I think this might validate Neil Saiki's (no longer with the company) view on brushed motors for their electric motorcycles (Zero Motorcycles). https://www.you

I think this might validate Neil Saiki's (no longer with the company) view on brushed motors for their electric motorcycles (Zero Motorcycles). https://www.youtube.com/watch?v=0hQ7S3QPSpI https://www.youtube.com/watch?v=0hQ7S3QPSpI They later moved to brushed motors, but I believe that was more for customer demand and not a direct engineering reason. Who knows of the exact solution for brush lifetime in the BMW motor, but one could absolutely have a sweeper, a reservoir and brushes that could last 1M miles or more. Maybe the solution is to have brushes in a cartridge that could be replaced. Only an engineering problem. If the major ingredient into your system is iron, your asymptotic cost is lower than $1/lb. I really appreciate Neil's engineering ascetic, it seems brutally honest.