Electricity generation with a bicycle and a car alternator

Experience report Electricity generation by bicycle and a car alternator

Since I had planned to generate 10 KWh of electricity in 2012 and had reached just 6 KWh as of 31.10.2012, a plan B had to be realized.
Unfortunately the provisional generator for the self-construction vertical axis wind turbine proved to be not helpful.

The required wind strength to get to charging voltage is simply too high.
So if the sun does not shine and the wind does not blow, only muscle strength still helps.
A person can produce between 100 and 200 watts for a relatively long time.

Examples from the Internet

The energy generation by means of muscle strength is nothing unusual, can be read on the pages of Buch der Synergie.

There are professionally built generators for the montage at the bike, but they cost a little.
Then I looked at Youtube and am found there something helpful.

Some time ago I had found a discarded car alternator and dragged them on suspicion times home.
A little bit in the net searched and a nice description to the three-phase alternator found.
I bought a corresponding V-belt at Ebay.


On 1.11.2012, a frame was then provisionally made, in which the bicycle can be clamped and the V-belt drives the alternator.
After about 5 hours of tinkering, it was possible to step into the pedals and the alternator spinned.

In order to test whether the alternator works at all, I have a 4.5 volt plug-in power supply (was available) closed to the excitation winding and connected to the output side a 6V 21 Watt bulb.
What was immediately noticeable was, that it was hard to step into the pedals. The 21 watt lamp started to light, burned brighter and burned right through.
What a success.

I have as in the video above to see also a switch to turn on the excitation winding attached and the whole test arrangement in the garage next to the 12V battery built up.
When the excitation current was switched on, an extreme resistance was noticeably.
One minute stepping into the pedals and the battery’s charge voltage rose from 12.95V to 13.2V.
But after a minute, my personal performance was at an end.

Ich gehe davon aus, dass ein permanenter (starker) Erregerstrom nicht optimal ist.
Pulse width modulation may be an approach.
I have an ATMega8 microcontroller already in use, to let generated energy consume and to measure how much was consumed.
The ATMega8 microcontroller has 3 PWM outputs, so it can take over this task immediately.

The circuit diagram of the exciter circle is somewhat more complex.
There the current flows with up to 2 amps at max. 14.4 volts. With the ATmega8 with 5V and max. 40mA per output pin this requirement can’t be realized.
On the following circuit diagram for the control and another I oriented myself and finally I purchased at Pollin the SUD45N05-20L.
Tailored to my needs, the schematic should look like this.

[will be continued]

3 thoughts on “Electricity generation with a bicycle and a car alternator

    • Ich hatte mich vor ca. 2 Jahren etwas damit beschäftigt. Leider ist es aus Zeitmangel etwas aus dem Blickfeld geraten.
      Ich bin aber fest der Meinung, dass es sich gelohnt hat in die Richtung etwas zu unternehmen. Sobald wieder etwas Luft ist gehts weiter :-)

  1. Habe Gleiches mit einem alten Gleichstromgenerator gemacht; hata funktioniert, aber der Elan zum Treten ist bald geschwunden, so dass ich das gebastelte Monstrum aus Platzgründen wieder demontiert habe.
    Aber die Idee fasziniert mich immer noch, auch die mit Windrad.

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