Answers

Is anyboby using Byd LV Flex5 lithium batteries. Problem with charge derating.

The system consists of 6.6Kw of solar connected to froinus 5Kw grid inverter which is on the output of a Multi Plus II GX. The batteries are 2x Byd LV Flex5 and 1x BMU. The system is off-grid.

The problem is that the CCL(charge current limit) is set to 26.8 amps when the battery temperature is 15degC or below. The manual states charge derating occurs between -10 and +5degC. The firmware verisons for the battery are BMU 1.22, BMS 1.13 and parameter table 1.4. Does anybody have LV Flex5 batteries with this issue?

gavin asked
gavin commented ·

2 Answers

Blackouts in off grid installation. With grid inversors.

Good morning

We have problems with blackouts in a off grid installation. We have thisproblema in two systems and in both of them we have installed BYD LVS batteries.

This system it has a Victron Multiplus 10000/140, 4 BYD LVS batteries, a grid inversor Kostal Piko MP 5kw and a Victron color control.

With the batteries at 100% of SOC, after 2 hours aprox the system make a blackout. We don’t know the cause, we try go down the bulk voltatge at 55,4V because we have a hight voltatge warnings.

We have charging the AC current assistent and the PV iverter assistent. We attached the frecuencies configuration.

You know the cause that can cause this blackouts? We have the same problema with another installation, the differences is that the grid inversors is a Sunny boy 6.0 and also there are 6 batteries and a Victron MPPT 450/100.


Also, attached the grafics where it can see the blackouts.





puigverd asked
Guy Stewart (Victron Community Manager) answered ·

1 Answer


Bonsoir à toutes et à tous,

J'ai du pousser une de nos BYD LVL 15.4 dans ses retranchements et je suis un peu étonné...

BYD indique que l'End of discharge voltage(V) de la batterie est de 40 V.

Or en consultant mes données, je vois que j'ai un SOC à 1 % avec une tension de batterie à 50.78 V, donc bien loin de l'EODV et de ses 40 V.

La batterie a donc continué à fonctionner pendant plus d'1h30 (je n'ai pas poursuivi le test au-delà) avec un SOC qui restait à 1 % avec une tension comprise entre 50.88 V et 50.78 V.

La question est donc, pourquoi le GX indique un SOC de 1 % (si longtemps alors que la baisse est constante en 99 et 1 %) avec une tension à 50.78 V, là ou l'EODV est à 40 V ?

Merci !


elbarjo asked
elbarjo commented ·

4 Answers

Baterist byd LVL can not charge and discharge.

Hello everyone, we have established a system in turkey. In the system, there are 3 units of quatro 48/15000 in each phase, also mppt charge 150/85 x 6 units, Fronius eco 27, symo 20 and symo 10 available, lastly BYD LVL 15.4 kWh x 10 units available. all installations in the system are ok, but the batteries are not charging and discharging. Although the battery status shows 49% on the screen, the charge does not show any current, but it reads the voltage. I'm looking for help on this matter.

veliozbek asked
Guy Stewart (Victron Community Manager) commented ·

5 Answers

Multiplus-II GX throttling down PV inverter on grid loss

Hello all,

I have a grid-tied home ESS system with a MultiPlus-II GX, a PV array with a Fronius Primo inverter on AC OUT, and a BYD battery connected to the Multiplus.

Each time there's a grid loss (happens very often over here) all the PV power from the Fronius inverter is instantly throttled down to zero, even in case of full sun exposure. Consequently, for all the duration of the grid loss, all the backup power is provided by the battery only.

I have the feeling it's just a waste of solar power. Why can't the Multiplus allow the Fronius inverter to continue its operation in case of grid loss ? Its power added to the battery power could sustain much more loads than just the battery alone.

Is that a bug, is there a reason, or am I missing a hidden setting somewhere ?

Thanks everybody for your insights.

Pierre-Marie Baty asked
Pierre-Marie Baty answered ·

2 Answers

ESS battery level charging and inverter own consumption

Hello I'm quite new and Victron system was started only few days ago. But I'm observing few unexplained situations. Maybe you can help me.

1. Battery ignores minimal SOC (set to 10%) continues discharge until 5%, then starts charging from grid with 4kW until it reaches 10% and then continues with cca 500W to charge until 13% and then starts again discharging.

