Lead acid battery desulfator..

SgtWookie

Joined Jul 17, 2007
22,230
Well, using an ultrasonic transducer - I'm not aware of any that go up into the RF spectrum - not saying they don't exist, but by the same token they probably wouldn't be cheap. 3.26MHz is pretty low for RF, but mighty high for ultrasonic.

Besides, you'd have a time trying to get audio distributed around between plates that were choked with sulfate crystals. If the plates themselves were delivering the energy, it would surround all of the crystals at once.
 

retched

Joined Dec 5, 2009
5,207
Besides, you'd have a time trying to get audio distributed around between plates that were choked with sulfate crystals. If the plates themselves were delivering the energy, it would surround all of the crystals at once.
Good point.

Well, using an ultrasonic transducer - I'm not aware of any that go up into the RF spectrum - not saying they don't exist, but by the same token they probably wouldn't be cheap. 3.26MHz is pretty low for RF, but mighty high for ultrasonic.
And here you are correct again.

If we could find a frequency pulse that would result in the plates producing the wanted frequency...

..Using the plates themselves as the transducer. But then again, tuning would be a real problem. There would be no way to know how sulfated each plate was. And lead, being as dense as it is, would require huge spikes to produce such a high frequency. Who knows if the battery could even withstand the pressures. It surely would be easier OUTSIDE of the battery.
 

retched

Joined Dec 5, 2009
5,207
Hrmmm.. Now youve got me thinking. We are about to change over the batteries in our golf carts this week. I am going to grab eight or ten of the oldest ones and see what I can come up with.. I think I may even try the alum mixture. They should all have about the same usage, same age, and same manufacture.

Ill see about picking up four transducers.. trying one in each cell of these 8v batteries.

Ill get life and limb insurance first :)

What in the world do you need a 20MHz transducer for?

[ed]
I just filled out a request for quote and information form for a .5" x 3" 4MHz transducer that is acid safe
[/ed]
 
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SgtWookie

Joined Jul 17, 2007
22,230
4MHz? I thought our OP originally mentioned 3.26MHz?

They later changed their mind to a range of 3MHz to 4MHz (if I remember correctly) - but 4MHz is at the top end of the range.

Maybe it would be better to try for the low to middle of the range?
 

retched

Joined Dec 5, 2009
5,207
The transducer is apparently adjustable. I wanted the 4MHz for the high end so I would be able to do low to high sweeps. If the less expensive transducers are single "note" tuned, I will have to reconsider. I would also like to see what the OP has to say before I sweep this from under him.

If the 3MHz transducer is a large sum cheaper than the 4, Ill go for that.. Im just shopping for a datasheet and a quote.

Take a look here:
http://www.piezotechnologies.com/immersion.htm

They have pretty small 1MHz to 3.5MHz transducers for highly acidic and immersion purposes.
 

SgtWookie

Joined Jul 17, 2007
22,230
Well, everything they sell is custom-built to customer specifications; they don't have any "off the shelf" designs. Better have rather complete specifications before actually ordering anything.

I have a feeling you'll be getting a quote that will cause your jaw to drop.
 

Thread Starter

roltex_rohit123

Joined Jan 1, 2010
72
Hrmmm.. Now youve got me thinking. We are about to change over the batteries in our golf carts this week. I am going to grab eight or ten of the oldest ones and see what I can come up with.. I think I may even try the alum mixture. They should all have about the same usage, same age, and same manufacture.

Ill see about picking up four transducers.. trying one in each cell of these 8v batteries.

Ill get life and limb insurance first :)

What in the world do you need a 20MHz transducer for?

[ed]
I just filled out a request for quote and information form for a .5" x 3" 4MHz transducer that is acid safe
[/ed]
dont use any chemicals like chelators (EDTA) or any replacing substituents. if you are indeed interested in building up this circuit then i will provide you with all the nonelectronic help you need. i have a good knowledge of chemistry and spectroscopy. i could give you data all you need. i will also check the circuits if u have any idea in mind and help to find flaws and complete this desulfator successfully.
 

Thread Starter

roltex_rohit123

Joined Jan 1, 2010
72
The transducer is apparently adjustable. I wanted the 4MHz for the high end so I would be able to do low to high sweeps. If the less expensive transducers are single "note" tuned, I will have to reconsider. I would also like to see what the OP has to say before I sweep this from under him.

If the 3MHz transducer is a large sum cheaper than the 4, Ill go for that.. Im just shopping for a datasheet and a quote.

Take a look here:
http://www.piezotechnologies.com/immersion.htm

They have pretty small 1MHz to 3.5MHz transducers for highly acidic and immersion purposes.
3 MHz will have no effect and so would the 4 MHz. the frequencoes are exact and not even ± will do.
 

