simple desulfator circuit - question

[lynx]

Your Frequency Measurements do NOT Appear Correct.
The Duty Cycle on this circuit Might be too Short for your Freq-Counter.

It Appears Those Values are NOT CORRECT.
Most Resistors ar +/-5%
I Suspect your measuring them IN-CIRCUIT?
YOU CAN'T MEASURE THEM CORRECTLY, WHILE IN-CIRCUIT.
Remove ONE END to Test Them.

In Fact:
With 470K, 22K & 2.1nF, Frequency at the 555, Pin 3 Will be 1,336 Hz.
If 390K, 19.8K & 2.1nF, The Frequency will be 1,600 Hz.
The Low Side Duty Cycle on these is only about 4.5%

Can you Post the Waveform you have at the Battery?

here's the waveform from the battery, checking again at pin #3 it's 1.8KHz

 

[chemelec]

Your Scope trace doesn't show the actual voltage rise on the waveform.
But that voltage is Probably To Small of a voltage to accurately measure the Frequency.

And your Frequency is Not correct for either of the part values.
I know my calculator is correct.

 

[lynx]

Your Scope trace doesn't show the actual voltage rise on the waveform.
But that voltage is Probably To Small of a voltage to accurately measure the Frequency.

And your Frequency is Not correct for either of the part values.
I know my calculator is correct.

how come the scope doesn't show it? i know it doesn't have much of sensitivity (it's only 100mV) but for what i'm trying
to measure it should be fine...

to sumarize does the newly built desulfator on the pcb works the way it should? how could i know?...don't tell me "wait and and see!"

 

[4pyros]

here's the waveform from the battery, checking again at pin #3 it's 1.8KHz
View attachment 84757

Look at the waveform on pin 3 and post a pic here.

 

[lynx]

Look at the waveform on pin 3 and post a pic here.

that's the waveform i got from pin #3 i didn't connected anything wrong...small
posibility i was careless because i was holding the camera, but i don't think so, the frequency seems to change with the voltage?
i don't know...at the time of the measurement the battery has been charged for awhile... i haven't changed
any components.

 

[chemelec]

YES, A Very Narrow Pulse going Downward.
That Waveform Looks Correct.

The Size of the Waveworm at your battery is Small, Because the Internal Resistance of the Battery, Tries to Short it Out.
The Better the Battery, The Smaller it will be.

On "My Battery Desulfator", I also have a Tester that Shows any Improvement in the desulfation Process:
http://chemelec.com/Projects/Bat-Desulfator/2012-Desulfator.htm

 

[lynx]

YES, A Very Narrow Pulse going Downward.
That Waveform Looks Correct.

The Size of the Waveworm at your battery is Small, Because the Internal Resistance of the Battery, Tries to Short it Out.
The Better the Battery, The Smaller it will be.

meaning i'm on the right way? doesn't it needs any trimming? i mean this device it is suppose to work with some kind
of resonant frequency of the battery.. i guess it's similar thing as the dentist removes tartar from the teeth, so other than
i see it doing noise...what else i could check so i can be sure it functions correctly? thanks for supporting me on all this
also the rest of the people here.

 

[chemelec]

This device Does NOT work on the Resonant Frequency of the battery.
If a Battery Does have a Resonant Frequency, it would be different for Every battery, and it would be Definately Below 1 Hz.

All this circuit does is to put a Somewhat High Current Pulse into the battery, In the Hope that it will break-up any Sulfation.

Lynx Wrote, what else i could check so i can be sure it functions correctly?

You could Build the Tester Portion of My Desulfator, to see any Progress in the sulfation process.

 

[NorthGuy]

The voltage at pin3 is ok. The signal at the battery (I assume this is current, not voltage) is ok too, and they both seem to be the same frequency.

Is there any way you can put scale on the graph, say what is the peak current at the battery?

 

[chemelec]

I Wound up the Proper Coils and Proto-typed the circuit up.

The Actual Measured Frequency at Pin 3 is 1322 Hz.
According to the SCOPE TRACE, It is also the Same Frequency at the Battery.
But I Can Not Measure it Correctly on my Frequency Counter.

The Scope trace 1 is with a Badly Sulfated Battery.
Voltage Division is set at 1 Volt per Division, so my Guess the Voltage is about 0.3 Volts.

The Scope trace 2 is with a Less Badly Sulfated Battery.
Voltage Division is set at 1 Volt per Division, so my Guess the Voltage is about 0.1 Volts.

My OPINION, Neither of these pulses will do much in Desulfating a Battery

 

[MrAl]

Hi,

When i tried to 'desulfate' my battery i used a spike of current from a wall wart and high value capacitance. I didnt get very good results but it is hard to figure out why.
From what i could tell maybe the capacity went up a little but not enough to make it worth doing.

 

[NorthGuy]

The Scope trace 2 is with a Less Badly Sulfated Battery.

Is this voltage? It looks strange because short current pulses are supposed to decrease battery voltage (because power is drawn from the battery) and then it would recover back while the FET is off.

 

[lynx]

You could Build the Tester Portion of My Desulfator, to see any Progress in the sulfation process.

your replies were very helpful if i knew about your project earlier, i would have built yours...
btw the large inductor i'm using on the pcb it's 174uH do you think it's mandatory i should use 220uH
still i don't totally understand the way the circuit works...i guess less inductance then less powerful pulse
is sent to the battery...but what's the role of the second coil?

