I need to build a circuit that removes sulphate deposits from lead acid batteries by using a 555 timer generated pulse to cause high frequency resonnance in the battery (pdf attached - the cited web page doesn't seem to exist any more unfortunately). This seems to be a circuit that has been widely used and with notable success.



I got all the parts on a recent trip overseas, as I cannot get them where I live. Unfortunately the power MOSFET Q1 supplied was in a bag labelled "IRF9Z34" but was actually an IRFZ34 - this is an N-channel device instead of a P-channel device, but otherwise seems pretty similar.

Since I need the circuit rather urgently and it would take me about 2 months to get a replacement, I am wondering if I could use this device with a few small modifications to the circuit? My assumption would be that I could basically replace the IRF9Z34 with the IRFZ34 by inverting the connections to the power lines, but am unsure of the other adjustments to the circuit that would be necessary. Also would the voltage limits of C6 remain unchanged or not (and still go to positive rail or to negative), and likewise should the inductor/choke remain on the negative power line or be moved to the positive power line? I am assuming the necessary changes would be limited to the arrangement of Q1, L2, L3, D1 and C6.

Could some kind soul perhaps confirm that such a modification is possible and guide me through the necessary changes? It is the 24V circuit version I need as shown above (there is also a 12V version in the pdf).

Also regarding the inductor/choke: given the error in the supply of the MOSFET I am a little suspicious about the inductors I received, as they all look identical and all in unmarked reels covered with shrink-wrap, and all the same dimensions (1cm long diameter 0.8cm) - I got all three L1, L2, and L3. Could it be that they are all chokes or all inductors, and would it matter? What about the current rating? Just on the basis of the tiny amount of solder-covered wire visible at the terminal pins, it appears the thickest wire is the 1000uH 100mA L2 with (extremely approx) about 0.2 to 0.3mm, then the 220uH 6+A peak L1 with similar size or very marginally less, then the 330uH 6+A peak L3 with substantially thinner wire about 0.1mm. The L1 and L2 estimates are very unreliable, the L3 a bit better as the wire going to the spool is visible; however what is certain is that all three have very thin wires, and L1 and L3 seem suspect to me. Are these observations plausible for the specified components? I would expect much thicker wire for L1 and L3, and maybe larger components.

 

I need to build a circuit that removes sulphate deposits from lead acid batteries by using a 555 timer generated pulse to cause high frequency resonnance in the battery (pdf attached - the cited web page doesn't seem to exist any more unfortunately). This seems to be a circuit that has been widely used and with notable success.

View attachment 177118

I got all the parts on a recent trip overseas, as I cannot get them where I live. Unfortunately the power MOSFET Q1 supplied was in a bag labelled "IRF9Z34" but was actually an IRFZ34 - this is an N-channel device instead of a P-channel device, but otherwise seems pretty similar.

Since I need the circuit rather urgently and it would take me about 2 months to get a replacement, I am wondering if I could use this device with a few small modifications to the circuit? My assumption would be that I could basically replace the IRF9Z34 with the IRFZ34 by inverting the connections to the power lines, but am unsure of the other adjustments to the circuit that would be necessary. Also would the voltage limits of C6 remain unchanged or not (and still go to positive rail or to negative), and likewise should the inductor/choke remain on the negative power line or be moved to the positive power line? I am assuming the necessary changes would be limited to the arrangement of Q1, L2, L3, D1 and C6.

Could some kind soul perhaps confirm that such a modification is possible and guide me through the necessary changes? It is the 24V circuit version I need as shown above (there is also a 12V version in the pdf).

Also regarding the inductor/choke: given the error in the supply of the MOSFET I am a little suspicious about the inductors I received, as they all look identical and all in unmarked reels covered with shrink-wrap, and all the same dimensions (1cm long diameter 0.8cm) - I got all three L1, L2, and L3. Could it be that they are all chokes or all inductors, and would it matter? What about the current rating? Just on the basis of the tiny amount of solder-covered wire visible at the terminal pins, it appears the thickest wire is the 1000uH 100mA L2 with (extremely approx) about 0.2 to 0.3mm, then the 220uH 6+A peak L1 with similar size or very marginally less, then the 330uH 6+A peak L3 with substantially thinner wire about 0.1mm. The L1 and L2 estimates are very unreliable, the L3 a bit better as the wire going to the spool is visible; however what is certain is that all three have very thin wires, and L1 and L3 seem suspect to me. Are these observations plausible for the specified components? I would expect much thicker wire for L1 and L3, and maybe larger components.


