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Battery Desulfator Circuit Explained

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Sulphation in lead acid batteries is quite common and a big problem because the process completely hampers the efficiency of the battery. Charging a lead acid battery through PWM method is said to initiate desulfation, helping recover battery efficiency to some levels.

What is Sulphation in Lead Acid Batteries

Sulphation is a process where the sulfuric acid present inside lead acid batteries react with the plates overtime to form layers of white powder like substance over the plates.



This layer deposit seriously deteriorates the chemical actions inside the battery while charging or discharging making the battery inefficient with its power delivering capabilities.

Normally this happens when the battery is not being used for long periods and the charging, discharging processes are not done very frequently.

Unfortunately there's no effective way of tackling this problem, however it has been researched that the jammed sulphur deposits over an effected battery may be broken down to some extent by subjecting the battery to high current bursts while charging it.

These high current charging pulses should be well optimized through some control circuit and should be diagnosed carefully while implementing the process.

Using PWM

Implementing the method through PWM controlled circuit is probably the best way of doing it.

Here's an excerpt from wikipedia, which says,

" Desulfation is achieved by high current pulses produced between the terminals of the battery. This technique, also called pulse conditioning, breaks down the sulfate crystals that are formed on the battery plates.[16] Short high current pulses tend to work best. Electronic circuits are used to regulate the pulses of different widths and frequency of high current pulses. These can also be used to automate the process since it takes a long period of time to desulfate a battery fully."

The circuit of a PWM battery charger discussed here can be considered as the best design for carrying out the above desulfation process.

How the Circuit Functions

The IC 555 is configured and used in its standard PWM control mode.

The output from the IC is appropriately amplified through a couple transistors so that it is able to deliver the said high current pulses to the battery which needs to be desulfated.

The PWM control may be set at low "mark" ratio for implementing a desulfation process.

Conversely if the circuit is intended to be used for charging normal batteries, the PWM control may be adjusted for generating pulses with equal mark/space ratios or as per the desired specs.

The controlling of the PWM will solely depend on an individuals personal preference, so should be done correctly as per the battery manufacturers instructions.

Failing to follow the correct procedures may lead to fatal accidents with the battery, due to a possible explosion of the battery.

An input current level equal to the battery AH level may be chosen initially, and reduced gradually if a positive response is detected from the battery.

 

 

UPDATE:

A much simpler yet effective battery desulfator circuit can be built using only a transformer and a bridge rectifier

Filed Under: PWM

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Comments

  1. hello sir Swag .. is the circuit above whether it can be connected with car alternator with 60 Ah battery and if required fuse. thanks (sorry I use google translation 😁)

    Reply

  2. Hi Mr. Swag,
    Thanks for the reply. I used the 1n5408 diodes in series. Would I measure the current at the output of the Mosfet or the output from the diodes?

    Reply

    • Hi Peter, you can connect the meter in series with the positive supply line …anywhere…. the current must pass through the meter, that’s the requirement.

      Reply

  3. Hi Mr Swag,
    I have now built the circuit with the diodes in series, but find that the diodes get very hot after about 10 minutes. The Ic and mosfet however do not. Is this normal?
    I have checked for solder bridges and found none. Input to the diodes is 20vdc and to battery pos 15.2 VDC. Output from the mosfet drain is 12.4VDC. Any help will be appreciated.

    Reply

    • Hi Peter, which diodes did you use? check the current consumption during the charging with a series ammeter and make sure to use diodes that is rated 2 times more than this measured current consumption

      Reply

  4. Hi Mr. Swag,
    Hopefully the last question. Can I use a 7815 voltage regulator instead of the diodes? What would be advantages /disadvantages.

    Many thanks

    Reply

  5. Hi Mr. Swagatam, thanks for the very good information all over the site. I have an AC to 24v DC transformer and would like to know how to get the voltage down to 15v and can I then use that? Your help is much appreciated.

