Simple LED wiring help

Discussion in 'General Electronics Chat' started by guitarguy89, Sep 14, 2014.

  1. guitarguy89

    Thread Starter New Member

    Sep 14, 2014
    Alright so,
    I've done a few small wiring projects before but I can't really figure out what's going on.
    I just bought my girlfriends son one of those 12V ride on cars for kids. It works great and he loves it. But I got the wise idea to ad lights to it. So I drilled out the backs of the headlights and side mirrors, as well as the brake light in the spoiler. Altogether I'm running 6 5mm red led's and 2 jumbo white ones. (I believe they are 10mm) so when I hook up the power to the 12v battery, nothing.
    Do I just need more power?
    I have all of the positives wired together and all the negatives wired together
  2. Lee697

    New Member

    Aug 31, 2014
    Are they LED bulbs/lights, or plain component LEDs?? If they are bare component LEDs they are probably dead (after a very brief flash of light!) if you didn't use an appropriate current limiting resistor...
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    LEDs need to be fed a constant current (resistor or LED driver) or they will just burn up and the dc output voltage needs to be greater than the sum of the forward voltages of all LEDs in the series string.

    You probably need to split your LEDs up into 2 series strings with a current limiting resistor on each string..

    Tons of LED calculators out there to calculate the resistor value for you..
  4. Lee697

    New Member

    Aug 31, 2014
    If you solder a resistor to each, you can parallel them in a similar way you tried....
    Standard LEDs on 12V, I'd use around 500 Ohm resistor, for approx 20mA current through the LED....
  5. ian field

    Distinguished Member

    Oct 27, 2012
    You can also get LEDs with a built in current limiting chip, needs 1 per series chain and needs checking for same current as the others in the chain - especially the jumbo LEDs.