[EDIT]

The Scope trace 1 is with a Badly Sulfated Battery.
Voltage Division is set at 1 Volt per Division, so my Guess the Voltage is about 0.3 Volts.

The Scope trace 2 is with a Less Badly Sulfated Battery.
Voltage Division is set at 1 Volt per Division, so my Guess the Voltage is about 0.1 Volts.

My OPINION, Neither of these pulses will do much in Desulfating a Battery

wait...what do you mean neither of these pulses will do much in desulfating?
as you said earlier it is suppose a good battery absorbs the pulse so the voltage
is less right?!

 

[chemelec]

MrAl, I Don't know How you can get a SPIKE, from a Wall Wart and a Capacitor.

Also fully Desulfating a Battery Usually takes Week to accomplish.

Using the Circuit posted on here, It is Self Powered by the battery, so it also Discharges the Battery.
This can happen Quite Quickly on an Already Bad Battery.
So as well as Desulfating it, It also needs a "Constant Trickle Charge".

Additionally on the Schematic it shows a 2 Amp Fuse.
This FUSE is IMPORTANT, because if the Mosfet Shorts out, It can Creratea FIRE or cause the Battery to Explode.

 

[chemelec]

Is this voltage? It looks strange because short current pulses are supposed to decrease battery voltage (because power is drawn from the battery) and then it would recover back while the FET is off.

These Oscilloscope Picture are the Voltage Spikes created by the Circuit.
These SPIKES are POSITIVE, OVER the Battery Voltage. (NOT NEGATIVE)
So assuming battery is 12.6 volts and a 0.3 Volt Spike, Total voltage would be 12.9 Volts as the Spikes Occur.

Yes the Battery Somewhat Recovers between Pulses, But Reguardless, The Battery Loses Power.

The Better the Battery, the Lower its INTERNAL RESISTANCE, So the LESS NOTICABLE the Spike.
On a PERFECT Battery (Which Doesn't really Exist) The Spikes would be ZERO VOLTS.

 

[NorthGuy]

These SPIKES are POSITIVE, OVER the Battery Voltage. (NOT NEGATIVE)

Of course. Sorry, I wasn't thinking

The Better the Battery, the Lower its INTERNAL RESISTANCE, So the LESS NOTICABLE the Spike.
On a PERFECT Battery (Which Doesn't really Exist) The Spikes would be ZERO VOLTS.

It depends a lot on the state of charge. When battery is discharged, it can take current without voltage rising. When it is full, the voltage will rise more.

Also, the "internal resistance" will be lower for bigger batteries because they, obviously, can take more current.

 

[chemelec]

your replies were very helpful if i knew about your project earlier, i would have built yours...
btw the large inductor i'm using on the pcb it's 174uH do you think it's mandatory i should use 220uH
still i don't totally understand the way the circuit works...i guess less inductance then less powerful pulse
is sent to the battery...but what's the role of the second coil?

[EDIT]

wait...what do you mean neither of these pulses will do much in desulfating?
as you said earlier it is suppose a good battery absorbs the pulse so the voltage
is less right?!

Sorry I, Missed this post Earlier.

Personally I Don't consider My Desulfator as being really good Either.
(Or any Other Desulfators I have ever seen.)
But it has the Advantage of the Monitoring Circuit to see if the battery Improves in quality.
In Most Cases, it is better to Just BUY a New Battery.

The Two Coils, Diode and Capacitor Create a Positive Voltage BOOST of the signal.
(Just putting in a Single Coil, you get a Negative Spike.)

The Exact Inductance Values are Not that Critical, But that 100 mA Choke has too Low of a Current Rating.
It Probably is Saturating.
These Coils should also be Low DC Resistance and High "Q" Types.

 

[4pyros]

the frequency seems to change with the voltage?

That is a function of the 555 timer.

what else i could check so i can be sure it functions correctly?

Maybe try a dummy load while powering the circuit from a power supply?

 

[lynx]

The Exact Inductance Values are Not that Critical, But that 100 mA Choke has too Low of a Current Rating.
It Probably is Saturating.
These Coils should also be Low DC Resistance an d High "Q" Types.

hi, "probably" is not enough for me.. either it does or it doesn't

the design i think it is from a magazine...found the pdf from a forum, but i guess its not allowed to upload it here so i gave a link of the schematic i found on google...

by the way check this out..this guy sells them on ebay look how small both inductors are..


**broken link removed**

also you said that depending the battery state the pulse would be different...

'So assuming battery is 12.6 volts and a 0.3 Volt Spike, Total voltage would be 12.9 Volts as the Spikes Occur.'

this is not what i was expecting,

the author of the article states the following:

"The peak voltage drop across the batterycan initially be as high as 50 volts. With continued
treatment, this peak voltage will decrease as the battery’s internal resistance gradually declines."

somewhat it is what you said...but here we're talking about few mV and not about volts, which
i guess they are needed to shock and "wake up" a battery.



NorthGuy at the battery i was measuring voltage...

4pyros so i guess as the voltage falls the frewuebcy will raise?

 

[4pyros]

so i guess as the voltage falls the frewuebcy will raise?

It is possible; here is a post on it;
https://www.electro-tech-online.com/threads/555-timer-frequency-change-problem.105445/