I installed a Victron for a customer about 3–4 months ago, and it was working fine until yesterday, when he managed to overload the system… Three MultiPlus-II 48/5000/70-50 three-phase units are installed.
I’m attaching photo documentation and a video where I turn on the MultiPlus units, and then they throw a low battery voltage error; I turn them off, unplug the communication cable from the Cerbo, and the MultiPlus units start up normally with no issues. As soon as I plug the cable back in, after a moment they throw a low voltage error and a synchronization error…
Sorry for the video quality, but the full-quality version is 300 MB.
You’re pulling 6000W from a 4000W inverter. Ouch.
What battery is this?
What are the inverter/charger settings?
Sounds like you have hit configured cutoffs, or the battery is unhappy - can you provide the BMS limits advanced widget chart?
I don’t quite understand the connection—the battery seems to have a problem… it isn’t reporting any alarms, and the MPPT chargers have charged it to 100%.
I’m trying to figure out why the Multiplus is reporting low voltage even though the voltage isn’t actually low, and why the Multiplus units work fine without being connected to the CERB.
Please carefully read my post. It requested additional information. Low voltage errors can come from the battery or the inverter, hence the request for more detail.
There is not enough detail here to help, so we can either guess or you can help us to help you.
Use the software switch on the gx interface instead. That way they switch as a group and one cohesive system.
For the low battery voltage i would hazard a guess and say it is dc ripple.
Check for that.
Check your battery terminal voltage for each inverter and terminal torque
(And also all the connections in between.)
The low battery warning is active when the battery voltage drops below the dynamic cut-off level plus the restart offset, which defaults to 1.2 Volt for a 48V system. Just like the cut-off voltage, the warning voltage level is also dynamic.
There is no hysteresis: the warning will disappear when the voltage rises again.
During this warning, also called a pre-alarm, the red LED on the Multi will blink, and optionally the GX device will show a notification. For most ESS systems its recommended to disable that notification on the GX device. See FAQ Q5.
The related parameters on the inverter tab, ie. the DC input- low shut-down, restart and pre-alarm levels do not apply. They are ignored when the ESS Assistant is installed.
