Register

If this is your first visit, please click the Sign Up now button to begin the process of creating your account so you can begin posting on our forums! The Sign Up process will only take up about a minute of two of your time.

Results 1 to 6 of 6

  1. #1

    Join Date
    Jul 2004
    Location
    Mississauga, ON, CANADA
    Posts
    40
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    25Amp Power supply problem

    I just bought two new 25amp 14volt power supply’s. But I am having problems with the voltage going up and down from 13.8v up to 16.6v. My charger will stop the charge once the input reaches over 16v.

    Can any one give me any ideas how to fix this problem. I was thinking about adding a capacitor in the positive connection. But I don't know if this would work and what size of capacitor to use????

    I am hoping to get 12-14volts at 25amps.

  2. #2
    whitecrest's Avatar
    Join Date
    Aug 2007
    Location
    Orleans, MA
    Posts
    310
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: 25Amp Power supply problem

    Try using a very light load in parallel with your charger. For example, a couple of 12-volt lamps might draw enough current to prevent the power supply voltage from rising over 16 volts and tripping your charger. A resistor with a low enough value could accomplish the same thing. A few hundred ohms might do the trick. You would have to experiment with the values.

    I would also verify if both power supplies behave the same way. Perhaps one of them is faulty and has a bad regulator circuit. If both are the same, then providing a light, constant load should prevent the voltage from spiking up as your lipos finish charging. Good luck with the trouble shooting.
    Tim

  3. #3

    Join Date
    Jul 2004
    Location
    Mississauga, ON, CANADA
    Posts
    40
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: 25Amp Power supply problem

    I have added a resistor which has lowed the voltage but I having problems with the high and lows in the voltage. Would a capaictor help with this????

  4. #4
    jdetray's Avatar
    Join Date
    Dec 2004
    Location
    Napoleon, OH
    Posts
    1,617
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: 25Amp Power supply problem

    An honest-to-goodness regulated power supply should not do what you are describing. If the voltage is varying that much, then either it's not a regulated supply or it is defective. Most chargers require a regulated supply.

    Are these power supplies originally intended for use in some piece of electronics equipment? Power supplies that are built for a particular purpose (and a particular load) sometimes don't work well as general-purpose power supplies. They only work properly with the load for which they are designed.

    An example is certain types of personal computer power supplies which require a load on their 5V line in order for the 12V line to provide the proper voltage.

    - Jeff
    My other hobby: www.AstronomyBoy.com

  5. #5
    whitecrest's Avatar
    Join Date
    Aug 2007
    Location
    Orleans, MA
    Posts
    310
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: 25Amp Power supply problem


    ORIGINAL: RC Technics

    I have added a resistor which has lowed the voltage but I having problems with the high and lows in the voltage. Would a capaictor help with this????
    As stated above, I agree that your power supplies don't appear to be regulating properly and may have been designed for some other purpose. One clue may be that you're getting a high voltage reading of about 16 volts which is somewhat high for a general DC supply. They are usually rated for about 13.8 volts which will drop just a bit when supplying current within it's design range. The loaded voltage should stay within a fairly tight range if the regulator circuit is working properly. These supplies usually have very large filter capacitors, so adding more is not likely to make any difference.
    Tim

  6. #6
    -pkh-'s Avatar
    Join Date
    May 2004
    Location
    Emmaus, PA
    Posts
    3,354
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: 25Amp Power supply problem

    If it's an unregulated supply and you are seeing ripple voltage on the output at high currents, then an additional cap will help. However, at 25A, you'll need a pretty big cap to make much of a difference. I've got a 24V 20A unregulated supply that has a filter cap the size of a soda can!

    Is this a switching supply, or a transformer-rectifier-filter type supply? How are you measuring the output voltage, & seeing it vary from 13.8 to 16.6V? Are you looking at it on an oscilloscope?
    Paul - Helis: Two Raptor 50V2s, Venture 30CP, Blade CX2
    Planes: Twist 60, Tribute 36, Two PZ BL P51s, Two F27C Strykers


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
All times are GMT -6. The time now is 10:14 PM.

SEO by vBSEO 3.6.1 ©2011, Crawlability, Inc.