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Dear All ,
I have a peculiar issue that the inverter even with hard coded lower voltage cut-off at 18.7V
and alarm at 20V ( Via VictronConnect and latest FW )
and still the inverter cuts off at 24 V exactly.
The current shunt and MPPT controller reports the same voltage during the shutdown
I hope someone could provide some light ?
Thank you
The Harvester
What voltage is shown in the inverter via VictronConnect?
What load is running at that moment?
Can you measure the voltage at the battery terminals of the inverter?
What wire gauge is used from the inverter to the battery and how long are the wires?
My guess is a high voltage drop due to a loose connection somewhere or to thin/to long wires.
Well the shutdown happens at 5,6am in the morning I am not awake to go look.( I will check if the VRM keeps track Voltage from the Inverter )
The running load is a fridge and a NAS ( 95W on compressor run and 20W standby PSU all in all 115W the loads are a joke and I have a huge Inverter )
I can't because the system is on a remote location that At the moment I do not have access to.
Wire gauge used as per the manual 50mm^2 at less than a meter, 1.5M tops(if I don't remember correctly 1.5M is top length I think) from the battery.
Loss connections are impossible because everything was torqued down to spec as per the manual and inline fuses are sized as per the specifications of the inverter.
But other times of the day I had a look on the voltage from the inverter and also from the shunt and the voltage drop was almost negligible.
I will look again , but from 24V from the battery have 18.7 V at the inverter meaning I have a 5.3V voltage drop ? I find it very improbable/ impossible with proper crimped cables and proper cable used... as per the recommendations of the manual.
Thank you in advance for your input
The Harvester
Dear Sir ,
I just checked now
and with a 27VA load the voltage shown is 27.13V from the Inverter ( though the VictronConnect app )
the shunt( though VRM) shows 27.16V that's 0.03V voltage drop.
When the Fridge will start up I will re-check the voltage.
But I am sure its going to be fine I made the install on the proper specifications.
Thank you in advance
The Harvester
Dear @Matthias Lange - DE
Now the Inverter is under "Full" load : (138VA)
and I see on the Current shunt battery voltage 27.17V
and on the inverter battery voltage 27.11V
so 0.06V voltage drop from Shunt to inverter.
I consider this normal.
Any other insides ?
Thank you in advance
The Harvester
what kind of BMS are you using?
because, the detected values of the BMS will always count in the end (LTP).
if you are using a BMS which is configured seperately - by software or DIPswitch etc... - those hard coded parameters will overwrite any fixed parameter which you have set in the ColorControl / (even in the inverter itself) or whatever you are using for display / control.
example: assuming you have set a value for charging up to 27.6V in your inverter but you have set the BMS to start balancing at 3.6V for each cell, your MAX charge voltage will rise up to 28.8V before the system will enter absorption mode - 3.6V x 8 (in a 8S system).
the same will happen with battery low voltage: if you have set a parameter in the BMS to cut-off the batteries at 2.8V or lower, the system will continue to discharge until 22.4V
in your case the parameters might be set to around 3V / cell - that at least would explain the 24V cut-off.
Thank you for your input.
No there is no BMS as I am running a 2 x 12V AGM batteries 150AH to make 24V system.
Thank you though.
Thank you in advance
The harvester
Dear All
I woke up today at around 5am the inverter was off on alarm. I started it and voltage didn't drop lower than 24v from the victronconnet and then re-alarmed and stopped.
So there is something wrong with the inverter FW. (its on the latest version) i will try to rollback 1 version.
Please advice how to move forward?
Thanks
The Harvester
A small hair dryer or kettle? Something to have 500-1000W load on the inverter?
It's hard to troubleshoot if it only happens in the middle of the night.
It can also be a problem with your batteries.
During the day the MPPT helps to maintain the batteries and during the night the batteries are discharged slowly.
At some point the inrush current of the fridge compressor drops the voltage below 24V.
