I Smell Bullshit Overunity

[BrianHG]

I'd do one if I could find an easy way. Despite having a bicycle there are few places I dare ride with driving being risky round here. So something in the house that I can plug into the grid would be nice, if anything it would mean I could measure my output properly.

I hear you about the safety when you want a serious ride.
Here is what you need for the home made solution, look at the photos below:
1 old fashioned up-write spinner type bike, with seat that adjusts 2 ways, vertically and horizontally.
1 Micro-V groove belt used in exercise equipment, 8-10 v grooves.  Get a long enough belt to sit on the wheel.
1 Used treadmill motor, around 120vdc, with flywheel and Micro-V groove pulley.
Not in photos-
TI switching regulator which goes from 100v to 9v in DC, 6v out.
Either Arduino of PIC board, with 2 channel 12 bit adc.
1 optical sensor on treadmill motor for true RPM feedback.
2 nice big 100v caps.
1 strong mosfet and huge 200-300 watt resistor 2-4 ohm.

Use the MCU board connected to a PC to log voltage and current for power consumption and control motor resistive level VS rpm.
The MCU PWMs the mosfet to control resistive braking setting.

I wont directly recommend feeding power back to the grid for safety reasons, but, there are boxes which can do this and your on your own if you are going to tie your project to the mains.

This design is fairly silent as the treadmill motor is designed to be non-cogging and the Mivro-V groove belt has no bumps or teeth in it.
The belt wont slip on the bike's polished flat steel wheel unless you get sweat on it.  You just need to add a protective cover so your sweat wont come into contact with the bike's wheel.

This design, after friction and DC motor efficiency as a generator is only around 50-60% efficient.  If you want better, the treadmill motor needs to be changed to a 3 phase neodymium permanent magnet low RPM generator.

[Simon]

solar GTI's are in abundance. I have a surplus sunnyboy that will work as low as 125V.

[BrianHG]

With a 120v motor, you will be typically be making 30-50vdc.  Unless you are pedaling at just over 100rpm.
I guess a 240v dc treadmill motor will double your output voltage.  You are left with a narrow pedaling range unless you regulate the output voltage.

Hare was my 2010 setup before I had any electronics, just 2 lamp switches as a test.  It worked so well and unbeliveably smooth that I advanced the project.

[Gyro]

If there's any thread that needs to be free to live, breath and frolic in the sunshine of the Dodgy Technology section, then it must surely be this one. 

[Simon]

I guess an alternator and a cheapo GTI from china

[BrianHG]

Here is a sample of the power logs after I made the controller board, PIC MCU based with optocoupled isolated FTDI RS232 link to a PC which ran a scrolling power and rpm chart & dashboard on the screen as I exercised with a programmed auto gear shift for an interval workout...

Code: [Select]