1.1. I was thinking that when it reaches minimal SOC it will go to idle and stay there until charged by solar panels, what I understand wrong?

1.2. I was thinking that when grid charging is disabled it means battery is not charged from grid, what I understand wrong?

2. If I look at VRM portal I see Grid, AC loads, Battery, PV charger, but when I calculate the sum I miss 100 to 500W, is this own consumption of Victron equipment? (you can calculate from any of the pictures, discharging 'misses' 109W, Charging1 382W, Charging2 188W)

3. UPS functionality does not work, by power outage lights stay, but clock and remote switches got reset, is there a way to fix this?

My system: 16x IBC solar 450 Wp, 3x Victron Multiplus 5000 (three phase setup), 2x Victron MPPT 250/70, 1x BYD LVS 4kWh, 1x Victron color GX

Attached pictures:

Discharging.jpgDischarging: Battery discharging even under 10%
Charging1.jpgCharging2.jpgCharging: How the battery is charged from grid
Expected.jpgExpected: This is what I expect to see when battery is less than 10%, please compare with Discharging picture

Thank you


peter79 asked
peter79 edited ·

3 Answers

Off grid upgrade/extension suggestion


Looking for some ideas on how to achieve an extension/upgrade to an off-grid system.


3 years old.

15kVA quattro

150/100 MPPT

Fronius primo 8.2

13kW PV

DC and AC coupled system.

8x BYD B-Plus 2.5 (20kWh total)

We wish to increase the battery capacity however stock of the same type is hard to get. Don’t wish to replace original batteries at this stage.

Also wish to increase the solar, no issues there.

Open to adding another Quattro and therefore having higher power available in the system, along with a new additional battery bank, additional MPPT and extra solar.

Is this our only option, or there any other methods of adding capacity we should consider?

bmc123 asked
Daniël Boekel (Victron Energy Staff) commented ·

1 Answer

MPPT 450 200 RS BYD High Voltage Alarm

Dear Community,

I have an issue with ESS system, the system is DC coupled solar system with the following:

  • MultiPlus II 48/8000/110-100
  • MPPT RS 450 200
  • Cerbo GX + Touch
  • 8 x 5kWh LV Flex Lite
  • normal protections with by pass change-over switch

So, I programmed the system in ESS mode with all parameters checked... when the batteries are full I am receiving an alarm on the Cerbo "BYD Premium LV battery High Voltage" I guess the BYD BMU is sending this alarm to the cerbo.


Everything is working fine. I can see the alarm when the battery is full. So, maybe there is a delay in the MPPT or the BYD BMU parameters have to be adjusted. if you have the solution then please share it.

Thank you in advance,

M. K. asked

0 Answers

Throttled Fronius wastes up to 90% of capacity - improvement required on Zero-feed-in

Hi All,

With this documentation I like to demonstrate that Fronius Zero-feed-in algorithm ignores up to 90% of available energy in a zero-feed-configuration, although all produced energy could be fed into battery at that moment.

@Victron&Fronius-Developers: Please read this article and translate improvements into next software releases.

Generic problem description

My PV panel power balance between MPPT-fed and Fronius-fed energy ratio is about 45% vs. 55% (my complete topology is described below). This screenshot demonstrates that this ratio can be also effectively generated and loaded into AC-IN and battery as long as the grid is disconnected from MultiPlus-II.


Only 30 seconds before when grid was still connected, I took that screenshot. You see that MPPT has nearly the same output, but the Fronius delivered only 28% of its actually currently possible capacity. Since the previous screenshot was taken before, it demonstrates clearly that at that moment there was no restriction of the battery taking additional energy (charging limit of 242A current allowed by BYD at that moment of time).


Frist conclusion
Fronius Zero-feed-in feature in Victron ESS wastes plenty energy (>75% in average – up to 90% in peak)

Closer analysis
Following analysis demonstrates that Fronius Zero feed-in mechanism only works as long as you have a steadily deviating power consumption. Otherwise it wastes plenty energy.

1. AC load on AC-OUT consumption is currently low at 249W and Fronius feeds in with 934W only (compared to screenshot in step 3 you see that was is only 50% of the available capacity at that moment).


2. Switch on a mentionable load on AC-OUT1 activates the Fronius within a few seconds to leverage full available capacity.


