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trickle charger

Discussion in 'Misc Electronics' started by Damien, Nov 8, 2003.

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  1. Damien

    Damien Guest

    I'm trying to find a circuit diagram for a trickle charger capable of
    charging a 12V motorcycle battery. I've got a 4A charger which works well
    enough, but a trickle charger would be preferable for helping ensure the
    battery has a long life. I've looked everywhere I can think of online except
    for here, and was hoping someone might be able to help!

    Damien
     
  2. Jerry G.

    Jerry G. Guest

    It would be much more reliable for you to buy a trickle charger that is UL
    or CSA approved. Use a 1 or 2 amp charger that is designed for motor cycle
    batteries with an auto cut-off. If you build one yourself, and there are
    defects, you can end up damaging the battery, and having a chance for a
    safety hazard.

    --

    Greetings,

    Jerry Greenberg GLG Technologies GLG
    =========================================
    WebPage http://www.zoom-one.com
    Electronics http://www.zoom-one.com/electron.htm
    =========================================


    I'm trying to find a circuit diagram for a trickle charger capable of
    charging a 12V motorcycle battery. I've got a 4A charger which works well
    enough, but a trickle charger would be preferable for helping ensure the
    battery has a long life. I've looked everywhere I can think of online except
    for here, and was hoping someone might be able to help!

    Damien
     
  3. Bill Bowden

    Bill Bowden Guest

    You can use the 4A charger you have to trickle charge.
    Just add a 20 watt automotive tail lamp between the charger
    and battery. That will keep the current below 2 amps and
    if you want less, use two light bulbs in series.

    -Bill
     
  4. Tweetldee

    Tweetldee Guest

    This is not a good idea. If you want a trickle charger that you can leave
    connected to your battery for extended periods of time, then it's best to
    get a charger that has two charge modes.. full charge and trickle. Or,
    have a trickle charger handy to connect when your 4A charger has done its
    job.
    The reason is that a lead-acid battery needs a constant voltage charge...
    one that limits the charging voltage to the "float level" of lead-acid
    batteries... 13.6 - 13.8 volts. The lamps will do nothing to limit the
    voltage to the battery after full charge has been reached.
    Fully charged batteries have a terminal voltage of 13.6 - 13.8 volts (the
    float level). After that state has been reached, more charging will result
    in boiling the electrolyte, outgassing, quickly damaging the battery. The
    current needed at a float charge rate is only a few milliamps...
    significantly less than the 2A suggested. It's the voltage that needs to be
    limited, not the current. When you have the correct float voltage applied,
    the battery will draw only the current it needs to stay fully charged.
    The lamps will serve to limit charging current when the battery is
    discharged, but your 4A charger really doesn't need the lamps.. it's
    self-limiting.
    Harbor Freight has a trickle charger in their online store that would do the
    job for you. It's their item # 42292-0VGA, $14.99 USD.
    --
    Tweetldee
    Tweetldee at att dot net (Just subsitute the appropriate characters in the
    address)

    Never take a laxative and a sleeping pill at the same time!!
     
  5. Bushy

    Bushy Guest

    Add a resistor to one of the leads and continue to use your charger.

    Peter
     
  6. Damien

    Damien Guest

    Yes, I could buy one, but where's the fun in that?! :) Also, I'm in
    Australia so by the time you factor in exchange rates and postage, I'm
    looking at a good $50, not to mention a wait of at least several weeks.
    There are trickle chargers available here for around $65AUD, but it would be
    a lot more fun and satisfying to make one myself! I'll buy one eventually if
    I have to, but I'd rather make one if I can find a good design that is cheap
    to build.

    Damien
     
  7. Bill Bowden

    Bill Bowden Guest

    I was assumming the charger shuts off at 13.6 volts.
    If not, he could use a LM317T voltage regulator and
    two resistors to set the voltage to 13.6. The current
    is limited to 1.5 amps but the input must be at least
    2 volts higher than the output, so the charger will have
    to deliver around 16 or more open circuit to maintain
    13.6 out. The regulator costs 58 cents at digikey and
    the resistors are about 5 cents each.

    See this link:

    http://ourworld.compuserve.com/homepages/Bill_Bowden/page12.htm#317.gif

    -Bill
     
  8. Damien

    Damien Guest

    I've also found circuits at:

    http://www.electronic-circuits-diagrams.com/carsimages/carsckt1.shtml

    and

    http://www.uoguelph.ca/~antoon/circ/lader.htm

    Only problem with the first one is the scanned image of the schematic is a
    bit too fuzzy to read. Of course, the other problem is that I have no idea
    which would be the best to build - yours seems to be the simplest, and would
    certainly do what I want, but would there be any advantages to using one of
    the others? Or any particular reasons why I should _not_ use them?

    And thanks to everyone else who has also posted replies - I've got a hell of
    a lot more to go on now than I did before!

    Damien
     
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