Log file         Date   Time started   Workout Duration    Surplus power generated in watts.
logs\BikeBrake_05-16-2011_11h31m29s.raw   1:10:10.3     94.37
logs\BikeBrake_05-19-2011_08h34m19s.raw   1:10:08.3     92.38
logs\BikeBrake_06-19-2011_15h28m41s.raw   1:10:13.9     99.89
logs\BikeBrake_06-20-2011_12h35m14s.raw   1:10:10.2     91.49
logs\BikeBrake_06-21-2011_11h06m35s.raw   1:12:44.0     99.88
logs\BikeBrake_06-22-2011_12h24m06s.raw   1:10:06.0     101.35
logs\BikeBrake_06-23-2011_10h46m00s.raw   1:10:11.3     100.46
logs\BikeBrake_06-30-2011_16h42m45s.raw   1:10:08.0     100.60
logs\BikeBrake_07-02-2011_13h44m35s.raw   1:10:13.6     97.37
logs\BikeBrake_07-04-2011_10h47m49s.raw   1:10:09.0     102.89
logs\BikeBrake_07-05-2011_11h44m08s.raw   1:10:10.0     104.29
logs\BikeBrake_07-10-2011_12h56m26s.raw   1:10:08.6     101.98
logs\BikeBrake_07-11-2011_16h36m57s.raw   1:10:12.9     97.06
logs\BikeBrake_07-18-2011_13h12m12s.raw   1:10:09.1     100.71
logs\BikeBrake_07-20-2011_14h00m53s.raw   1:10:12.4     100.42
logs\BikeBrake_07-24-2011_13h41m13s.raw   1:10:20.2     103.44
logs\BikeBrake_08-01-2011_15h37m30s.raw   1:10:10.9     100.62
logs\BikeBrake_08-03-2011_13h47m30s.raw   1:10:11.3     104.12
logs\BikeBrake_08-04-2011_18h02m08s.raw   1:10:15.8     95.95
logs\BikeBrake_08-09-2011_12h59m31s.raw   1:10:14.7     104.57
logs\BikeBrake_08-18-2011_14h22m33s.raw   1:10:14.3     97.13
logs\BikeBrake_08-20-2011_16h52m49s.raw   1:10:10.5     96.79
logs\BikeBrake_08-22-2011_16h52m24s.raw   1:10:11.0     95.79
logs\BikeBrake_08-23-2011_14h59m23s.raw   1:10:06.5     93.97
logs\BikeBrake_08-28-2011_18h03m05s.raw   1:10:13.7     95.18
logs\BikeBrake_09-06-2011_14h59m03s.raw   1:10:14.0     90.67
logs\BikeBrake_09-11-2011_16h45m30s.raw   1:10:16.3     94.06
logs\BikeBrake_09-16-2011_17h30m48s.raw   1:10:15.0     101.04
logs\BikeBrake_09-18-2011_18h15m57s.raw   1:10:16.3     96.54
logs\BikeBrake_10-06-2011_10h59m14s.raw   1:10:33.8     86.90
logs\BikeBrake_10-10-2011_14h31m06s.raw   1:10:23.4     96.37
logs\BikeBrake_10-11-2011_14h32m33s.raw   1:10:14.6     100.29

Lost over 100 pounds over 7 years on that bike.

[boB]

I would settle for "unity" !

boB

[BrianHG]

I would settle for "unity" !

boB

It exists!  In 2 places!
1.  It's called a superconductor.  Charge a ring coil superconductor, and that electrical charge will circulate in it forever free of any resistance.
2.  Cool helium below 4 degrees Kelvin, it then becomes a ZERO friction flowing fluid.  Bump, or hit that fluid to make a small moving fluid fountain, and that fountain will keep on circulating forever, never stopping.  That is unless you warm up the liquid helium beyond 4 degrees kelvin.

[boB]

I would settle for "unity" !

boB

It exists!  In 2 places!
1.  It's called a superconductor.  Charge a ring coil superconductor, and that electrical charge will circulate in it forever free of any resistance.
2.  Cool helium below 4 degrees Kelvin, it then becomes a ZERO friction flowing fluid.  Bump, or hit that fluid to make a small moving fluid fountain, and that fountain will keep on circulating forever, never stopping.  That is unless you warm up the liquid helium beyond 4 degrees kelvin.

Yes infinite circulating current !

But does that include keeping the coolness ? 

boB

[BrianHG]

I would settle for "unity" !

boB

It exists!  In 2 places!
1.  It's called a superconductor.  Charge a ring coil superconductor, and that electrical charge will circulate in it forever free of any resistance.
2.  Cool helium below 4 degrees Kelvin, it then becomes a ZERO friction flowing fluid.  Bump, or hit that fluid to make a small moving fluid fountain, and that fountain will keep on circulating forever, never stopping.  That is unless you warm up the liquid helium beyond 4 degrees kelvin.

Yes infinite circulating current !

But does that include keeping the coolness ? 

boB

Deep space is around 2.7 degrees kelvin. (The temperature of the cosmic microwave background radiation.) So, no need to keep cooling you super conductors/super fluids out there...

[JimRemington]

Here is my homemade exercise bike/generator for phone charging and post-apocalyptic survival.

It uses a 300W 24V scooter motor as the generator, with 1:7 chainwheel ratio, and can comfortably put out 12V/10A while peddling easily, burning calories and losing weight. Along the lines of this thread, it is surely putting out more power than I'm putting in!

Total cost less than US$100 ($13 for the bike at a thrift shop).