Make it Monday: Exercise bike to Pedal Generator

The Challenge

Back in November we set ourselves a 24 hour challenge to turn this pre-loved exercise bike in to a pedal powered generator. Its speedometer and tension belt were broken so it had been passed on to us as it no longer suited its original purpose. This is our step by step guide for how we transformed it - it's different for every exercise bike, but this may give you an idea of how to approach a similar project. Feel free to get in touch with us if you need more information!

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Swap out flywheel

We struggled to incorporate the heavy flywheel in to this design and so opted to replace it with a back wheel from a small child's bicycle. This can be a tricky part of the process, luckily with this exercise bike it was relatively simple to swap out, but with some you may need to do some hunting around car boots sales to find the right wheel size to fit. We also changed the tyre to a slick 12" pram wheel as this is more efficient when directly running the generator off the tyre.

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Set up generator

Now the important bit... to create the pedal powered generator we chose a permanent magnet motor that was originally used for an electric bicycle. If you can't find one of these you can find them on Ebay or similar sites. We have also used motors from car engine fans, which are very easy to pick up from reclamation yards. For this project we used a 24volt 250watt motor which had a screw on nut on the end of the shaft. We then took off the small metal wheel from an old dynamo bike light set, drilled it out slightly to fit over the shaft, and then used the bolt to tighten it.

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Attach generator

We chose to attach the generator to a board for this design, mainly because it will be used by children and we wanted something very stable for our events. To do this we used strapping to screw down the exercise bike to a large piece of spare plywood.  Take the generator and position it under the wheel so it is touching the rubber tyre with slight pressure. This takes a little adjusting, so it is best to connect a voltmeter/watt meter to the wires to get an idea of its efficiency. Screw the generator down on to the board when you are happy that it is generating the optimum amount.

Finishing touches

We added some antlers,  a saddle for a head and some button eyes to create Rudolph. With some simple wiring we also hooked up a very shiny pedal powered nose for him. We'll be posting a 'Make it Monday' for saddle covers too in the near future.

And for those of you that worry he's redundant for the rest of the year... He is easily altered in to a pedal powered horse to generate electricity for our bicycle caravan!

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Looking to build you own Pedal Powered Generator? We hope you've found our brief introduction useful, we will be blogging in more detail about our DIY pedal generators soon so watch this space. In the mean time let us know if you've got any questions and we'll do our best to help.