Featured Articles
Announcing Pi
Technical Specifications
Raspberry Pi FAQs
Win a Pi
Raspberry Pi Wishlist
Actions
Forum Thread Details
  • Replies 3 replies
  • Subscribers 662 subscribers
  • Views 1672 views
  • Users 0 members are here
Related

DC Motor Generator for Raspberry Pi

mwdy319

I am trying to do a project that essentially utilises high torque DC motor as a power generator to power a raspberry pi 0W.

The idea is to create some sort of kinetic energy converter that converts motion applied to the motor into electrical, store it into a power bank or batteries (show in the flow chart).
How much power would it require to be able to fully run a RPi0W?
How much power can a single DC motor produce? How powerful or quick of a rotation to produce a certain amount of power?
What is the best (available) DC motor I could use for this generator?

Cheers


Attachments:
image

  • How will you drive the generator ?

     

    The rules are simple - the generator will convert about 80% of the mechanical energy into electricity, more (but never 100%) if it's a good one, less if not.

    The best source of new good cheap generators is those intended for bicycles - about powerful enough to keep a pi going, typically they manage about 3W.

     

    The power input (or output) from a motor = 2pi * torque * revs.

     

    If the torque = 1Nm and you manage 60RPM you'll get 6.28W

     

    I didn't find any good products on the web but I didn't look long. The guy in this video says several things that are not correct but it'll give you an ideas of just how hard you have to work

    to generate about 5W. It's a very inefficient design - look how much human is moving about compared with generator, a lot of wasted energy there.

     

     

    Your Pi will need about 1W (depends a lot on what you enable and what it's doing)

    Really fit humans can produce maybe 2000 W peak (for a few seconds) and 350W for an hour.

    You need a very efficient machine to extract the power from the human - bicycles are good at it.

     

    Do some Googling  - there's a lot of stuff out there , but no free lunches - you have to work to make electricity.

     

    MK

  • in reply to michaelkellett

    The motor will be implemented onto another thing. It will essentially have a handle that can help the user rotate it. That's how the motor will be driven.

     

    3W sounds sufficient. What are these generators for bicycles, if I may ask?

    Also what is the video you were referring to?

    2000W per a few seconds seem A LOT, dont you think?
    Also this design will have kind of a direct conversion, in the sense that the motor will acquire the motion directly from the "handle" (I mentioned above) and drive the motor directly.

    Do you happen to know how I can charge a battery from the generator? What the electrical circuit is like? And do you know how I can use the battery and use it at the same time? Charge it when the motor is driven, and used (energy consumed) by the raspberry pi at the same time.

    Cheers.


  • in reply to mwdy319

    I think you need to explain what it is you are trying to do.

     

    All these things exist, use Google and Amazon to find stuff.

     

    Bicycle generators are for working the lights on a bike - Amazon sell lots and lots of different kinds. Some with chargers and stuff for phones.

     

    I seemed to have lost the link for the video, can't find it again since I cleared up my hsitory and stuff yesterday.

     

    Google for Human Powered Generator

     

    2kw for a few seconds is a world class sprint athlete for a few seconds - cranking a handle for 10 minutes you'll do well to get 10W, an average person should manage 50 - 100W for an hour on

    a well designed bicycle like generator.

     

    MK