How to Build an Efficient Electric Generator from Peddling

The Otherpower discussion board is a treasure trove of information on building homemade axial flux generators. These generators are ideal for cycle power generation, providing a versatile and sustainable solution for various applications.

Understanding Pedalling Efficiency

For a non-cyclist, generating power through pedalling can be challenging. A well-conditioned and experienced cyclist might generate around 100-150 watts for a half hour or so, but only in shorts and with moving air. On the other hand, a non-cyclist can expect to generate only about 50 watts in street clothes.

Optimizing Pedalling Speed with Gearing

When utilizing a single-stage roller chain bicycle gears, a practical gear ratio of 5:1 can be achieved using standard cog and chain rings. This means that to achieve an optimal speed within the axial flux design's good speed range (around 300 rpm), a non-cyclist may need to pedal at approximately 60-75 rpm. Higher speeds using additional gearing might prove to be highly inefficient at high power levels.

Designing and Mating Magnet Assemblies

The biggest challenge in building an axial flux generator lies in the magnet assemblies, especially when considering the lack of access to a lathe for precise machining. A welder can be extremely useful in overcoming this challenge.

Economic Considerations and Potential Uses

Despite the potential for generating power through human pedalling, the economic viability of doing so is quite limited. Human labour is far too expensive: it would cost hundreds of dollars in food to generate a single dollar's worth of power.

The idea of pedalling to make a little bit of power (possibly earning a penny an hour) could be a good go-for-it project, especially if the participants are overweight and can lose weight in the process. However, this approach is not economically useful and does not justify the cost of food and energy input.

For more practical applications, it's important to explore other methods of generating electricity from human effort. These methods should provide a higher net value and help in achieving both economic and sustainability goals.

Conclusion

In conclusion, while building an electric generator from human pedalling can be an interesting project, it is economically non-viable for large-scale power generation. However, it can be a valuable educational and community project for those interested in sustainable energy practices and personal health.