Peter

Your best bet would be to use a power distribution board such as the ACTion P92 or P112. The battery is connected directly to the two input terminals and the board provides for a number of fused output terminals at the same voltage as the battery from which you can run auxilliary functions.
To switch such functions from the transmitter you need an approriately-rated RC switch. This is connected to a spare receiver channel.
You can find any number of circuits involving DBs and switches on this website https://action-electronics.co.uk/wd.html
and ACTion units can be bought on-line here **LINK**

Dave M

Edited By Dave Milbourn on 05/12/2018 09:23:51

Peter

There are a couple of articles here about RC switches – just scroll down to the title and click on it. **LINK**

BTW if your speed controller has battery eliminator circuitry, or BEC, which means that the receiver works from the main battery and not a separate 4-cell pack then you shouldn't use the 5v red-and-black flylead on the P92. Just leave it unplugged.

DM