DIY Battery Desulfator / Charger

Battery Desulfator / Charger

First off, I’m providing this desulfator info for educational purposes only.  It does work and works damn good, but I’m not promoting that anybody build it.  I did, but I’m certified crazy when it comes to electricity, ask any of my friends….

Its a very simple capacitive battery charger made from scrap parts, but if you have little respect for electricity, or batteries for that matter, it’s best you move along to another project.

You have been warned…

I have restored many garden tractor, automobile, and SLA (sealed lead acid) batteries with the one I built.  This charger will put out HIGH voltage, approximately 150 volts DC, at a low Amperage to begin the desulfating process and come down to about 14 volts DC to finish charging the battery.

CAUTION!!  Use the charger outside of your garage or shop because a charging battery generates Hydrogen gas, some very explosive stuff, but that’s another story. Always hook up the battery leads BEFORE plugging it in, always unplug the charger BEFORE removing battery leads. Stay away from the battery while charging. Do not charge a battery while wired in the vehicle, unless you want 150 vdc smoking your voltage regulator, alternator and electronics …


capcarge1          capcarge2

I used a dual 10/25 mfd ac motor run capacitor for 1/2 or 1 amp current limiting. I used a 2 amp/200 volt bridge rectifier.  This charger will desulfate and charge any lead acid battery, 6, 12, or 24 volt.

The problem with regular battery chargers is they cannot equalize a battery or desulfate cells. Not enough electrical pressure to bust up the lead sulfate that’s insulating the cell plates.

The amperage output is limited by capacitor size @ 25 mfd per amp, i.e. 25mfd/1amp, 50mfd/2amp, 75mfd/3amp, etc.

One more suggestion, check the battery often for overheating in case there is a shorted cell.  I use a timer with mine and set it for an hour the first charge, in case I walk away and forget about it, then I step it up to 2 hours, then 3 hours, etc. until I’m comfortable that it’s taking a charge ok.

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