Tell us about yourself!
8amps is nothing for a 4s lipo. I use 4s lipo packs made for high discharge on my drones and they can deliver a peak of well over 100 amps, and never really dip below 30 amps during the whole flight. 8amps is actually so low, he shouldn't be using a lipo, he should have used a Li-ion pack instead so that he'd have more power density. A 18650 array would be perfect for something like this, and you could get cells with their own discharge protection. This design in the video seems to use only the low voltage alarm as battery protection, so if you leave the light on the battery could destroy the lipo and possibly start a fire.
How much did the copper cost? I love making things with pipe but fitting prices are ridiculous.