Preliminary article Created: "March 6 2009"
My Latest Revision: "December 13 2011"

I REMOVED this Project because I don't consider it Practical.

CONSIDER THIS:  Desulfators that are Self powered by the battery they are desulfating, are
also Draining the battery, thus leading the way for More Sulfation.
If you add a Battery Charger to maintain the Battery, it may help to Eliminate this possibility.
But it can also interfer with the Desulfation Process.

But I find MOST PEOPLE DON'T Do this.
And the IDEAL Solution is to actually have the Desulfator, Powered by a SEPERATE POWER SOURCE.



"So I am now working on a NEW Desulfator".





This Circuit helps to Desulfate a lead acid battey.
It also gives a fair indication of the batteries Internal Resistance.

NOTE: Some Batteries can be Improved, Some NOT.
Sulfated Plates are only One of Many different battery problems.
So it all depends on whats wrong with your battery?

BEFORE you attempt to Desulfate a Lead Acid Battery,
Test Each Cell for Specific Gravity with a battery tester.
(This Isn't possible on "SLA" Batteries or "Maintance Free" Batteries.)

If just "one or two cells" are really LOW, compared to the others,
You have a "BAD Battery" and attempting to Desulfate it, WON'T Help.

In a Sulfated battery (Or an Under-Charged Battery), All Cells should read Very Equally Low.
In a Really Good Battery, All cells will be EQUIL in Specific Gravity.


This circuit produces a Pulse Current Spike to help Desulfate a battery.
Additionally, the other part of this circuit detects this Pulsed Current Spike,
"Directly At the Battery Terminals".

This signal is than amplified and gives a reading on a 200 uA Meter.
And this reading will reflect on the Internal Resistance of the battery,
So the "LOWER the meter reading the better".

Sulfation Causes Higher Internal Resistance and Internal Resistance in a Battery
Reduces its ability to drive High Current.



For 6 Volt Battery Desulfation:

Connect a 12 Volt AC Adapter (12 Volt DC Wall Wart) Between PCB Negative Rail
and Pins 4/8 of the 555.
This will not only give the Correct Drive voltage to the Mosfet,
it will also give a Trickle Charge to the battery through R4.

Also because of the 6 volt supply and assuming a 200 to 250uA meter,
I suggest Changing R8 to a 47K resistor.
If using a Less Sensitive Meter, (600uA to 1mA) it my need to be
Reduced even more To get Suitable readings on internal battery resistance.



In Theory, with "Unlimited Sensitivity", and with a "PERFECT Battery", the meter
reading would always read "ZERO".
However, This will NEVER HAPPEN on a Real Battery.

And in real life, Smaller Lead Acid or Sealed Lead Acid Batteries will have Higher
Meter Readings than Large Car Batteries.



This Desulfating Process,  "May take a LONG TIME".
This Process may be anything from a "Day or Two" for just General Battery Maintance,
and up to "Several Months for a really Bad Sulfated Battery".

And the battery MUST have a Reasonable Charge on it for this Desulfator to work.

Failing to Maintain a Charge on the battery, can be solved by connecting the battery
to a Solar Panal or a suitable DC Supply of about 14 Volts "Via a Series Resistor".
I would recommend a 10 to 20 Ohm Resistor.

This SERIES Resistor is IMPORTANT, to Prevent the "Charger's LOW IMPEDANCE", from
Absorbing the Desulfators Spikes, Thus stopping these spikes to Desulfate the Battery.

** This Desulfator Circuit can deliver pulses of 6 amps to the battery,
but it ONLY Draws about 100 mA, Average Current. (0.1 Amps)
So When charging While Desulfating, the actual charge current can be quite low Also.



If you have Two Batteries of the same A/H Rating and Size and both Fully Charged,
you can set the Sensitivity control to give a specific reading.
(Possibly a 100 uA reading on the first battery.)

Than Without changing the sensitivity Control, connect this unit to the second battery
and get a Comparative Test Reading.
The Battery with the LOWER Reading, Will be the Better Battery.



NOTE: The Range of Adjustment for this Sensitivity Control was "Arbitrary"
determined by me.

** Since I Didn't have a "NEW, EXCELLENT QUALITY, BIG Car Battery", this Range of Gain,
was just a Guess on my part, "Based on tests, using Batteries I presently have".
And so far it seem to be a Good Adjustment Range.

However, IF in the future, I find More Gain is Required to Properly test LARGE Batteries,
The 100K Pot can be Increased to a 250K pot, to get considerably Greater sensitivity.

Doing further testing, I find that the 100K pot is Basically Satisfactory.
It won't show a reading on a GOOD 12 Volt Car Battery, But it Will show a
reading on Batteries that do have a problem.

If you want the Greater Sensitivity, Just Increase this pot to 250K.

NOTE: On this Prototype, I just used a Trimpot control. However, you can put this board into
a suitable box and use a Convential Potentiometer For Better Ease of Adjustment.




Go Back to My "Projects Page"


Schematic UNDER CONSTRUCTION"
This is a Revised Schematic & Parts List.



This Article is "Subject to Modifications"

All Imformation in this Article is "Copyright protected".

 Chemelec 
 *Copyright © 2009*