(05 Apr 2016, 7:30 pm)Dan wrote I'm no sparky, but I'd imagine more wiring would be required, yep.
A cheaper alternative is to fit USB power sockets in between seats, or to the back of seats. Arriva have started to fit them to the backs of seats on their MAX refurbs, but I understand these aren't half as effective as the normal power sockets (in terms of charging).
Nah, they're not. I tried them on both the Transdev 36 and the CityZap last week, and it must have only charged my phone by 2%-3% at the most. That is with power saving enabled, and me barely using the device.
I appreciate that the S6 has quite a large battery for a mobile device, but on the other hand I know I'd get a decent charge out of an on board AC socket.