    Reply

  6. Good day sir i have built this circuit and work fine for me but but i observe the the following

    1. Initially when i Apple gate voltage to the mosfet there was an output which is equal to 14 to 15v because my transformer is a 12v transformer which i use in charging my battery and it charge fine and if remove the gate voltage there is no output which i think is normal and in this case my heatsink was a little bits warn because i use 4 mosfet in parallel which is ok to me

    2. After sometimes i observe that even when there is no gate voltage infact and i remove the 555timer i stil have an output to charge my battery and if connect to battery it still charge but the heatsink totally cold meaning the mosfet is not working but the battery is charging. Is this normal if not

    Please i want know what could be the cause and how to correct it

    Thanks

    Reply

    • Faith,

      I think you are not able see my replies because you are not pressing the "load more" button….unless you do this you won't be able to see the hidden replies.

      your second question is very strange, and It can be difficult for me to figure out the solution until I check the circuit practically…

      Reply

  8. Sir this what i observe i noticed that even when there is no gate voltage to the mosfet the battery is still charging i went as far removing the 555timer to confirm this and notice the battery was charging please what could be the cause and how to correct it thanks

    Reply

    • Faith, I think your mosfet is already burnt, or was originally faulty….instead you can try a TIP35 BJT, because BJTs are normally more rugged than mosfets and do not get burnt mysteriously…

      Reply

    • thanks Faith, you can use the following circuit for the cut off

      ttp://www.homemade-circuits.com/2011/12/self-regulating-lead-acid-battery.html

      Reply

  11. Thank u for the reply

    Ok can connect mosfet in parallel so that the current can be shared among them.

    secondly the circuit seem not to have charge control which means one needs to monitor the battery so that it dont get over charge if that be the case how can i add a cut of can i use this circuit

    https://homemade-circuits.com/2013/03/automatic-lead-acid-battery-charger.html?m=1 from this your post

    Again is the mosfet N-channel or p-channel

    If N-channel is it the drain that gose to the negative of the battery? While source to ground

    Reply

  12. Sir I'm really proud of you for ur good works and quik response you are one in a million. Sir about the above circuit can it be use to charge a 12v@600AH and if yes what modifications should i do. secondly the circuit seem not to have charge control which means one needs to monitor the so that it dont get over charge if that be the case how can i add a cut of can i use this circuit https://homemade-circuits.com/2013/03/automatic-lead-acid-battery-charger.html?m=1 from this your post if yes how i attached ithttps://homemade-circuits.com/2013/03/automatic-lead-acid-battery-charger.html?m=1

    Reply

    • Thank you Faith,

      you can use the above circuit for charging any desired battery, through appropriate modifications in the mosfet value.

      for your application you will need to replace the existing mosfet with a 100amp rated moefet…

      Reply

  14. Hi swagatam please i need your help i have a 12v battery@200A and they are 4 in number connected in parallel and i want to make a charger for it, a charger that provide at least 80A for the battery connected in parallel please can you give me pulse width charger circuit with cut off that can handle such high current thanks

    Reply

  15. can i use irf640 instead of irf540…..or is it work without toroid coils which are arranged in order to make hi pluses.. that is 1000uH and 200uH

    Reply

    • IC 555 will produce a voltage that's exactly equal to the supply voltage, so in the above case the output will be 15V at pin3…not an issue for the mosfet.

      Reply

  17. hi mr swagatam,i hope you are good
    i suggest to add a simple mosfet driver using a transistor cause 555 output voltage is weak and thus will overheat the mosfet,i tried before to connect 555 output to mosfet gate with a resistor and mosfet gets hot.

    Reply

    • Hi Hisham, I am good thanks,

      555 IC has an output that's more powerful than most ICs, however mosfets never require a powerful signal to operate, they just need a voltage above 9V for operating optimally.

      You can try reducing the gate resistor to 10 ohms and check the response….or may be the load you have connected could be above the mosfet range

      Reply

  18. Interesting circuit. I had a thought, perhaps this could be combined with adding a very small (<3ml) of acid to each cell technique for unmucking dead SLAs typically run to death in UPSs.
    If they are at 0.0V I doubt any technique will work but its the ones which have good voltage but next to no capacity that could be salvageable.

    Reply

  20. which simulator i can use to make this circuit and can have a dead battery in it for charging?
    if you plz don't mind…can you plz send me the whole process from the begining till the battery desulphation.. what all the pins are doing … plz .. i will be gratefull to you.

    Reply

  21. Good day to you sir.
    Thank you for sharing all the great work.
    A few questions about this circuit :
    1. What is the 5k POT for ? & how to adjust it ?
    2. Does the IRF 540 need a heat sink ?
    3. The negative of charger is directly connected to IC Pin #1 ?
    4. How to connect a LED to this circuit, that illuminate when connect to battery ?
    5. Any harm if connect to the battery permanently ?
    Thanks a lot in advance .

