I currently have a 10Kwh Freedomwon battery. I want to add an extra battery.

1. Is it a must that I use the same installer I used for the setup or I can shop around?

2. Is it a must that the installer must have "sharing" in my system?

   1. Can I remove the installer from the sharing?

   2. Pros and cons for this.

These are very important questions that you are asking, and have a much wider "audience application" than just adding a second battery - perhaps you should change the title of this thread...

In my mind, you have the final say in what you want to buy, and who you want to work on your system - unfortunately most of the manufacturers, wholesalers, retailers and installers are running a type of protection racket (the "solar mafia") in this industry. The manufacturers & wholesalers are protecting their loyal installers, and threaten to not honor their guarantee if someone other than the original installer work on the system. I've had such a run-in with a wholesaler who was a Sunsynk agent at the time, that insisted I use the original installer when I had a problem with one of the batteries, else they would not repair the battery under warranty...

I did insist, before accepting the installers quotation, that I will be the sole controller of my system, and that he had to transfer the "owner" in the app to me. I think that you are fully entitled to insist that the installer be removed from sharing your system. The only "con" in this regard is that the installer cannot remotely visit your system to check it if it develops a problem, and you are thus forced to really understand the system and all the settings.

Apologies to the decent, professional installers who are not part of this mafia (and there are many of them on this Forum) - no offense meant to you.