Connect with us

Low Amperage battery charging.

Discussion in 'Power Electronics' started by MadMechanic, Dec 5, 2012.

Scroll to continue with content
  1. MadMechanic

    MadMechanic

    48
    0
    Aug 28, 2012
    Hello All,

    I have a general question about battery charging. I am messing around with small scale power generation (as some of you may have seen in previous threads) and I have a question about battery charging.

    Originally I was aiming to generate enough power to charge any USB device with only my generator. USB standard power is 5V, 1A. So far I have had success charging a cell phone at 5V 300mA with no problem. I have tried larger loads, but it seems my generator is maxing out around 350mA when I increase rpm. I have not yet tried my ipod touch which should draw anywhere from 500mA to 1A.

    I have plenty of voltage out of this.... easily in excess of 50V at low rpm, but the amperage seems limited, even though the motor I am using in reverse as a generator is rated at 1.7A.

    The question is If I were to add a 12V rechargeable battery to the system as the primary phone charging source, could I (trickle-charge) the battery from the generator? Being that the generator's amperage is lower than the load on the battery....would the battery recharge at 350mA when not loaded?

    Would I be safe to assume that as long as the battery has (non-loaded) resistance lower than the pull of 350mA that as long as my voltages were even or greater the battery would slowly recharge? Thanks,
     
  2. davenn

    davenn Moderator

    13,654
    1,888
    Sep 5, 2009
    Is that 50V or so an open circuit voltage or one with a load

    the curent will probably, mainly, be limited by the thickness of the wire used in the windings

    Dave
     
  3. MadMechanic

    MadMechanic

    48
    0
    Aug 28, 2012
    50V is the open reading across the meter. I got it up to 35V by twisting the shaft with my fingers believe it or not. Im using a stepper motor wired in Bipolar parallel with 4 sets of leads across 2 separate full bridge rectifiers in series with two 4700uF capacitors. I seem to get more voltage and less amperage with the motor in Bipolar series orientation.

    Should I possibly try to find a motor with a larger winding gauge? I would love to get 1A total out of one of these after rectification.
     
  4. davenn

    davenn Moderator

    13,654
    1,888
    Sep 5, 2009
    yeah that would be an idea :)
    stepper motors would be very inefficient for power generation

    Dave
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-