I think reverse polarity (your +ive Earth motor) would Fritz the camera.Hi all,
Thanks for all the replies. As I guess no simple solution. I will look into adding a fused fused inline power socket. I should also have pointed out that I have both positive and negative earth cars. Would the socket also work with the positive earth car?
Phil
A GoPro with onboard battery would last a while, and a PowerBank would extend that in the +ive Earth car - maybe that's the best compromise?