View attachment 177119

Here is one with NFET. See what you might be missing and we can see what we can do.

https://320volt.com/en/battery-desulfator-circuit/

 

Thanks for your suggestion ronv, but I need to stick to the current circuit - not least because I have (almost) all the components and cannot buy components where I live, I just want to switch the MOSFET.

 

Which mosfets can you get hold of??

Failing that just invert the signal from Pin3 with an Npn.
Same circuit diagram here...
http://www3.telus.net/sail/sj23/e_electrical_tips/e04a.html



The Frequency is approx 1.3Khz,



Moderators note : reduced image size

 

Here is a putative circuit replacing the P-channel MOSFET IRF9Z34 (Q1) by the N-channel MOSFET IRFZ34 (Q2).

All I have done is I've switched the circuit around according to my ignorant assumptions, using the N-channel circuit linked by ronv as a little bit of a guide.

I DON't KNOW WHAT I AM DOING!!! So I hope some kind soul who does will check whether what I have done is correct or not.



The only thing I have changed is the right hand side: Q1/2, L2, L3, D1 and C6.

Would the polarity of the generated pulses change with this circuit???

 

The problem is the pulse durations on/off timings are inverted due to the Nfet, this effects the design, you can use an N fet with a npn inverter driver transistor to revert to the same output.

 

Would the polarity of the generated pulses change with this circuit???

If you want to PM me your address, I think I have some PFETS I could mail to you.
Post a picture of your inductors and we can see if they are okay. Maybe.

 

Here is a picture of the inductors, 1000uH on the top, 330uH on the bottom

If you want to PM me your address, I think I have some PFETS I could mail to you.

Strange - I cannot see how to send a PM! It might be related to my browser options/age, though I tried from my mobile as well. What do I need to click on?

 

Hello,

The given schematic is for 24 Volts.
As the voltage regulator is in the - lead. The 555 is lifted, so the pulses will be between 12 and 24 Volts.
The N-fet will be on always.
Do you intend to use the 24 Volts circuit with a N-fet?

Bertus

 

Do you intend to use the 24 Volts circuit with a N-fet?

Thanks for pointing that out. Yes, the idea of "Putative circuit Version 1" is to use the circuit with an N-fet. The idea is to make use of the components I have since it would take a long time to get replacements.

With the original circuit at the top the pulses from 555 will also be between 12 and 24 Volts, shouldn't that mean the Q1 P-fet will always be off? Why is that not the case - is it something to do with the inductors pulling the drain down, and could the inductors in my putative circuit be rearranged so that Q2 will switch on and off?

As you can see, my understanding of the circuit is rather limited, sorry about that.

 

Hello,

With a P-fet and the 555 is giving 24 volts, the P-fet is off.
With a P-fet and the 555 is giving 12 volts, the P-fet is on.

The gate voltage of the P-fet is relative from the positive power line.

Bertus

 

Here is a picture of the inductors, 1000uH on the top, 330uH on the bottom

View attachment 177386



Strange - I cannot see how to send a PM! It might be related to my browser options/age, though I tried from my mobile as well. What do I need to click on?

Boy.
Your not having much luck.
Here are some similar inductors with a maximum current between 0.56 and 1.35 amps for the 330 Uh and 0.75 amps max for the 1000 Uh.


When I simulate it the 330 needs about 2.4 amps while the 1000 needs around .7 amps.


You might get away with it. Or it might smoke.
I use the blue screen so the inbox is in the top right hand corner.
I built about a dozen of these for my golf buddies a few years ago. I can't say they worked.
I have had some luck charging a 12 volt battery with about 15 or 16 volts while limiting the current to an amp or 2.
I do this until the specific gravity gets back in the green.

