chelin

WhatsApp.. I will look for my backup. Is your fan also , constantly running ? 

I use a Greenrich UP5000 battery with solar on the SunSynk 5.5Kva inverter.
Very good battery, no issues at all. Installed in August 2022.
"2C" discharge means that the unit can produce "twice its rated current over time". 
The Greenwich is a 5Kwh Battery. At 1C, it could produce 5000w for 1 hour, or 500w for 10 hours, ect..
At 2C, the battery can produce 7500w (maximum rated) for 30min.
Also, keep in mind that your inverter will need to handle 7500w for that to make any realistic impact. Checking the specs of your Growat inverter, it can only handle 7500w for 5s before overload, so no need to worry about the battery.

I’ll try this during the weekend.There are some settings that I’m testing with @RudShep

It changes everyday. 
 
storage + date in yyyymmdd format. - so today will be storage20201011

Hi Conrad. DON'T use AGM... the voltages are wrong for Lithium.
As zsde said, use USE mode and set the parameters to what the battery manual says. Post a page or the entire manual here and I can try and help.
You can run on USEr defined mode but it is certainly better to get the inverter and battery to communicate with each other via the comms cable. Trouble is there are over 15 "profiles" on the Growatt and two ports - CAN and RS485 so it is hard to find a combination that works.
I am busy setting up a bit of a database of inverter and battery combinations and settings and will be happy to go through the pain to get yours working with you to get some data for the register.
Rudie