hello

[cherrytree]

I live in Belfast and am new to electric bikes. I bought a kit of ebay for my brother. Its a 36v 250w front wheel. Conhismotor I think.We used 3.6v li-ion batteries, 11 in series to power it.This worked for about 2 mile and then stopped. Now its developed a fault. Until about 3/4 throttle it turns slowly. on full throttle it goes for about 2 seconds then cuts out for about 2 seconds and then goes again for about 2 seconds and so on. Has anyone any idea what would cause this. As I am new to pedelecs any advice will be appreciated.