What core cable is a red eye rear light ?

Already have 2 long cable red eyes and the cables aint long enough , want to mount one at the rear of the back as my carradice covers the seatpost and my rack obscures the stays.

Can i simply cut the wire and extend and shrink wrap easily or is it more complex than that ?

Alternatively that can i use my piggyback battery to power the red eye or does it need instruction from the smart port to go ? ( i would try this but my piggybacks in the van in the garage being moted and serviced.)

It’ll run straight off a Piggyback, yep. No smart port needed.

Ah thats good news

Soon itll look like i have twin afterburners coming out the back of my bike …… I dare them to smidsy me then !