    Reply

    • Good day Alaa,

      1) 5K is for playing with the output pulse width, which might in turn help to implement a optimal desulfating effect….it could be a matter of some trial and error and dependant on the connected battery condition. however it's not so crucial, you can keep it at the center to begin with

      2) Normally it shouldn't require a heatsink, however you can test it practically by touching it, to be on a safer side..

      3) yes the negative of the charger needs toeb connected to the pin#1 line of the IC

      4) charging indication might not be possible, however an ammeter may be connected in series with the battery positive to get a direct reading regarding the batt response to the charging procedure.

      5) yes if the battery begins responding and desulfating…an ammeter can be used for monitoring the same as explained in the above point

      Reply

  22. Swagatam,

    I found an interesting video where electrons are made to flow from -ve side of battery to breakdown the hardened sulphate crystals.

    https://www.youtube.com/watch?v=AemT-IgLvS4

    Now, I have an idea and you could tell me if it works.

    Why not short the positive and negative terminals of the battery directly for a brief time, say 10ms or even 5ms? This would generate high amperes of current through the -ve terminal. This can be performed every 30sec until the grey matter(sulphated crystals) breaks down.

    This i think can be implemented using arduino board with simple programming to turn an output pin on for 10ms which turns the relay on for that amount of time.

    Would this work?

    Thanks
    Sachin

    Reply

    • Thanks Sachin,

      shorting would be advisable only if the battery has sufficient charge on it, unless it's charged fully, shorting won't induce any effect on the plates.

      The pulse charger explained in the above article is the ultimate way of dealing with this mess, if the battery responds and wakes up to the pulsed charging only then the shorting of the terminals can be tried, however as shown in the video a high amp resistive load would be more appropriate than shorting since here we don't have to worry about the delay period in ms

      Reply

  23. Sir, I'm planning to add this circuit on my existing 72v ebike charger. It has 6 pcs.12v 20ah battery connected in series. Would it be possible? What ic regulator should I use for LM555's supply voltage? And what mosfet would you recommend?

    Reply

  24. Hi Swagatam… how will i connect the PWM LED indicator to this circuit? what changes will it be?

    MikeL

    Reply

    • Hi Mikel,

      you can connect an LED across pin3 and ground with a series 1K resistor but it will appear continuously glowing due to high frequency pulses from the IC

      Reply

    • Hi Swagatam,

      i already tested the circuit in 7Ah battery.. i think it is working but i dont know the sulfation effect if it is working. the battery is charging good. by the way i change the 1nF (102) with 1uF (105), 100k pot. the supply is 15v. is it okey to use IRFZ44n for 100Ah battery?

      thanks for this circuit you shared… more power to your good work.

      God Bless!

      MikeL

      Reply

    • Thanks Mikel,

      changing 1nF to 1uF will reduce the frequency or the pulse rate, but that will not affect the results, so it's OK.

      the mosfet and the supply voltage are also OK, but the current input must be well over 20 amps for desulfating a 100AH battery, so make sure the supply current is at this level.

      Reply

  29. Hi,

    I started building your old circuit and only realized you have changed them ,but I have bought parts for the old diagram,so can I build the circuit without the inductor with the TIP122 ,or should I Change it IRF540.

    Reply

    • Hi, I changed the circuit a long time ago may be a half year ago, it's strange you are building it now.

      I would recommend you to make the above shown design instead of the earlier one since adding a coil will not make much of a difference.

      Reply

  30. Hi Mr. Swagatam, newbee here.
    So I've finished assembling the circuit, how to tell that it's working before I start attaching it to the battery? I mean is there some type of indication there or do i've to measure anything first?
    thank you.

    Reply

    • Hi Imanul,

      There's no circuit which can guarantee a perfect desulfation in dead batteries, so you can only hope that this circuit produces the intended results as it's designed as per the standard recommended specifications.

      Use the circuit for about 4 hours and then check the battery with an appropriate load, if the charge sustains for an appreciable amount of time you can assume it to be revived, otherwise you may repeat the procedure with some change in the PWM frequency and/or the input current to the circuit and check the response in a similar manner.

