Did the firmware upgrade.

It seems the 18A MPPT limitation is gone.
I had today 5800W from 6kwp compared with version.... 05 7.01 where the MPPT could not produce more tham 5000W from my PV setup.

Here is a good guide
You need the usb-serial drivers (the same from the cd with PVKeeper), the ISPTool v4.20 or 4.30 and the bin files.
If you wish to do MPPT fw-upgrade, load F030 file first (7-10min) and after inverter restart, load the inverter file F2809 (8-11min)

https://www.elleyhillpower.co.za/pages/growatt-spf5000es-firmware-upgrade