Does anyone have any first-hand experience with battery desulfators?
While I know that a high frequency waveform is supposed to "de-crystallize" the lead sulfate and "restore the battery", I haven't found any designers who have first-hand experience with this.....
This is my personal experience, about 40 years ago. I bought a small surplus dry-charged 6V lead acid battery made in the
40's for the war. Added acid and it was dead - so dead that even with 100V across it the current was only a few mA. So i put it across the line (120VAC with a current limiting resistor (about 100mA); took a week to come up that far. Then i rigged it with a capacitor in series and a reverse polarity protection diode across the battery and used that scheme to pump more cycling current thru the battery and charge it at the same time. Stopped that when the AC current was near an amp and changed again. Used a 12V filament xfmr as source, current limiting resistor and same reverse polarity protection diode across the battery, until the AC current was 3 amps or so. From then on, i used a resistor to discharge it to 10V, and a standard charger to bring it back up; 5 or 6 times. Short circuit current from this dinky "motorcycle" battery was over
100 amps when i got done rejuvenating it. Took a few months overall.
"Sulphation" is the term and the problem. It must be broken up, and the smaller the particles that result, the better the results will be. Keep the cycling current low, and AC is OK when that current is far less than the rating (C/1000 or less i would say). When the current gets in the region of C/200 or so, go with charge/discharge and no reverse current (hence that protection diode). I do not think that the waveform matters much.
I have not looked at the references given by others in this thread.
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