To clarify, because I think it was pretty cool, the general principle of John's mod was that the percentage of the shunt wrapped in copper would have almost no resistance. So if the shunt is wrapped 50% in copper, resistance is down 50%, amps are double [Half that if there are two shunts and you only cover one 50% that's 25% of the total]. I believe this is the general principle, and it's supposed to be somewhat more accurate. please correct me if I'm wrong.
New to endless-sphere? Notice a lot of signatures recommending Ebike.ca? That's because it's the best place for a quality and manageable, (but still 'real'), first build. Justin is a solid supporter of electric bike development, and a good source of equipment.
My hat off a thousand times to the green people that effectively run this forum. The ES Mods are superb.