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## Main Question or Discussion Point

I'm a mechanical engineer getting confused with electrical engineering...

I've made an electrical generator by spinning the shaft of a DC motor by connecting it to my bicycle.

I've tested it with a multimeter, and on 1 kOhm, 2kOhm, 3kOhm, and 4kOhm resistors I'm producing about 70 Volts. Current is varying accordingly with V=IR. Therefore power P=IV is increasing as resistance decreases.

My question is how do I find the optimum resistance to produce the most electric power? By this calculation, power would increase as resistance decreases. However there has to be some limit to this, as I was only putting in about 200 W into the bicycle. According to the equations a 10 ohm resistor would lead to 7 amps and 490 W, but obviously I'm not producing more power than I'm inputting.

Can someone please help me approach this problem? What is the optimum resistance for optimum power?

I've made an electrical generator by spinning the shaft of a DC motor by connecting it to my bicycle.

I've tested it with a multimeter, and on 1 kOhm, 2kOhm, 3kOhm, and 4kOhm resistors I'm producing about 70 Volts. Current is varying accordingly with V=IR. Therefore power P=IV is increasing as resistance decreases.

My question is how do I find the optimum resistance to produce the most electric power? By this calculation, power would increase as resistance decreases. However there has to be some limit to this, as I was only putting in about 200 W into the bicycle. According to the equations a 10 ohm resistor would lead to 7 amps and 490 W, but obviously I'm not producing more power than I'm inputting.

Can someone please help me approach this problem? What is the optimum resistance for optimum power?