      Reply

    • …please change the 1n caapcitor with a 10uF capacitor.

      connect an LEd across pin3 and ground via a 1K resistor.

      When switched ON this LED must flash rapidly indicating a proper functioning of the circuit, changing the pot would change the flash rate on this LEd

      you can keep the new capacitor connected and use the circuit for the required purpose, it won't make any difference in the performance.

      Reply

  33. hi
    I just realise in the circuit there is no ground to the circuit?
    if we use power supply to connect to this circuit the plus 15V pole goes to the battery and the circuit where then the negative pole goes?
    I know if I use coil and transistor I have to connect the negative pole to emitter but on mos fet not sure looks like this one joint missing from the circuit
    could you please correct me if I am wrong?

    Reply

    • So Avenger is saying that there is no coming back from hard crystalline PbSO4 .
      OUCH!
      One should have all batteries under full time trickle charge.

      Avenger ,…. which one of Swagatam's designs did you use for your charger?

      Carl

      Reply

  34. Lead Lead Sulfate PbSO4 is part of battery charge discharge cycle. The structural form of PbSo4 makes the difference. While amorphous PbSo4 is reversible while hard crystalline PbSO4 is irreversible and inactive. Shallow cycle batteries never have to be discharged under 12.5 volts. If this happens an immediate charge will consume and transform PbSO4 in to Pb, H2O, PbO2 and H2So4. If let staying there for sometime the PbSO4 crystallize and turns inactive. To make a long story short if battery isn’t in use immediately use Float charging with a battery trickle. Harbor freight tools sell a battery trickle (Floater) for $9.99, which I bought on sale for $6.0. The manufacturer 13.2Volts was only a promise, but replacing VR1 with a 100-Ohm trim pot, I can adjust the voltage from 12.6V to 14.25V. I set it at 13.25V but this is only the first aid. What you need is EQUALIZE the BATTERY; this can be done at 14.5V for some hours. During this process the strong cells start boiling but the weakest cells continue charging. This can be done with a battery tender. I bought one from Wal-Mart connected to my VW Touareg and the next day the relay was chattering ON / OF non-stop. Measured Voltage a found 14.85 Volts. The electronic system of the car was fighting hard against this stupid tender. I solved the problem building up my Battery Tender with precision voltage Window 14.5V stop charging and 12.6V restart charging giving the battery a chance to rest, RELAX. Charging a discharged battery you have to deal with Bulk Charge Current Density that depends from electrode surface and is expressed on mA / Cm2. If a have to deal with an accidentally fully discharged battery I use my Automatic Smart Battery Charger, with Equalizing and reconditioning features.

    Reply

  35. Hello Swagatam,

    I would like to build a hi/lo adjustable relay/contactor.
    Say ….12v on 13.5 off
    I could then put it in series with any charger.
    It would be great for maintenance and prevent over charging.

    A variant of this could also kick in a discharge cycle.
    This would be good for desulfating.

    Do you have a design lik this?

    Yours
    Carl

    Reply

  36. Hi Swagatam

    Since I was focusing only on the mosfet so I didn't gave you the details of the other sections.

    As mentioned earlier, one cycle consists of mainly 3 steps + 1 step to monitor battery voltage. Each step is controlled by a 555 and another 555 is controlling all these 4 ICs (the entire cycle). If you want to have a look at the circuit, here it is.

    https://dl.dropboxusercontent.com/u/20969135/Desulfator%204-stage.gif

    I am sorry, that is maximum available resolution of the picture.

    Now, I repeat my question in other way. If the mosfet can be driven directly by the 555, why the author deployed 0.8A transistors to drive the mosfet. You can find them at the top-right corner. I haven't linked the website as per your general instruction however, if you want to see the circuit description I can send you the link.

    Reply

    • Hi Abu-afss,

      It could be for allowing the mosfet to conduct and restrict correctly, especially the use of the push-pull (PNP/NPN) stage which ensures safe charge/discharge of the internal cap of the mosfet, because as we all know how sensitive these mosfets can be at times.

      Reply

  37. Hi Swagatam 🙂

    One complete cycle includes 3 steps:

    1) 15 sec pulse charging
    2) 1 sec delay for settling
    3) 100ms shorting battery terminals

    I am just curious about the driving of the mosfet as I asked in my previous post.

    Reply

    • Hi Abu-Hafss 🙂 how are these three steps implemented because i can see only one active input from the IC 555.

      I wanted to know the relevance of the transistor stages for answering your question correctly.

      Normally we know that a mosfet gate can be integrated with any IC output may it be a 555, a cmos or a opamp, as long as the voltage is below 15V

      Reply

  39. Hi Swagatam

    I have read some of above posts talking about an inductor L1. Where is that inductor, I can't see it in the circuit or any reference in your article?

    By the way, I am working on a trickle charge desulfator. I am considering to integrate a circuit to measure battery's internal resistance (BIR). There are a few BIR measuring circuits on the net but, they need to take occasional measurement manually. Here are two of them:

    https://dl.dropboxusercontent.com/u/20969135/internal-resistance-tester-for-batteries-2.jpg
    https://dl.dropboxusercontent.com/u/20969135/accutest.jpg

    My idea is to have three-LED indication……..the red LED to indicate high resistance, yellow to indicate medium and green for very low resistance. The BIR circuit will operate in parallel with the desulfator circuit. The illumination of the green LED would indicate that the battery has been desulfated, now it is ready to use.

    A relay could be used to connect the BIR circuit to the battery periodically to check the status. A latch can be deployed to keep the indicator LED on but, I just cannot sort out how to get the output on LED as the output is just 5-50mV.

    Can you please help me in this regard? If required, I can send you the links of the sites to have the description of those circuits.

    Reply

  41. Thanks again Swagatam, will update the thread with my results.
    btw, I read somewhere (maybe here..) that the high current pulse may burn out shorted cells restoring even batteries that are considered unrepairable.

    Reply

  42. Hi Swagatam
    Finally have parts to make the pwm but looking for a hi current supply.
    It occurred to me that lead acid batteries will not sink as much current as it starts to get full. Does the circuit take this into consideration ?
    When the transistor is on, is it essentially grounding the battery ?
    When it is off, is there any ringing without an inductor ?

    Sean

    Reply

    • Hi Sean,

      If the voltage is set at some higher level then that will force the battery to sink the current which in turn will hopefully initiate the desulfation process.

      Here you can try with a 15V DC, current may be equal to the AH level of the battery and the pot set to provide short pulses.

      When the transistor is ON, it connects the negative of the battery to the negative of the power supply completing the circuit for the battery so that it receives the required charging pulse.

      No, there won't be any ringing effect due to the absence of an inductor.

      Reply

    • hi Swagatam,
      Thanks again for your reply. How do I limit the current ?
      I planned on using an old server power supply or rewinding the secondary of a microwave transformer. Won't the circuit try to pull all the current it can unless its limited ?
      Sean

      Reply

    • Hi Sean,

      The circuit will not draw anything above 5mA, as long as the voltage does not exceed 15/16V mark, above this anyway the IC555 would get damaged, so I don't think any current control for the circuit would be required.

      Reply

    • Hi Swagatam, I think you mis-understood my question.
      With your circuit you recommend limiting the current to the battery initially to 1C. so if I have a 40AH battery, I should limit the pulse current to 40AH. I was asking how I could do this since I don't have a power supply with a current limit. I am thinking of making a power supply by stepping down 240VAC to 15VAC and rectifying it. But this will not be limited. Is there a clever way to control the max current the battery draws ?

      Reply

    • Hi Sean,

      You can select a transformer rated at around 20 to 30 amps, that will itself take care of the current…actually the current is not a critical value, anything higher than the normal charging method can be employed, and expected to work here.

      Reply

  43. Thanks for your clarification. I was curious about the use of the inductor (i.e. collapsing magnetic field/pulse, etc).
    Anyhow, I will try this circuit out as its simple enough to make. I would like to try to revive some large capacity (100AH) NiMh batteries I have pulsing with high current. I am hoping the technique will lower the internal resistance of the batteries even though the chemistry is different (i.e. they don't sulphate).

    Reply

  44. @Swagatam
    Nice circuit I look forward to trying it out.
    Just one question, Where should the negative from the power supply go?
    Thank You

    Reply

  47. Thanks Swagat,
    Tryed smthing diffrnt with the stablizer that i must share wid u.
    There are 5 taps in auto transformer, 1st n 3rd tap has been used as input with a relay control and rest for output wid 2 more relays.
    I inspected the 1st relay status at power on, it was making 1st tap as as input for 1 sec then change it to 3rd tap as input, so there was high volt at power on.
    I interchanged 1st and 3rd tap input with relay.
    Now its working good .

    Reply

  48. Thanks Swagat,
    sorry for one more problem,
    I inspected the stablizer, it has 24 volts relays, so i need to operate the "delay on" circuit on 24 volts instead 12 volts.
    What modification i need?
    Thanks

    Reply

  50. Hi Swagatam, I have installed automatic voltage stabliser for home supply,
    the only problem is, when it starts, initialy it supply high volts(300 ) for less den 1 sec. den it functions well..
    Pls let me know what is the problem n how can i fix it..

    Reply

  52. Swagatam:

    Swagatam:

    Thanks for your reply and recommendation. If working at 555 with 5 volts regulated from 7805, the oscillation frequency is not affected?

    Are pleased to greet and congratulate again the excellent circuits published.

    Reply

  53. Swagatam:
    Excellent circuit, I'm about to try arm. I'd appreciate if you tell me regularly cnveniente a zener and 100 ohm resistor voltage to the 555 and ensure it does not overheat.

    Thank you for your attention

    Reply

  54. Good day, Swagatam,

    I didn't get nF capacitors (not available at the shop I went to), I bought a 1 microF and a 100 microF. If I substitute these into the circuit, how will it affect the output?

    Thanks,
    Satyam.

    Reply

    • Good day Satyam,

      The circuit needs to be operated with high frequency so a 1uF or 100uF will not work.

      1nf = 0.1uF, so can try other closer values like 0.22uF etc. or any value between 0.01uF to 0.1uF will also do.

      Reply

    • Good day,

      Thanks for your quick response. I've built the circuit with the components that I described, however I'll keep looking for the correct capacitors. (I got some surface-mounted caps yesterday, but destroyed them trying to install them.)

      I suspected that my frequency would be affected. Using f= 1/(0.693 x C x (R1 + 2R2)), the frequency of my circuit would be somewhere around 300 Hz, whereas your design is for 300 kHz. Does that sound about right?

      At any rate, I'm using it on a number of car batteries where I suspect sulphation. Will come back & update when I replace the caps, or with results.

      Best regards.

      Reply

  55. Dear Swagat

    "An input current level equal to the battery AH level may be chosen initially, and reduced gradually if a positive response is detected from the battery."

    You mean if we are desulfating a 100 AH battery you need 15V 100AH?.

    Pranav BM

    Reply

    • Dear Pranav,

      It's my guess only, it will depend on the condition of the battery, if you can arrange for 100amps then surely you can try it with very short pulses for a 100ah battery….again I am just assuming the current magnitude to be suitable.

      Reply

  56. hi swagat, i thin there is some thing missing in the circuit, the inductor and couple of the commentors where mentioning about 100k resistor which i do not find in the ciruit, is this diagram correct?

    Pranav BM

    Reply

  57. Thank u sir,
    Could u please let me know the way to design a battery charger using your charger concept to charge the Generator Battery.
    I mean i need to hook the charger permanently of the battery.
    Could u please reply me below email. chandanapsd@yaho.com
    Thanks advance…
    Good Luck and Highly appreciate your knowledge sharing.

    Reply

  58. hello sir… i have 12v 7Ah sla battery. what must be the input current for the above circuit to desulfation?

    Reply

    • As mentioned in the article, the current should be considerably high, you should use a 40 amp transformer may be initially for testing.

      Otherwise the sulfation will not initiate.

      Reply

  61. Hello Sir,

    I make this circuit and checked all the connections twice. It looks everything
    is fine, but I don't notice any change in battery after connected for about 10 hours.
    My battery is of 12v, 50 Amp.

    How long it will take to d-sulfate it ?

    Thanks.
    Rashid

    Reply

    • Hello Rashid,

      What's your AH and how much current are you using in the circuit power supply???

      Though there's no confirmed value, the current from the mosfet should be almost equal to the AH of the battery, and the pot should be adjusted to produce short bursts of output.

      Reply

    • you will have to experiment it by using different types of inductors, start with a 22swg wire wound over 6 inches ferrite rod having diameter of 1 cm, put around 50 turns initially and then vary it by increasing or decreasing the turns. check the output voltages across the coil without load with different number of turns..

