I use these now in all my bots. Plug right into the receiver on a spare channel and turn on when the receiver turns on. Just chop any lights you don't need (I tend to only use one) and insulate any cut wires.

https://www.ebay.co.uk/itm/Upgrade-L...sAAOSwsW9Y28JR

The fuse has to be rated to be less than the burst rating of your lipo pack. Figure out the burst rating and size accordingly.