AC TO DC /Rectifier IC 555 projects lead acid battery

Recover Lead Acid Battery | IC555 Battery desulfator

Hello People, Sometimes our batteries in go-carts, inverters, kids buggy toys, emergency lights, etc after a long period of inactivity resist to full charge. They may also stop charging completely or their supply quality degrades to a greater extent. This is due to battery sulfation. In this article, we will discuss more about the battery sulfation and How to recover Lead acid battery from sulfation. I have also explained a battery desulfator circuit. I have mentioned a simpler circuit to charge a sulfated battery. Let’s start with our topic, ” RECOVER LEAD ACID BATTERY “, ” Battery de-sulfation circuit “.

What is Sulfation?

Sulfation is a state occurs when a battery is deprived of a full charge, a layer of lead phosphate occurs crystals around the electrodes and remains on battery plates. Batteries create sulfation each time they are used (discharged – recharged).  If they are overcharged or undercharged or are discharged for a long time, they will rapidly develop sulfate. Even if a battery is stored fully charged, sulfate will form unless a desulfation battery charger is used.

Lead and lead dioxide, the active materials on the battery’s plates, react with sulfuric acid in the electrolyte to form lead sulfate. The lead sulfate first forms in a finely divided, amorphous state and easily reverts to lead, lead dioxide, and sulfuric acid when the battery recharges.

Using or storing batteries in temperatures above 75°F accelerates the rate of self-discharge and increases battery sulfation of battery.

What is desulfation? How do battery desulfation circuits recover lead acid battery?

Desulfation is a reversal process to remove sulfation from a dead or sulfated battery. Desulfation is to restore a battery by breaking and removing the lead sulfates crystals from the battery electrodes, either fully or partially.Desulfation either restores the battery to it’s full potential or upto 60-70% sometimes. Perhaps, there is no such specific percentages, but, though it works very well. Sometimes fully and sometimes almost.

Battery desulfation can be achieved by using battery desulfator circuits. This involves applying constant high current pulses to the battery terminals. This is called the battery conditioning method. It breaks the sulfate crystals which are formed on the battery plates. This method is probably very good and one of the best.

Steps to follow:-

  • STEP1: Take the battery and note down its initial voltage.
  • STEP2 Remove its case if its an SLA(Seale Lead Acid )battery and open the vent caps.
  • STEP 3:After you have removed the case and vent caps are off now. Use a dropper or injection syringe and fill each cell with distilled water (De-ionized water). (Remember not to fill it with tap water otherwise it will damage the battery’s electrodes.).
  • STEP 4:Wait till each tube gets the water mixed with dry acid and bubbles gets down.
  • STEP5: Charge the battery with a battery de-sulfate charger circuit for some 5 hours then check the voltage constantly using a DMM.
  • Remember that the battery’s connecting time will be according to the battery size(ah), charger output power & how long it takes for the battery to come at its healthy output behavior.

IC555 Battery Desulfator Circuit

Recover lead acid battery IC555 battery desulfator


  • IC555 – 1pc
  • R1 10K
  • R2 470R
  • C1 1uf Poly capacitor 63v
  • C2 10nf
  • Q1 IRF540N or IRFP260N for batteries bigger than 26 ah
  • D1 Use any 6amp Rectifier diode ( for eg. 6A10)
  • Transformer 18v or 24v 5amp-8amp
  • Rectifier circuit with 6a rectifier diodes
  • LM338


The Circuit above is an effective and simple battery desulfator circuit. The circuit is above is a high current IC555 pulse generator with a higher frequency. For the above desulfator circuit, we need to make use of a suitable rectifier and transformer with an adjustable voltage PSU circuit. So, that we could get the higher current and desired voltage output to feed into the desulfator circuit.

For Higher current, I suggest a powerful transformer with a current up to 5 amp and 6A rectifier diodes. To adjust the output voltage and provide a higher amp output to the desulfator circuit, I suggest using the LM338 High amp variable power supply circuit. LM338 has the potential to go at a range 2A- 5amp, with an output voltage range from 2 to 35V dc. Input must be always 2 volts more than the required output voltage like to get 15v, you must input 18v or can be higher.

The High current 15 v input is then fed to the desulfator circuit which then generates pulsed output at a higher current & a frequency at 130Hz. 130 hz high current 2-5amp input can effectively remove and zap out the lead sulfates that was hardening over the battery plates.

This then enable the electrodes to react with the acid and also to work efficiently.

Before connecting to desulfator circuit, don’t forget to fill up each battery cells with the distilled water till the top(but not overflow).

Charge at least 6 hours ( 6-12ah batteries) then check the voltage if it’s above 13.5v. Also, put an ammeter in series with the charger and the batteries positive terminal.

Also, put an ammeter in series with the charger and the batteries positive terminal. Observe it if the current is increasing and is going up to the initial rated current of the battery then it’s a positive response.


  • Remember, It’s Not for kids, Only experienced hobbyists or professionals do this.
  • Make sure you wear proper glasses or something to protect your eyes and face when filling de-ionized water.
  • Don’t keep your face above the battery while filling it with distilled water.
  • Fix the battery vent caps and covering perfectly after filling.
  • Charge at least 6 hours ( 6-12ah batteries) then check the voltage if it’s above 13.5v. Also, put an ammeter in series with the charger and the batteries positive terminal. Observe it if the current is increasing and is going up to the initial rated current of the battery then it’s a positive response.
  • Keep away don’t be too closer to the battery as no one knows and there is no specific way to tell if it’s really a bad battery, you should not get any fatal injuries if something you did wrong.

I hope you guys liked it. I HAVE ADDED A VIDEO LINK FOR IT TO MAKE YOU UNDERSTAND MORE CLEARLY. You can watch the video by clicking here. The circuit in the video is different, but I prefer this one over the one shown in the video. THANK YOU FOR WATCHING.

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Hello everyone, I am Abhishek Sharma. I am an Engineer, a passionate blogger, an Electronics circuit designer, and the Founder of Electroinvention. I love making cool electronics circuits and gadgets. I also do SEO(Search Engine Optimization) work and also, I am a student of Computer Science.

7 Replies to “Recover Lead Acid Battery | IC555 Battery desulfator

    1. Hi, Adolph, thanks for visiting, the distilled water is used to re energize the dried acid, acid doesn’t get weak by water. It increases and dilutes. But any battery can’t be fully desulphated. This method only recovers the battery 50-70%.

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