Problems after firmware update v3.79 – no BMS or Low Battery alarm

DIY
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1

Hi,

Yesterday I carried out a firmware update of my MultiPlus II GX 48/3000 to v3.79, and since then I have been experiencing considerable problems getting the system running again. It had previously been working perfectly for 1.5 years.

MultiPlus-II 48/3000/35-32: I keep getting the error message “VE.Bus System - [275] Low Battery: Alarm”.
SmartSolar Charger MPPT 150/35: My SmartSolarCharger MPPT 150/35 is running firmware v1.74.
Pytes E-Box 48100R battery: connected to the MultiPlus via CAN
EM540 energy meter: connected to the MPII via an RS485-to-USB adapter

Immediately after the firmware update, it initially said that no BMS was present, but I was able to temporarily resolve this by unplugging and reconnecting the CAN connector. Now, however, I am getting the Low Battery warning even though the battery is at 40% SoC. Occasionally, the MPII’s relays click repeatedly, and then the warning appears again. So far, I have tried the following:

  • I updated/uploaded the configuration using VE Configure 3, including the ESS update, and all voltages are set according to the manufacturer’s specifications for my Pytes 48100R battery. https://www.panda-solar.de/images/Datenbl…Veconfigure.pdf
  • I updated the firmware for the “modification check” (Settings->General->Support status (modification check)) because the text was displayed in yellow…but it made no difference.
  • I restarted the MP II, but this did not solve the problem.
  • I shut down the entire system, switched off and disconnected the battery supply, completely powered everything down and then started it up again. This did not solve the problem either. What is also strange is that the MPII does not even charge my battery from the mains when it thinks that the SoC is too low. It used to do that.
  • It is also strange that the battery’s SoC supposedly fluctuates between 40% and 100%…I don’t understand it.
  • The sun is shining, but 0 W is being received, neither by the inverter nor by the MPPT SolarCharger.

I am really at my wit’s end and have now been struggling with this problem for 4 hours without making any progress. Could someone please help me?:sleepy_face:

A few more screenshots for reference:

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2

It’s sorted now: it was an undersized 30A fuse between the battery and the Lynx. The inrush current obviously put so much strain on the fuse that it blew. It was barely noticeable visually; you only see it once you unscrew it, so I didn’t realise that was the problem at first. It was only after I took the time to go through a start-up procedure and take measurements with a multimeter that I noticed the faulty fuse. :melting_face:

I’m relieved now and will order a slightly higher-rated fuse. :sweat_smile: