I want to use a dc motor to charge a cellphone, how would I choose an off the shelf dc motor to use as the generator? I am looking at something like this https://www.amazon.com/2-5KG-Micro-Speed-Reducing-Motor/dp/B009AQLDSS/ref=pd_day0_469_2?ie=UTF8&psc=1&refRID=K49X1E2DXFR58MMTJ742. I am assuming if I can match the rpm it should be close to the running specs? I would like a similar current but higher voltage to step down to 5 volts, however I am think a buck/boost converter would be adequate?
