Capacitor or inductor for direct charging batteries from ground isolated 120vac?

Discussion in 'General Electronics Chat' started by rudyauction8, Feb 21, 2015.

  1. rudyauction8

    Thread Starter Member

    Jan 27, 2012
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    I'm trying to make a quick charger for my 36v 150ah battery pack using ether inductors or capacitors and a high current rectifier. I'll be powering it with a ground isolated 2kw generator. It'll only run for a couple minutes at a time while I monitor voltage, current and temp. Which would be better, capacitors or inductors? I've already built one successfully with induction motor run caps but it took dozens of them for an 8 amp power supply, but I'm looking for closer to 30 amps. I've also been considering a mercury vapor 400 watt ballast with the secondary coil re-wound for the lower voltage. The batteries may have up to 25 amps being drained from them while charging.
     
  2. ronv

    AAC Fanatic!

    Nov 12, 2008
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    Since your generator can only put out 16 amps at 120 volts you need something to step down the voltage so you can get more current, not just burning up the difference in heat. It would call for a really big transformer or a big switching regulator.
     
  3. rudyauction8

    Thread Starter Member

    Jan 27, 2012
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    2
    So if I re-wired a 400w ballast to put out ~40v that would be my best bet? I also have a 70 amp welder from harbor freight, it could work if I added a full wave rectifier.
     
  4. ronv

    AAC Fanatic!

    Nov 12, 2008
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    The welder might be the best bet. Do you know the voltage of it?
     
  5. rudyauction8

    Thread Starter Member

    Jan 27, 2012
    252
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    Around 35 volts AC, I could use it to charge the batteries all at once when they're really low then charge 2 to full then finish the 3rd. Also I think that the rectified output would be around 40 volts (correct me if I'm wrong, I know 120v is like 150v rectified) which would be just about right. Or I could just switch to 24v, I haven't built the battery bank yet so that wouldn't be a problem.
     
  6. ronv

    AAC Fanatic!

    Nov 12, 2008
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    You know, I think that might work. :)
     
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