Fronius 5000VA Inverter AC Coupled with 4.5kW of panels
Victron MPPT 48V 85A with 6.1kW of 510W Aiko panels connected
I switched my Multiplus to Invert only mode with MQTT and ran like this over night, in the morning I had about 15% battery left. The MPPT started charging the battery at about 7:30am and continued to charge the batteries throughout the morning until 10:38 (to 42%) when the Multiplus stop supplying power to the house and shutdown into low voltage. I have no idea why this would have happened as the batteries are delivering 52.48V currently.
I never had this behaviour while running for month Grid connected.
I ran checks on the batteries by connecting to the BMU and read all the BMS values, all cells are fine, and are in balance, there does not seem to be any issue with the batteries.
I have tried the system restart procedures for low voltage.
I have run a multimeter over the Victron Lynx bus bar which reads the same voltage as the Batteries voltage 52.48V
I do notice in VRM that the Multiplus voltage is swinging wildly from 40 odd volts to 54 volts.
I did an Inverter firmware update which does have an fix for Australian Grid Code V560
Does anyone have any ideas how to recover from this state?
The Cables are all fine, it turned out that it blew a fuse after I had tested the fuses. I have replaced the fuse, all fuses are now fine and it has cleared the low volltage alarm
Below is what happened and I have no idea why the grid lost error would trip the inverter to shutdown to this state when it was running inverter only. I had to switch the inverter to charge only in the multiplus manual switch to get power.
Now when trying to join the Grid, I am getting VE.Bus Error: VE.Bus Error 11: Relay test fault with the float light solid orange and the Bulk flashing orange alternatively to the inverter on light flashing green. Using the same Grid code and nothing there had changed. When I installed the new firmware, I loaded back the previously set parameters and sent them to the Multiplus, got an error about updated ESS assistant, so I deleted the old and added the new one with the same parameters as before.
I am attaching a service log, and the Ve Configure parameters, which include the new ESS Assistant running.
A system before it connects to grid saturates the transformer to power assist on connect. So it will draw more from the battery shortly before. If the fuse is not rated for the conditions then it will blow.
The error 11 is a wiring error related to neutral - earth.
Or a voltage between the two. Either way a wiring problem. Not necessarily in the installation but definitely something connected to it. Things do change in wiring.
There is a details step by step way to diagnose it in the link above.
Thank you again, I started to take a look through this article, but the Australian grid code part confuses me. I will get my Sparky to take a look.
Don you know much about the Australian requirement “it may be mandatory to make an external connection between Neutral-in and Neutral-out” And where does this need to take place, is it at the earth bus bar or does it have to be at the inverter? My system didn’t previously have this and was running the grid code shown in this article that it is not externally joined.
The fuses and all cables should all be big enough, the system has been powered on numerous times without issues after firmware updates and testing. I think the hotwater turned on with the rest of the house which blew the battery fuse, never had that happen before, this is being changed from 125A to 200A, because my new solar MPPT, ac coupled inverter and grid if all sending power to the battery it is now too close to the 125A.
I am reading from this you do not have to do anything (wiring) just select a neutral bypass grid code, and the Multiplus changes internally the way this works?
If they are bonded externally and the code is used it changes things.
There is an earth neutral bond made in the inverter on all other grid codes when the inverter switches to inverting.
Most grid codes state the bind must be made at source, so if that is the main incomjng DB then it is there, if grid goes out then the new source is the inverter, it is made there.