 

My understanding is that the pulses are bigger, the more the sulphate deposits on the battery, and that they could be "up to 6 Amps" (which is also likely where they will start off in my case). The parts list specifies "6+ A peak" for the 330uH and 100mA for the 1000uH. My photo was from the side and doesn't show the dimensions of the wire - it is pretty thin!! (I don't currently have a camera that could take a good enough picture for the wire). I can well imagine that the 1000uH one might be OK at 100mA but the 330uH would I fear blow on the very first 6A pulse. But on the other hand I have little experience with inductors so I really don't have any feeling for the amount of current a thin conductor can take on an inductor. Then there is the frequency coming into the equation, unlike a simple resistive load. Should I cut off the shrink-wrap of the 330uH and take another photo?

I can reach the inbox OK, but there is no link to starting an email. I suspect it is a browser problem (Grrrrr, why should a website be allowed to force me to change my software?). On the same menu hovering the mouse over "Alerts" causes the right-most edge of a window to appear on the left-hand side of my screen - what the content of the window says I have no idea since I can only see the end of each line!

My batteries are on an inverter, which (mis)manages all the charging - I suspect it is acting in a way optimal for the formation of the sulphate deposits.

I've been toying with trying to separate the charging off from the inverter using diodes (i.e. so that the inverter can draw current out of the battery, but not push current back in), but (a) I don't at present have a sufficiently high-powered 24V charger to replace the charging function of the inverter, and (b) I wonder what the inverter will do when it is connected to the batteries through diodes - maybe there will be unforeseen effects ...

The table from Mouser quotes resistances in mOhms for some of the inductors, that is not the DC wire resistance, surely? (Both of mine give essentially zero on the lowest 200 ohm scale of my multimeter)

(I don't currently have a camera that could take a good enough picture for the wire)

I managed to get an adequate photo:



Yes, that hair-like filament is the wire it is would with, as far as I can see (that is the 330uH)

 

Are your AAC pages orange or blue? This site has two schemes. The orange is the default. In my experience, the orange scheme is not as forgiving as the blue scheme. I use the blue scheme. Fortunately, the site allows you to pick which one to use. Perhaps using the other scheme will let you do what you need to do.

So which do you use?

Knowing that, we may be able to help you change your settings and see if that helps. BTW, what OS and browser (including version) are you using!

 

I managed to get an adequate photo:

View attachment 177462

Yes, that hair-like filament is the wire it is would with, as far as I can see (that is the 330uH)

The resistance is in milliohms. So pretty low.
I think you need over 10 posts before you can PM. So you may be okay now.

 

Well, according to the display above I had 9 posts (prior to this one) and am still unable to PM, so maybe it will be possible after this one. I was using the red scheme, have just changed to the blue (looks better!)

 

Do I need at least 10 posts to PM, or more than 10? Maybe I'll be able to tell after this one!

Edit: I now have 11 posts, and still cannot PM. There is no "start a new conversation" link, or link to send a conversation to someone, or anything like that. Maybe the PM needs to be enabled manually by a moderator?

 

hi Bhante,
MOD:
Admin have checked the PM feature, no problems found, so please retry.
E

 

Do I need at least 10 posts to PM, or more than 10? Maybe I'll be able to tell after this one!

Edit: I now have 11 posts, and still cannot PM. There is no "start a new conversation" link, or link to send a conversation to someone, or anything like that. Maybe the PM needs to be enabled manually by a moderator?

Nope... where are you looking for the button? Basically, it works like this.

1. In the thread, click on the person’s name to whom you wish to PM.
2. On the pop up which is displayed, there is a selection to “Start a Conversation”.
3. Click on that...

 

Yes I was looking for something like "Start a new conversation" but didn't exist. Anyway, PMs have been enabled now within the last 3 hours, problem resolved. Maybe some other MOD already enabled it before Eric Gibbs looked at it. Thanks to all those concerned who helped resolve the problem, including others who chipped in!