I use a box two 9 speed cassette (for e bikes) 11-50 range,a wipperman stainless steel chain and an American eagle billit hanger 1800+ miles and still perfect shifting,
Hi,I also run th lupine light hard wired to my Yamaha powered Haibike,it draws less than 2amps and runs on 6v (on my bike) the current is varied depending on what bike it’s on,the f model comes with a high/low beam and daytime running lights,personally I don’t see any notable battery drop.