Originally Posted by Bill Glover
Aha ... looks like there should be a diode I can 'recycle' on the PCB inside the car charger (which I am never going to use)
Edit - adding that diode drops the voltage at the battery pads from 5.1V to 4.6V when the camera is recording, which will definitely help. I'm only going to be making short recordings ... 5-6 mins at most ... so that will probably do. I put the diode in the -ve lead as there was more room ... presumably doesn't make any difference (so long as it's the right way round
Find a second one and it'll be perfect! 4.6V is certainly much safer than 5.1V, so most probably you'll be OK. Playing with resistors wouldn't be such a good idea since they'd have to be in parallel and you would loose more power in the way of heat. I'm glad you found a spare diode, much safer that way. Putting it in the negative lead doesn't matter here.