Searching for "EL cold light" on eBay is believed to be fruitful. The result of my search is that these products are basically from China and I don't know if they are sold locally. It should also be noted that the shape of the lamp, about 3mm in diameter, requires the purchase of lights and drivers to work, the minimum operating voltage is 3V, low voltage working brightness will be reduced, so the replacement of power interface can be directly connected to the battery box. I'll buy some and do some tests, hoping to succeed.
@brunojj1 At the same time, thank you for your efforts and persistence, although the RC version of the instructions have not been completed, you do not need to apologize, we all know that you did not give up, thank you again, and wish you a Merry Christmas.