3. After having switched off the additional load, Fronius continues to produce similar but already slight lower volume. The produced capacity is fed mainly into battery.


4. As long as there is no peak any more on AC-OUT1, Fronius lowers its production steadily down. In that example its returned to 23% of currently available capacity.
Battery SOC was 52%, the currently applied current 52,9A with readiness to take 242A at that moment.


Please improve zero-feed-in feature so that also battery will be effectively loaded with available capacity on Fronius attached PVs.

My environment

  • MultiPlus-II 48/5000/70-50 in 3-phase (firmware 477) with a ESS zero feed-in configuration
  • ESS zero feed-in configuration
  • Multiphase regulation on single phase
  • Grid setpoint defined at 80W > currently returned to 60W again
  • Fronius Symo 6.0-3-M (firmware 3.16.7-1) with 6.030 kWp attached (55% of total PV) – connected to AC-OUT1 (critical loads) – no additional smart meter - sunspec activated
  • Victron MPPT VE.can 250/100 rev2 (firmware 3.02) connected via VE-Bus with 5.025kWp attached (45% of total PV)
  • PV modules all with absolutely identical direction and no shadowing
  • BYD LV 15.4 (allowed charging and discharging current during the test procedure 243A)
    BMS connected via CAN-bus (firmware 1.16)
  • VenusGX (firmware 2.60) > currently tested with 2.62-beta5
  • Any component with latest firmware as of today


thomasw-1 asked
ccc-telecom answered ·

7 Answers

BYD LVS High voltage warning on Remote console

I have an offgrid system with a Quatrro 48/8000, MPPT 150/70 and Fronius Primo 5.0 on the AC output.

Charging parameters for the Quattro and the MPPT are entered as the victon-byd instructions demand.

The strange thing is that I receive High Voltage warnings from the BYD BMS on my Remote console. Why is this happening? The BMS is only responsible for the charge algorithm so why does it create warnings for High voltage?


Vangelis Beligiannis asked
micmak answered ·

5 Answers

Two 250/100 MPPT controllers in parallel - One staying dormant....

Hi there,

just installed a 10kWp PV system (6 parallel strings of 4 PV modules in series) feeding into 2 MPPT controllers (250/100), which again feeds a BYD LVL battery bank (2 parallel modules of 15.4 kWh each):


After firing up the system, only one of the 2 MPPT controllers is feeding into the batteries (solid blue BULK light on). The other one remains in an OFF state (blue BULK light blinking slowly), also as shown by the VictronConnect app:



I'm at a loss why this is happening.

The OFF MPPT controller is correctly connected to the battery bank and PV arrays and breakers / isolators are switch ON.

I have also made a "Smart Network" connection between the 2 controllers through the VictronConnect app, hoping this would have the 2 controllers talk to each other, but it didn't make any difference. One of them remains inactive.

I'm wondering whether the BYD BMU has anything to do with this, since that is the unit in overall control of the system.

Hoping anyone of you can shed some light on this. Thanks very much in advance! :-)

kiwisolarfuture asked
seb71 edited ·

2 Answers

ESS-managed batteries on 230V split single phases

Hi all, here in the UK I’d like to buy an ESS system to provide PV battery storage on our 2 x 230V/100A split-single phase grid supply. I’m thinking of dual MultiPlus-II 48/10000/140-100 units plus Cerbo GX.

My question is, can each MultiPlus-II be connected to the same battery array? It would be great to be able to significantly reduce the problem of frequently exporting on one phase (with no financial gain) whilst importing on the other (at large financial cost!).

For the batteries I’m looking at Pylontech or BYD but would welcome any opinions and suggestions especially if there’s a specific type of battery which could be connected to both phases at the same time and still be managed by the MultiPlus units. Our PV is 26 kWp with grid usage at about 50 MW/year.

If anyone can help with my battery question or offer any other comments, please let me know!

I also need to find a distributor/tech support.

Many thanks,


Glenn Garrett asked
Alexandra answered ·

1 Answer

set the BYD battery to sleep mode


I have a solar photovoltaic system for self-consumption with a solar charger, a Victron Multiplus II inverter and a BYD battery. At the moment, I don't want the battery to work to satisfy the consumption, i.e. I only want to inject energy from the solar field. Could I achieve this from the Victron VRM Portal?

Thank you very much.

fernando-barrena-barrero asked

0 Answers

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