Low battery alarms despite a battery voltage of 26 volts (Phoenix 24V - 3000W inverter).
Please post details about your setup — we can’t see it for ourselves!
Hello, and thank you for replying to my post.
The device reporting the “bat low” fault is an inverter 24/3000 230V VE.Bus.
It’s a backup unit (which was used to replace a MultiPlus 2 while the latter was away for servicing to check the residual ripple in the AC signal).
It worked perfectly for almost two months, then one night it suddenly stopped with the “low bat” indication, accompanied by a fault notification email, as at the time I was using a gerbo-gx connected to my router via Wi-Fi.
I cleared the fault, and the device worked fine during the day, then went into fault again at night (when there was no load from the MPPT).
It’s worth noting that the battery voltage at night did not fall to the critical threshold (pre-alarm setting: 23.50V and low-voltage cut-off: 23.20V); the voltage overnight was 25 volts (battery charge level in the morning: 35%).
The installation consisted of 8 LiFePO4 cells, 200Ah, a Mastervolt 150A BMS and a NEEY 4A cell balancer, as well as a Victron MPPT 150/60 and, of course, all the required DC and AC protection devices.
As my MultiPlus 2 (24/3000) had returned from servicing, I installed it in place of the inverter 24/3000, but without connecting it to the gerbo-gx.
The MultiPlus 2 has never gone into fault.
Now I’ve set out to test the inverter 24/3000 again, connecting it directly (without a BMS, just with an isolator and a fuse on the DC line, and with no AC loads) to another set of charged batteries, consisting of 8 K2 Énergie lithium-ion cells, 89Ah, model K2B3V90E, voltage 26.67 volts.
The red “low-bat” LED comes on immediately, and as a result there is no voltage at the AC output.
At this point, I think there are two possibilities: either a software fault (crash) or a hardware fault caused by a defective component in the electronics (voltage comparator)?
The first possibility might be something we can resolve with help from the Victron community; the second would require sending the equipment to a brand representative.
While I wait for your replies, I’ll connect my PC to the device via the MK3-USB interface and see if I can restore the factory settings.
Many thanks in advance for your help.
Kind regards.
Claude4
Was your MP reprogrammed after it came back from servicing (and presumably received an update)? Was it also properly installed in the system?
If not, you may now have a damaged battery system as a result.
There is no risk of interference between the batteries, the BMS and the NEEY cell balancer, and the Victron system… They don’t communicate with the Cerbo GX, the MPPT or the Victron inverter in any way… The batteries are just batteries (with no built-in BMS); the BMS is programmed using simple microswitches, and the cell balancer is programmed via the NEEY manufacturer’s Android app, but it doesn’t exchange any data with the Victron system.
I’ll look into the inverter settings and see if I can reset it to factory settings.
The lack of communication could be the main problem, along with the MP being reset to factory settings after servicing (and therefore the lead setting).