question

Yes that will work, can't really see why you would do that. Maybe I misunderstand. Are you running you inverter from batteries to get 220v then transforming down to 12v to run the ccgx . ??

in fact,i need ton install the color in my house instead of my other batteries local.The distance is 20meter , i have a good quality ethernet cable for linking to the Multi and a transformer220v/12v is close to me to get the voltage to the color. That is why i wonder if i can use it , if not i need extend the stock wires to the batteries to 20 meters

That will work fine, keep in mind that the transformer power supply must be DC 8 to 70 volts do anywhere in that range will work DC only

Hi Ram. This isn't a direct answer to your question, but I'd encourage you to consider using that ethernet cable just for a remote and totally functional link to your CCGX, which you could then leave next to the Multi (and other kit you may decide to add in). Laptop/Pad/whatever.