Lead Acid (SLA) battery desulphation.

Discussion in 'Power Electronics' started by recklessrog, Jan 21, 2018.

  1. recklessrog

    Thread Starter Well-Known Member

    May 23, 2013
    825
    287
    It would be ok to build the pulse generator and the buffer chip on a bread board, but due to the high current pulses, not the inductor, Mosfet, and output diode. Also note that the circuit only use half of the 4049, do not leave the unused inputs unconnected or strange things can happen. All inputs must go somewhere, best to connect them to the negative of the supply. you can leave the unused outputs floating.
    most any N channel power mosfet works in that circuit as long as it is rated at 200 volts/15 amps or greater. Mount it on a suitable heatsink.
    When you don't have a load connected, depending on the inductor you use, you can have very high voltage spikes across the Mosfet.
    I found that the inductor is also not critical, anything from 200 to 400 micro Henries will work ok, but it needs to have a reasonably large core and thick enough wire (24swg minimum) to handle the current of the pulses which can be up to 40 amps. Look at the picture of the one he used.
    All the ones I had success with were reclaimed from scrap plasma tv power supplies as were the Mosfets and shottky diodes.
     
  2. racmaster

    New Member

    Feb 13, 2018
    27
    2
    hi guys, are you still there? anything new with the testings?
     
  3. racmaster

    New Member

    Feb 13, 2018
    27
    2
    is the thread dead now?
     
  4. mientrung dichthuat

    New Member

    May 19, 2018
    1
    0
    My thoughts exactly, my off the shelf desulfators are actually discharging the battery (hence creating more sulfate overall) by running.

    That said, there is one hypothesis that what desulfators do is not dissolve sulfate, but break down the layer of passivation between the positive grid and the sponge lead on the positive plates. I've read that the introduction of desulfators in the early 90's happened to coincide with the mass adoption of modern maintenance-free batteries using a lead/calcium alloy in the grid (which are susceptible to corrosion that gradually causes an insulating layer to form between the grid and the lead - which the pulses from the de-sulfator may be breaking down).
     
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