NEED HELP

Discussion in 'The Projects Forum' started by lildiesel6075, Mar 25, 2006.

  1. lildiesel6075

    Thread Starter Member

    Mar 7, 2006
    21
    0
    [quote author=sain link=topic=2868.msg42588#msg42588 date=1142904690]
    actually its pretty easy to do - you just use an opamp as a voltage comparator - comparing the battery voltage and a reference voltage. The reference voltage should be whatever you want the battery charged up to (use a voltage divider off a constant 12v src). The output from the op amp is fed into a transistor which switches the constant current source charger on and off.

    I'll find the schematic for the one I built eventually - its somewhere on a spindle of backups cds. In the meantime you can figure it out from that description, it'll make a useful exercise
    [/quote]

    This was from afromans forums, afro and i tested the charger and verifed that it works amazing w/o spending liek 20 bucks on a another charger,

    But i need help building wat sain said, i wanted to know could i make my voltage source automatically cutoff when the battery is finished charging.

    I could ask afroman and see if he could help, (becuase he has all the brains, i just got a big electronic workroom, flame free, and i test his experiments,) but afroman isnt reply to me on aim.

    SO i came to yall to see what yall think about it.
     
  2. lildiesel6075

    Thread Starter Member

    Mar 7, 2006
    21
    0
    looks like the quote didnt quile work. lol
     
  3. pebe

    AAC Fanatic!

    Oct 11, 2004
    628
    3
    This was from afromans forums, afro and i tested the charger and verifed that it works amazing w/o spending liek 20 bucks on a another charger,

    But i need help building wat sain said, i wanted to know could i make my voltage source automatically cutoff when the battery is finished charging.

    I could ask afroman and see if he could help, (becuase he has all the brains, i just got a big electronic workroom, flame free, and i test his experiments,) but afroman isnt reply to me on aim.

    SO i came to yall to see what yall think about it.
    [post=15419]Quoted post[/post]​
    [/quote]
    I can't see what 'it' is. Can you provide a circuit?
     
  4. lildiesel6075

    Thread Starter Member

    Mar 7, 2006
    21
    0
    I can't see what 'it' is. Can you provide a circuit?
    [post=15422]Quoted post[/post]​
    [/quote]

    below is a my batteryu charger, but i wanted to know how to make it automatically cutoff when the battery is finshed charging.
     
  5. pebe

    AAC Fanatic!

    Oct 11, 2004
    628
    3
    You have a simple constant current charger, so the voltage across the battery will rise as it becomes charged. You could sense that voltage make a cutoff circuit.

    Do you know the battery voltage when it is passing 65mA and is
    1) 95% charged, and 2) fully charged?
     
  6. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Try using a flux capacitor.

    Better yet, try reading up on op-amps. Click here for Op Amp tutorial

     
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