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Lead acid battery trickle charger questions

Discussion in 'Electronic Basics' started by Rubicon, Jan 12, 2004.

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  1. Rubicon

    Rubicon Guest

    Hello,

    My uncle bought a little charger from a garage sale and it doesn't
    appear to work so passed it on to me to have a look at.

    Lead acid battery trickle charger 12/6V 1.2Amp max, 0.5Amp mean.

    The mains transformer has three output wires for 12V and 6V. The wire
    goes to a, AC~ lead of a bridge rectifier, the second and third to the
    outer terminals of a SPDT rocker switch for 12 or 6V. The common
    terminal is connected to the second AC~ lead on the bridge rectifier.
    A DC lead of the rectifier goes to the + terminal of the car battery.
    The batteries negative terminal connects to a thermal switch which
    connects to the (the part I don't understand) positive "Charging" LED
    lead via its 330Ohm/1Watt resistor and then goes back to the second
    rectifier DC lead. The resistor is so badly burnt I had to measure it
    but there's also a broken bare wire on the LEDs negative lead and
    another on the thermal switches terminal to the resistor. It's like
    fusewire and as if they were joined but if joined they cut the LED and
    resistor out of the circuit. I don't know what it's there for. Any
    ideas on what its function is?

    Perhaps I can't see the woods for the trees here.

    Cheers,

    Andrew.

    Remove the ZZ from E-Mail address to contact me.
     
  2. Try
    --
    We now return you to our normally scheduled programming.

    Take a look at this little cutie! ;-)
    http://home.earthlink.net/~mike.terrell/photos.html

    Michael A. Terrell
    Central Florida
     
  3. Ross Mac

    Ross Mac Guest

    Cute dog Mike....do you live in Ocala? Just curious...was thinking about
    relocating from California....
     
  4. About five miles south of Ocala.

    --
    We now return you to our normally scheduled programming.

    Take a look at this little cutie! ;-)
    http://home.earthlink.net/~mike.terrell/photos.html

    Michael A. Terrell
    Central Florida
     
  5. Ross Mac

    Ross Mac Guest

    Any suggestions on towns around the Ocala area...perhaps waterfront
    property?...Thanks in advance, Ross
     
  6. There aren't many towns in Central Florida without waterfront
    property. I would suggest you make a visit to the area, and visit
    different towns to find what you are looking for. The Ocala area, and
    several nearby places are full of retirees, golf courses and such. Other
    areas of Florida are better for finding jobs. Ocala is full of itself
    over their horse farms. If you want a place with lots of water, take a
    look at lake county, just south of Ocala, but be warned, the soil is
    mostly sand from there, south.

    --
    We now return you to our normally scheduled programming.

    Take a look at this little cutie! ;-)
    http://home.earthlink.net/~mike.terrell/photos.html

    Michael A. Terrell
    Central Florida
     
  7. Ross Mac

    Ross Mac Guest

    Thanks Mike.....I was just looking for an inside look...I am headed there
    next month...take care, Ross
     
  8. If you are going to be in the Ocala area E-mail me and I'll give you my
    phone number.

    --
    We now return you to our normally scheduled programming.

    Take a look at this little cutie! ;-)
    http://home.earthlink.net/~mike.terrell/photos.html

    Michael A. Terrell
    Central Florida
     
  9. Andrew,

    If you're gonna fix it, exercise caution around the 120 volt
    connections and transformer primary wiring!

    The resistor and LED are there to indicate there is output
    voltage and the thermal switch has not tripped. Purchase
    any regular flavored LED as replacement and use ohms law to
    compute your series resistor (ask at radio shack or use
    their 12 volt version that has a resistor already
    installed).

    To fix the unit, first check the output of the transformer,
    then input to the AC~ leads of the bridge rectifier in 6 and
    12 positions for AC voltage. If present check for DC
    voltage between the + and - of same. If both are ok and
    there is no output at the clips, short the thermal switch to
    check if that's the problem.

    If you don't have a meter, use at 12 volt test lamp for AC,
    with a diode for DC (presence is more important than
    polarity as long as the output red clip routes to the +
    terminal of the bridge rectifier).

    If replacing the LED, have + of bridge route to the anode
    lead, - to cathode lead, either through appropriate
    resistor. A regular red diffused LED will set you back
    about a dime, and can use a 680 ohm 1/2 watt resistor (1
    watt is better if it's near anything generating heat) - but
    you can also just forget these [parts if you feel like it
    and check output with any 12 volt lamp if you hear the
    thermal cutout clicking...

    Good luck and remember not to touch the 120V wiring (it
    HURTS <s>).

    By the way, a transformer can be had at most surplus or
    electronic stores for 2 1/2 to 10 bucks, the bridge
    rectifier for a buck or two, and the thermal cutout may be a
    mail catalog item. These come in handy to throw under the
    hood, so if it were me, I'd rather fix it than scrap it.

    Good luck!
     
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