charging a 12 volt battery from a 12 volts battery

Discussion in 'The Projects Forum' started by adeel, Feb 12, 2013.

  1. adeel

    Thread Starter Member

    Jun 28, 2008
    hello friends i want to build a charger circuit from from which i can use a battery of high AH and charge battery of small size. i search the internet world and found a circuit but before i started i want to see if this circuit is stable and reliable i want to charge battey at 10 to 100 ampare. So circuit should be able to handle that high power (100 amp max) And i should be able to controll the ampare by a volume controll . Can u plz tell be what to change in this circuit .Both batteries are of 12 volts so i think it will need a booster circuit.
  2. Evil Lurker


    Aug 25, 2011
    Not going to happen with that circuit. First, it only has a 10 amp rated diode. Second, with that small of an inductance, the circuit is going to have to be switching pretty darn fast. While I suppose the IC could in theory drive three IRF540's in parallel, honestly it really needs some more efficient mosfets, possibly a dedicated fet driver, and local pulldown circuitry to decrease the switching times or the fets (and the IC) are gonna get very very hot. You also probably should look into an optoisolator and LM358 to add in current control to the output too.
  3. adeel

    Thread Starter Member

    Jun 28, 2008
    well if i can increase the number of fetes to 20 and use high current fet like irf1405. and change the diode and incductor then this circuit will work???If u have any circuit can u plz share that with me thanks.
    Once i saw a circuit of a charger and ups APC which was using only 13 volts iron core transformer and four heat sink of FETes and using charging ic of their own company apc2020 that ups charges two batteries. but this ups has no inductor in it only FETes inside is any friend know the best way to do my work. thanks
    Last edited: Feb 12, 2013
  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
    What is AH rating of small battery? You only need about 5V from inverter and stack it on to 12V battery.
  5. Babber

    New Member

    Apr 19, 2011
    I would also use a linear pot, not a volume control. The volume control will be log and might not give you good trimming of the output voltage. Also, the pdf looks like it's set up to deliver 24V out, which I would guess would be too high for your smaller battery
  6. Brownout

    Well-Known Member

    Jan 10, 2012
    For 100 amps, L1 would need a huge iron core. The capacitors would need upgrading, thick wire to prevent losses, etc. It won't be easy or cheap. A better solution would be to make a number of these circuits and connect them in parallel. An easy solution ( what I do ) is buy an invertor and plug in a battery charger.