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stereophonics29 02-02-2013 08:41 AM

Electrical issues with my grid tied bicycle generator.
1 Attachment(s)
Thank you all for reading/replying to this post, any feedback and suggestion is greatly appreciated.

-Between the crank, rear tire, then to the motor, I have calculated roughly a 40 to 1 gear ratio.

-DC Input
-110V at 3100rpm/29.9amps

-500 Watt Wind Grid Tie Inverter
-22-60VDC Input
-more stats here:

Preliminary information:
I have built a bicycle generator system (see picture) that runs a treadmill motor. I purchased a 500 watt wind grid tie inverter to future proof myself a bit because I plan to install a wind turbine in the future. I have a serpentine belt that is running to the motor and though I am sure some slippage is occurring, it is minimal.

The Problem:
I am not getting the results I had hoped for and expected. Under load to the wall it is extremely difficult to pedal and I max out at about 100watts of energy. I find this perplexing because in my mind there is no way a wind turbine with this type of motor would be able to spin under normal wind conditions. Videos online with similar circumstances do not seem to be struggling like I do, I think there is something wrong with my setup, my thoughts are below.

1. Because I am nowhere close to exceeding the grid tie 500 watt limit, I do not have anything hooked up to the dump load. Is that causing more resistance? If so, is there something simple I can run to it that will correct this since I will not be utilizing it.

2. Most videos that show this being an easier experience are charging batteries, not grid tied. Would battery charging have less resistance than grid tie if it is a simple 12v (4) battery system?

3. One video online shows a scooter battery with stats roughly 400watts @ 2900 rpm/20amps. He is only running a chain from the crank of a bicycle straight to the motor. By employing the rear wheel (increasing the gear ratio) I expected to see dramatically greater results yet he is also able to get 100 watts into a solar grid tie invert under modest physical strain.

4. Under no load I can easily get 60 VDC out so I know the gearing is good.

5. The motor has crossed my mind as a culprit of this as well but all the reading I have done leading up to this suggested that I hit gold with 110v at only 3100 rpm compared to others.

Thank you again!

stereophonics29 02-02-2013 09:52 AM

The stats listed for the motor listed to understand its efficient nature ( or lack there of). I have no delusions of pulling 29amps but those answering this post may need to know what the motor is rated for to accurately understand what a human could produce. My hope was to pull about 250 watts with this setup. I am unaware if volts/amps rise linearly or exponentially with speed but with a 40 to 1 gear ratio of a bike pedal, I hope some estimations are possible.

SPS-1 02-02-2013 05:08 PM

So the max you can create is 100 Watts. Assuming the overall efficiency of the system is 50%, that means your body is producing about 200 Watts. Not sure what kind of shape you are in, but that sounds reasonable for an average person.
You are using a DC motor as generator. Assuming that it is designed for max efficiency near its nameplate speed of 3100 RPM, you are probably running it much, much faster than that with that set-up.
Not sure where the specs on that motor originated, but I serously doubt 29 amps is running into (or out of) that little motor through those little wires.

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