Hello forum members!
I have converted my Victron system consisting of 3x Multiplus II 48/3000, 3 MPPT 250/85, Victron Venus OS 3.5 on Raspi 4, from AGM battery (48V, 610Ah) to LiFePo battery (16 Cell, 280Ah) and JKBMS JK-B2A20S20P.
I did some research beforehand, e.g. Andi’s Off Grid Garage and his videos and found even more and read up on the topic. I then adopted the settings for the BMS from Andi (My Settings - the Off-Grid-Garage) and converted the Victron system to LiFePo with VEConfig, installed SerialBattery on the Raspi and started everything again.
The first aha moment was that the battery was charged briefly on the Victron GUI and then no longer. After some trial and error, I deactivated discharging in the JKBMS app and now the battery is charging, but intermittently, i.e. briefly up to the maximum charging current or what the solar panels (16.4 KWp distributed in 3 directions) can provide and then nothing more. After a few seconds, it goes back to max. current and then back down to zero.
Is this the so-called initial charging up to the OVP (Cell Overvoltage Protection Voltage) to “get to know” the battery pack or is something wrong?
I haven’t observed anything like that with the AGM batteries, but there was no BMS involved either, everything was controlled by Venus OS.
I would be grateful for tips.
Happy holidays from Austria
Hast du auch die Drehschalter an den MPPTs auf 7 gestellt?
Das sieht mir auf wie ein Abschalten durch das JK, Cell Overvoltage Protection. Ein Kennenlernen gibt´s da nicht, nur Schaltlogik. Was zeigt den das JK in der App an? Die Ladeleistung ist zu hoch für einen Akku, hast du 0815 Zellen oder matched cells? Wie hoch ist denn der Zellspannungsunterschied beim Abschalten? Hast du unter DVCC die Ladeschlußspannung begrenzt (55,2V). Ausserdem gibt´s bestimmt noch ne Handvoll Warnings die du uns noch nicht erzählt hast. Blas dir das Pack nicht hoch!!!
Danke für die schnelle Antwort,
mir ist der Schreck ganz schön eingeschossen. An die Drehschalter hab ich nicht mehr gedacht, ich war der Meinung dass alles (auch die Ladekennlinie) durch die Konfiguration über VEConfig gesteuert wird. Noch ist der Ertrag der PV Anlage überschaubar durch den tiefen Sonnenstand und die Aufteilung auf drei Felder, je eines mit 16 Panels nach Osten und Westen und eines mit 8 Feldern nach Süden. Max. Ladeleistung war ~ 30 A und da Paket ist zu 90% geladen. Sind EVE 280 A Zellen vom LiFePo Shop.
did you turn DVCC on? can you share here some of your settings ? If you wat to do like Andi, you must:
- calibrate voltage of the battery
- turn DVCC on
- make sure your MPPT controllers are in external control
can you share pictures of your installation and some of your settings to better help you? it does sound like OVP. definitely not normal behaviour. (i work with JK all the time)
DVCC is on, I had a well working system with AGM batteries the last 2 years running. I changed from AGM to LiFePo, added a JKBMS (the AGM had only balancer, BMS was done by Victron), changed the battery type in victron VEConfigure, installed DBUSserialbattery, after advice by saschaho switched the MPPT from 2 to 7.
I am frustrated, the battery has 100% and the three Multiplus II do not switch to inverter mode.
My configuration:
These settings were deployed to all three Multiplus.
The JKBMS is configured with LiFePo settings from Andi.
If more information needed please specify which.
Thanks
They do not switch to inverter mode because you have put them in pass through mode…
Are you not using your multiplus to charge? You have disabled your multiplus charger. What is exactly the setup? I imagine a 3 phase grid tied system optimized for battery life?
By the way, from Victron:
10.4. Q4: Why is the VE.Bus state in pass-through?
In ESS, the conditions for the VE.Bus system to be in pass-through (ve.bus state: passthru) are:
- When the GX device is no longer receiving data from the grid meter. Note that this is only for systems that are configured to have an external grid meter. See the Settings → ESS → Control without grid-meter setting.
- Systems with a canbus-connected lithium system: when the GX device is no longer receiving information from the battery, via the CAN-bus.
- When charging the battery is not allowed (BMS max charge current = 0A, or max charge power = 0W) and there is excess PV power.
- When discharge is not allowed -and- loads on AC-Out force the Multi/Quattro to exceed the AC input current limit. Reasons for not allowing discharge: BMS blocks discharge (DCL=0), or battery SoC level is below the ‘minimum SOC’ setting in ESS, when SoC is at least 3% above the set level, discharge is allowed again.
- A grid code is in use that requires the enabling of battery discharging by aux-inputs. Check the used grid-code in VEConfigure and compare with the electrical signals provided to the Inverter/charger in its AUX inputs.
- The Loss of Mains detection (LOM) causes issues, often in combination with a high impedance connectivity to the utility. For details see VEConfigure: grid codes & loss of mains detection.
Did you put a CAN terminator on the side of the Cerbo? Do you have good comms between cerbo and battery? Do you see cell voltages when you click on details of the battery CAN?
Is the reason why it is in passthrough and won’t invert. (Reason 4 in @Elb answer)
You will have to share your jk settings. It is possible that we may see something you overlooked in settings.
it might be badly topbalanced and thus going immediately into overcharge protection… But its difficult to say from here.
What you can do is enable discharging but disable charging, and let us know what happens? If you set your charge voltage to 55.2V, a properly top-balanced pack will be fine and allow you to discharge it…
I think I found the reason: Grid metering was set to external meter and in my system external grid meter is not needed because the Multiplus is interposed between the grid and the consumer. So without information about the currents go in or out no inverting is possible. At the moment it is discharging with ~50A (heat pump is working)
Not the complete load is delivered by the inverters, the DCL is not high enought now …
Thanks for the support!
Great news! So good to see it work!
Make sure to properly top balance that pack though!
