Reverse dc motor to create energy to charge 12 volt battery??

Question

what size dc motor would i want to use, like about how many rpms should it be

what i want to do is to take an electric dc motor to and somehow how turn the shaft to create electicity to charge a 12 volt marine battery, i know it is possible because they sell the bikes that spin the motor to create electricity, butt i dont want to spend all that money

Answer 1

Why not buy a used automobile alternator? They're designed for precisely such service. Most alternators come with the rectifier diodes and many have the regulator built-in. If you're planning to charge this battery by human power, your legs are the best energy source and a bike-based approach is best. Any used bike will do, preferably a 10-speed. You can make a drive belt loop by joining the ends of a length of rubber tubing. With that you can couple the rear wheel to the alternator pulley. Then use the gearshift to pick the most comfortable ratio.

Answer 2

Depends on the motor, it's size, how fast you spin it, how much current you need.

Buy one and try it.

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Answer 3

You have described an engineering problem, but without the details necessary to solve it.