Anyone has any instruction on how to set the Dongle to a Static IP?
How to set Static IP on Dongle?
If you go to STA settings page, there is a LAN connection type drop down from DHCP to static

dorosde it's probably best that you do this from your router rather than the dongle - as other devices on your network will be DHCP if your dongle disconnects and something takes over its IP it could cause an issue when reconnecting
simont When done that the other day I thought it worked, but then realised that I couldn't only access the Inverter in Local mode only. At Subnet mask I entered: 255.255.255.0 and at Default gateway: 10.10.100.254. I don't know if the problem (of only accessing Local mode) was because of the value set on Subnet mask and Default Gateway. Reverted to DHCP after faced these.
Cdent I will give it a go through the Router then
dorosde just to rephrase: "I could only access in Local Mode"
Cdent So I entered the setting of my router in Virgin Media, but is not very straight forward on how to set the dongle to static IP.

Attached two screenshot which I believe are relevant with this. Do I select the HF-A21(the dongle) and add it in the Reserved IP Addresses then? Is the reserved IP addresses list "Static IPs"?

dorosde I would say so, though I've got an Asus router which seems to be a little more user friendly. I think if you click the add rule button then apply changes that would do the job
Cdent That did the job then! It's been moved to the Reserved List of IPs now. Away and Local work just fine!
Well done, you found out how to do it.
The procedure is not easy to explain, but I tried to document it.
https://givenergymonitor.wixsite.com/tutorials/connecting
Now if there was a smart way to access the Inverter in "Local" mode whilst not being connected on the Home Wifi that would have been brilliant. But my IT knowledge is limited to be able to know or attempt of doing something like that :-) !

dorosde VPN is your best shot here, I use home assistant to control everything as though I'm local so that's another option.
Cdent Yeah, I 've been doing some reading of Rasberry Pie and Home Assistant etc...I still haven't pulled the trigger and go and buy one as I feel is too much to learn to be able to get it working...knowing me eventually I will pull the trigger and give it a go...

dorosde start off small and work your way up - I got mine because I was fed up of having multiple apps for all the different things - GE, LightwaveRF, Tapo, Govee, etc. and wanted something to be able to monitor/control in one place. If you have loads of smart home tech it's worth it, if it's just for GE maybe not (unless you look into the automation stuff like PredBat!).
Only problem then is where do I stop - now I'm buying things to connect to it just because I can!
Cdent Well I have the Hive, CCTV System, Givenergy System, so maybe I can justify it :-)!

dorosde definitely! If a RPi seems a little much, see if you can pick up a cheap thin client off ebay, that's what I did, stuck a larger SSD in and it's been solid. Only cost £30 plus £6 for the SSD