120 VDC Power Supply

Discussion in 'General Electronics Chat' started by kcarring, Feb 1, 2011.

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  1. kcarring

    Thread Starter Member

    Jan 22, 2011
    I have been looking for a good learning resource to build a non-variable power supply 120AC - 120VDC. I found one similar thread, but I didn't want to step on his project, so I started this thread.

    The objective is to power an electrolyser that is connected to my solar panel system. When my battery bank is full, and have available solar, I use the electrolyser to produce fuel that augments my combustion chamber in a methane furnace fed from a digestor. The hydrogen helps clean up the emissions pretty good.

    It all works fine.. but it is not usuable at all on AC, because it runs on stepup transformation 12VDC -120VDC.

    I wish to get it running on 120VDC as supplied by AC. I do not wish to have regulation maybe just some capacitive smoothing. The pulsing effect leftover from the 60Hz seems to help not hinder, we are not talking about sensitive device here. Peaks and variances do not harm it in any way.

    I also have a little AC power supply that allows me to experiment with low AC first, an AC step down transformer, with multiple taps.

    The Diode Bridge I have right now is marked:

    CHINA 031C

    I think this is the datasheet.

    I do not want to go down the route of 120AC to 120VDC transformers. Too much loss, I'm told, in the form of heat, not too mention the cost and weight of design. If for example I end up with 118 or 119 VDC, in the end, that's fine too, I can remove or add a plate to the electrolyser, as needed to adjust the volts.

    I anticipate the draw to be less than 10a, but I haven't done the surface area calculations to find the Faraday theoretical numbers, but I could.

    My thoughts are that I should experiment with this diode bridge under low voltages and get a feel for it. I also have some excellent large heat sinks from a PA amplifier that will be overkill, for sure. They are huge.

    More than anything I need a pointer to some circuits to see how to understand this bridge and how to connect it up, and under what voltages should I do experimentation as to be safe.

    The end result will have of course switching, and overload protection, although the electrolyser has an internal draw adjusted by the NaOH concetration and even during thermal runaway after hours of use, the max draw only increase so much.

    Thanks for any remarks.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    Well then we needn't continue this any further. We do not deal with circuits that do not have galvanic isolation from the line, as the safety issues are too great.

    BTW, water electrolysis goes at significantly lower voltages. Mr. Faraday established this almost 200 years ago. The HHO people have everything wrong about the process.
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