      Reply

    • hi, swagatam, i would like to confirm if the disulfator circuit uses an inductor coil since i don't see any in the above circuit. i'm just confused. thanks

      Reply

    • The inductor has been removed in the present design because according to me it's not required. A desulfation process can be possibly initiated by applying high current short pulses to the battery, which can be achieved by using a high current transformer, probably equal to the battery AH level.

      Reply

  66. Swagatam,I am absolutely sure your circuit works.

    I am trying to think of a way to observe and fine tune it for optimum.

    I'm thinking if I took a badly sulfated cell out of a battery and put it into a glass or clear plastic case along with the electrolyte, I might be able to see the action.

    What do you or your readers think?
    It's great to have a place to ask the question.

    Thanks

    Carl

    Reply

  67. Do you have any ideas on how to observe or test/measure the effects on the battery when searching for an optimum setting?

    This circuit of yours is suitable for experimentation as the 555 is so adjustable.

    It might be that having the battery in a clear case and observing the effects visually might be helpful.
    One would have to keep an eye on temp and gas production.(don't want to boil it away)

    Your thoughts…..

    Thanks for this
    Carl

    Reply

    • perhaps the only way to test this is to connect a virtually unresponsive battery to the circuit and set the pot to reasonably high levels, if the battery starts to accept the charge after a period of time, would prove the working the circuit…..however it's just my assumption…

      Reply

    • Hi Carl,

      As far as I know, the voltage should be slightly high than normal, but the current should be sufficiently high, and in the form of pulses.

      Regards.

      Reply

  70. Greetings everyone,
    i saw this circuit and i think it is extremely practical, i'll try to do it, because i had a dead battery on my bike. but looking at the scheme and searching i don't see what is the value and type of the L1 inductor. Could you specify, please.
    also i'll try to use a microcontroller to do the pwm. I think it just have to be at the same ground, right?

    Reply

  72. thank you
    i want to desulfate a 200ah deep cycle bat. what kind of mosfet can i use ?
    i experiment with a lot of desulfetors but noone can do the job efectively
    please can you desigh a lifepo4 pcm circuit with balance i think thatis the future of the energy storage problem.
    keep on the good work
    thank you

    Reply

    • hello, you will have to experiment with it until you get around 18V across it…the thickness of the wire should be adequately large for supporting the battery charging current, same would be true for the transistor…..alternatively, it may be replaced with a mosfet.

      Reply

  74. sir .. in above circuit …..is resistor 100k variable? how we set its value….
    what is given input voltage?
    sir i have simulated this circuit on proteus bt there is no output…. plz help me. how we will give voltage and type of Resistor 100k and about its value selection… and input voltage/…
    i shall be very thankful to u

    Reply

  75. HI
    Sir ….. i am interested in making desulfator,,,, can u plz help me in making it,,,, i am very curious in making a new innovation in it…. plz give me the basic concept of its designing,,, i shall be very thankful to you,,,,

    Reply

  77. yes,you are right.Even i was wondering where will power supply come from,,,Could you tell me how to construct a trickle charger.Im designing the other pulser,,like Ron Ingrahan circuit,it appears i need a separate charger together with pulser in parrallel.Your circuit seems to be quite precise.

    Reply

    • Trickle charging is a process in which the battery is not allowed to discharge if its not being used for a longer period of time, it's an almost zero current charging at full charged voltage level.

      Though It will depend on the AH of the battery, typically you can connect a 10K resistor in series with a suitable charger for keeping any battery trickle charged.

      Reply

  81. in PWM, you need to send High voltage or Current, if we set it to 14 out put will it help in removing the sulfur form the plate. kindly let us know how it works, can we design a better circuit to indicate its working. i also suggest to include a fuse for safety for polarity and other effects

    Reply

  82. Hi swagatam,
    i bought the parts today and will start making this by next holiday. but i don't want to explode my battery. So please explain how much i turn the 100k pot?

    Reply

    • Hi, I don't see any 100k trimmer in your circuit? I have a 100Ah battery. Do I have to inject 50 amps to it? Best regards.

      Reply

    • please ignore these initial comments, the diagram has been modified and updated differently, so these comments have no relevance with the present diagram.

      Reply

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