Windows graphical, latest experimental build (04b9ef8)
Similar issue - when I apply a UPS conversion kit to a mp3 player (running either a personal UPS bionic or a standard UPS) and switch it on, it stays “on”, but does not play the music (no ‘music messages’ in the event list) and seems not to have ceased providing a morale bonus (slowly decreasing in regards to when I had been playing the battery-powered player).
If I apply the UPS kit to a flashlight, it shows it to have one charge -> “flashlight (off) (1)” regardless of how long I let it sit in my inventory with an active UPS. Sure, it works, but the light range is severely limited (half ?) in respect to what battery-powered flashlights provide.