Neither the BMS nor the batteries are from the NG series.
The termination resistors for the VE.Can bus are set correctly (not shown in the diagram).
The ATC and ATD connections on the BMS are currently not connected. The bridges on the REM connections are installed on both the inverter and the BMS (not shown in the diagram). At the beginning of commissioning, the firmware of some components was updated where necessary.
The power-up sequence was as follows:
Switch on the inverter
Switch on the main battery switch
Connect the PV modules to the inverter (switch on the isolator)
Activate the Smart BMS via ConnectApp (Bluetooth)
When the system was activated, communication between the components worked from the outset. The inverter, BMS and distributors can be accessed via the GX device and the VictronConnect app. All components are accessible through the VRM portal. The inverter detects the GX device and switches the charge controller to “External control”. The inverter starts up and the output has 230V~. The fuses for unused connections/fuses on the distributors were disabled.
There is a serious problem: the inverter does not charge the battery through the BMS.
The BMS status shows:
Charging allowed: No
Discharging allowed: Yes
At the time of my last attempt, the SoC was approximately 50%, so a battery that was already fully charged can be ruled out as the cause. I spent a long time searching unsuccessfully through the ConnectApp and Ekrano menus to see whether there was a setting to enable battery charging. DVCC was automatically forced on. In the Ekrano’s “Settings” menu, under Settings->Devices->Lynx Smart BMS->Parameters, the parameter “Charge current limit (CCL)” is shown as 0.0A. According to my research online, CCL is a parameter used to protect a fully charged battery. It therefore should not be the reason why the battery is not being charged. The value cannot be changed either.
In a further test, I connected the battery directly to the inverter (via the main battery switch and a fuse) and removed the BMS from the VE.Can bus. The inverter was then connected only to the Ekrano via VE.Can. After removing BMS control for the inverter by resetting it in ConnectApp, the system worked perfectly. The inverter charges the battery using its own algorithms. It would probably be possible to operate the system this way. However, you would then not have monitoring of the individual battery cells. I would very much prefer not to give up this function provided by the Smart BMS. The investment in the Smart BMS and the distributors would also have been wasted.
Could someone from the community perhaps tell me what I need to do differently to make the system fully operational with the BMS/distributors, so that the battery is charged as well? I would be very grateful for any advice that might help.
Welcome and thank you for writing a comprehensive report for question.
From the manual of the bms, could it be that? You state that the batteries were 50% charged, how long since last charge and balancing? What does victronconnect say about the batteries?:
Also, i would normally close battery isolator, and start the bms before any other item like inverter in startup stage, but then i dont have that model inverter
If the batteries are new there is a protocol to fully charge batteries individually prior to connecting them together and ensuring balancing is achieved. Refer to manual of your battery
That won’t be the cause, but why do you switch on from “back to front”?
The batteries should be first, so that everything is supplied with power and can start up.
Then you can check in the GX whether all the components that have been switched on have been detected correctly and make any initial settings if necessary.
Then comes the inverter, and finally the PV and AC circuits.
NO!
If the BMS displays “Charging disabled”, there will be a reason for it, and you shouldn’t simply work around it.
The batteries also have Bluetooth—what is being displayed there in VictronConnect?
Thanks to Matthias and mokosh for the quick initial advice!
As some background, I would also like to add that I put the system into operation about five weeks ago. There were other issues to deal with as well, so it is only now that I am bringing this problem to the forum. Since the battery was not charged via the BMS from the outset, I removed the BMS from the system at an early stage and connected the battery directly to the inverter. The inverter’s charge controller works perfectly. Whenever I check, the ConnectApp shows me the “Balanced State” for the batteries. Home Assistant tracks the battery voltage and other parameters. Everything looks good and plausible. What I am missing with the inverter’s charge controller is monitoring of the individual cells.
Following your new advice, I operated the system with the BMS for a little over 24 hours from yesterday to today. The start-up sequence:
Battery → BMS → Inverter → PV modules → AC loads
In the ConnectApp settings for the BMS, there is a parameter called “Charge state threshold” (default: 70%). When the threshold is undershot, a new charging cycle is supposed to start. I had overlooked this so far and wanted to test this functionality. During operation, the AC loads were supplied either from the battery or by the PV modules. Around midday today, the threshold was undershot, but no new charging cycle was started. Disappointing. I then removed the BMS from the system again. During the afternoon, the inverter’s charge controller charged the battery again. I had also suspected that the system might need more time. In previous attempts, I had always removed the BMS after a shorter period. However, I do not want to wait until the battery is completely discharged.
I am now running out of ideas. The system is not producing any error messages that would be helpful, but there is a suspicion that this inverter and the Smart BMS may not be compatible. In the inverter manual, section 2.6, it says: “Use smallBMS for the RS with Victron lithium batteries.” On the other hand, I seem to remember seeing this inverter on a Smart BMS compatibility list.
2: Please provide more details about the wiring of your setup including the fuses and cables used. You would not be the first person caught out by a funny voltage drop somewhere, especially if “budget” fuses or circuit breakers have been used. Share a diagram of the network showing cable lengths and x sections
3: SHow your fuse positions and ratings and type, e.g. Class-t 200A
4: Measure the voltage at the inverter battery terminals when the inverter is off and the Battery and BMS is on.
5: Make sure all cables are tightened according to specificationusing a torque wrench.
6: Share screenshots of the victron connect display for each battery and its cells
7: Some photos of the installation will also help us orientate ourselves
8: Share screenshots of the battery selection and charge settings in the Inverter
I know its back to basiscs stuff but thats how diagnostics is done…
Good luck and let us know so we can help you with a “4 eyes check”.
Alex
I concur that your batteries are compatible with your BMS as per this link:
I had completed my reply in full, i.e. with lots of screenshots and images. When I wanted to send the message, I was informed that, as a “new user”, I was only allowed to upload 5 embedded media items. So I suppose I’ll have to split my reply across several posts I ask for your understanding and a little patience.
Here is the first batch of requested information:
1: Screenshots of the inverter (ConnectApp)
The battery switch is an original Victron product. The temperature sensor is mounted on the negative terminal in accordance with the regulations. V-Sense leads are installed. Both leads are protected by 1A fuses (You never know… ).
You don’t need any of that.
The main switch is integrated into the BMS; the BMS provides the inverter with the voltage readings via the GX, and the batteries or the BMS also handle temperature monitoring.
Could you also take some screenshots from VictronConnect showing the BMS?
I suppose I may no longer need the temperature sensor once the BMS is fully doing its job. The battery main switch is indispensable for me, as it allows me to safely disconnect the battery during maintenance, troubleshooting, modifications, etc., without having to unscrew things first.
Here are the screenshots from the ConnectApp for the BMS. I hope these are the right screenshots, as it will be two days before I can take new ones.
Simply unplug the 10-pin connector at the bottom of the BMS, or replace the jumper with a switch.
The BMS will then switch off and open the main contactor internally.
And the overview page from the BMS?
Also work through the troubleshooting section in the manual, especially from section 9.4 onwards.
Out of curiosity, I disconnected one of the BMS cables. The BMS status LED then indicated a communication error. Once the connection was restored, the status LED on the BMS was permanently green again.
Following Matthias’ recommendation, I looked at chapter “9.4. BMS problems” in the BMS manual again. In my opinion, the causes listed there for the charger switching off do not apply to my problem, because my batteries are always balanced.
I ask for your understanding and a little patience.
).
