Buju's Innovations Mods Electronics Guides Software

Battery Desulfator

12 volt desulfator that I have built using the circuit schematic from frontiersprings.com,
Although I probably do not have the right coils , it still works , when its connected it makes a buzzing sound, I have seen up to 50 volts being generated with a current draw of 30 mA.
Peak voltage measurement is taken from C6 and negative.
The big capacitor is there when I was experimenting with different coils as C4 was getting extremely hot. The Mosfet and coils do get warm hence the heat sync and cooling fan (just in case).

I am still trying it on my first battery but it has managed to bring the charge voltage up by 1 volt in 3 days. As I try more batteries I will update my results.
I used this desulfator on a used caravan battery , which is actually just a lead acid car battery , at first it would only charge up to +- 12.6 volts , after 2 months on the desulfator the battery was charging at 14.2 volts

Purchase ready made desulfators here:


  1. I like your D2, C6, for measuring peaks.
    I suggest adding a Diode across C4, to keep it from going negative, and limiting output spike.
    Leaving L1 in series with D1 and the new Diode.
    Then increasing C4, and adjusting the duty cycle,
    could increase effectiveness.
    Thanks for your D2, C6 design.

  2. i have created frontier spring desulfator. the voltage across c6 increasing with increase in length of lead. can you suggest Why this happen? also i have used 2.5mm cable as leads. with 0.5 m it was giving 29 volt peak and with 1 meter it is giving 45 volt peak.