Connect with us

Curious about operation of charge controller

Discussion in 'General Electronics Discussion' started by kong, Jan 20, 2014.

Scroll to continue with content
  1. kong

    kong

    122
    2
    Sep 26, 2010
    I found this popular circuit online which was built by Michael Davis for a wind turbine he built. He made his circuit open-source and many people have used it.

    I have no trouble building it but I'm curious about how it works.

    Can someone explain it to me?

    http://mdpub.com/555Controller/images/555ChargeController2.jpg

    Specifically about how the circuit is calibrated to charge/dump.

    Thanks!
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,412
    2,780
    Jan 21, 2010
    It's a very simple circuit that charges the batteries until they hit a certain voltage, then it dumps the power from the solar panels/turbine until the battery voltage falls below another voltage.

    R1 needs to be adjusted so that TP1 is at 1/3*5V (1.67V) when the battery voltage is low (say 12V)

    R2 needs to be adjusted so that TP2 is at 2/3*5V (3.33V) when the battery is fully charged (say 14V)

    Note that this circuit doesn't have any control of the charge current, nor does it take into account the temperature (which causes a change in cell voltage)

    To understand further how it operates, look for circuits using the 555 as a schmitt trigger. The difference in this case is that the 2 inputs are not tied together. This allows control over the switching points and thus also the hysteresis.
     
  3. kong

    kong

    122
    2
    Sep 26, 2010
    Thanks Steve! That answered my question.
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,412
    2,780
    Jan 21, 2010
    Excellent, thanks. I wasn't sure if I was going to an appropriate level of detail or not.
     
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

-