Smart exercise bike computer. Part #5: Experiments with power generation

RE: Smart exercise bike computer. Part #5: Experiments with power generation

aspork42 — Wed, 13 Jun 2018 04:50:24 GMT

Great update! Looking forward to the next one!

RE: Smart exercise bike computer. Part #5: Experiments with power generation

mcb1 — Mon, 11 Jun 2018 01:38:52 GMT

[mention:bcf467be9bf04982b313a2229455ef3a:e9ed411860ed4f2ba0265705b8793d05]

Nice update and demonstration of the issues.

One figure not shown is the free running speed of the motor.

Unless you can rotate the generator at close to the required speed, surely it will not produce full power?

I suspect that some of your slippage issue is caused by the mechanical coupling.

You have a very small surface area between the drive surface and the fully loaded generator, along with no ability to increase the pressure on the rubber wheel.

You may want to try a larger rubber wheel and have the generator much closer to the wheel, so you can add pressure to stop it slipping.

Unfortunately that also slows down the rotational speed of the generator shaft, so you gain and lose. [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-5b5b5b67-b3b8-4156-8446-95caf28ce38c/contentimage_5F00_2.png:16:16]

In theory you should be able to spin the flywheel using the motor, but it could be a little underpowered and require the magnetic drag to be removed.

This will prove the slippage has been eliminated.

Cheers

Mark

RE: Smart exercise bike computer. Part #5: Experiments with power generation

three-phase — Tue, 05 Jun 2018 21:23:57 GMT

Another excellent addition to your series. As others have said a great mixture of theory and validation makes an interesting read.

Kind regards

RE: Smart exercise bike computer. Part #5: Experiments with power generation

DAB — Tue, 05 Jun 2018 17:09:13 GMT

Nice update.

Brings back memories when I put a generator on my bike to power a light back in 1962.

DAB

RE: Smart exercise bike computer. Part #5: Experiments with power generation

BigG — Tue, 05 Jun 2018 16:12:20 GMT

Wow, nice update. I like the mix of theory and then verification.

Say, have you considered removing the battery altogether and replacing with a super capacitor, for example. Then, as a suggestion, maybe you should look into energy harvesting power management (PMIC's) to power the MCU. I know Cypress have stuff that could work with those sort of voltages.

http://www.cypress.com/products/energy-harvesting-pmics

RE: Smart exercise bike computer. Part #5: Experiments with power generation

genebren — Tue, 05 Jun 2018 13:52:16 GMT

Nice update on your design challenge project! I wonder if you were to add some gearing to increase the speed of the generator further, would you be able to get your output voltage up high enough throughout the pedal speed range to charge your battery? Would a larger generator achieve the same result without the gearing. If the current motor, produces enough energy at the lower speeds, maybe you could use a boost regulator to increase the voltage high enough to allow charging at lower pedal speeds?

Good luck on getting your package in time to continue your development. I look forward to your future updates.

Gene