SgtWookie

Joined Jul 17, 2007
22,230
Ok, so what IS the exact frequency, or range of frequencies, that you require?

[eta]

In the 12th post on this thread, you wrote:
the frequency is 3.26MHz
Perhaps you found that on this page:
http://www.magnalabs.com/sulfation1.htm
from this little jewel:
(snip) By creating a wave form with the required 3.26 MHz frequency, coupled with a very fast rise time and a high amplitude pulse, more energy is developed to breakdown sulphation than by any other method believed to exist. This unique approach is now U.S. Patent Pending.
**Tuned to the molecular frequency of the sulphur crystal of 3.26 MHz.
I wonder if you happened to notice this snippet at the bottom:
Excessive Sulfation Didn't Occur Overnight, and Can't Be Removed Overnight

NOTE: The typical de-sulfation process can take upwards of several weeks (or longer) for larger batteries, when doing several batteries at once, and for those with severe sulfation. This is why many users purchase more than one unit so as to effectively effectively treat/condition more than one battery at any given time. Repetitive de-sulfation conditioning is recommended every few months depending on battery temperature and periods of in-activity etc.
In other words, I'm left suitably unimpressed. I don't see where it would be any faster than any other desulphator that's around.
 
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retched

Joined Dec 5, 2009
5,207
Ok.. Sarge is letting the air out of my tires..

I am glad you are doing so before my bank statment does after this experiment.

@roltex_rohit123:

I was under the assumption this was something you wanted to build and you were asking for help.? Are you trying to repeat an already published result or are you attempting to "think outside the box" and try for improvements?

@SgtWookie

I suspect the transducers will be a rather pricey purchase. If the design was somthing I could convince myself to believe in, it would be worth the price (im talking under a grand).

I was thinking about the lead plates.. What frequency would have to be "played" through the lead to make the lead resonate at 3.26MHz?

If it were possibile to use two opposing plates as a "noise canceling" setup, where the left plate rang at 7MHz and the right rang at 3.74MHz, the resulting impacts would result in the 3.26MHz and quite a few harmonics.

I am starting to dive in too quickly here..

I am also wondering if the electrolyte were more acidic, if the process would be strengthened or hindered. There would be more sulfur in the mix that may keep the sulfate crystals from re-absorbing as efficiently. Could salt-water produce a positive effect to deal with the sulfation?
 

SgtWookie

Joined Jul 17, 2007
22,230
Well, you have a half-dozen batteries or so to fiddle around with.

Something that I did when I was 16 or 17 was to take a battery, and dump all of the acid out; drained it well.

Then I rinsed it out with water from the hose best as I could.

Then I mixed up a half-box of baking soda (!) in warm water; a gallon or so in a big bucket.

I filled up the battery with the water/baking soda mix, and agitated it some for maybe an hour. Dumped that out, rinsed it out, and filled it up again with baking soda/water mix, and let it sit for another hour or so. There was lots of bubbling and fizzing.

Then I dumped that out, and filled/dumped the battery a few more times with just plain clean water. I left the thing to drain overnight. The plates turned kind of pink; I don't know why.

Filled the battery back up with acid, and charged it. It worked for at least a few months; I can't even remember which vehicle it was in now. Don't know if it would work with batteries they make nowadays. That was in the early 70's, and batteries had lead plates. Nowadays, they have a thin framework of lead with lead paste applied. I think the positive plates have a good bit of calcium in them (maybe it's the negative plates; it's late, I'm tired, and don't feel like looking it up)

None of what I did at that time was scientific; I didn't even use a specific gravity tester to check the cells. But, I'm pretty sure it got most (if not all) of the sulfate crystals off the plates.
 

retched

Joined Dec 5, 2009
5,207
Yeah, but thats no fun. Baking soda only costs $1. Jeesh. :rolleyes:

I have 6 batteries, deep cycle. The plates are about .25" and 'appear' to be solid lead. I have one that ruptured that I am further dissecting.

I wish I had the where-with-all when I was that young to get started in electronics.

Anywhoo, The six I have chosen have been in service daily for about 13 months. An 8 hour day (About 3 hours of usage), and put on charge nightly.

I am considering washing 3 (with about the method you described) and using 3 different recovery methods with the remaining.

Alum (pickle battery)
standard desulfinator (webstore bought)
standard desulfinator on a vibra-table

I want to see if agitation will have any effect during desulfination process.

Some of these batteries (not the 6 I have chosen) have shorted cells, apparently from sulfation, so I am guessing the charge/discharge rates that is par for these batteries lend well to sulfation.

I will follow specific gravity weekly.
 

SgtWookie

Joined Jul 17, 2007
22,230
I wouldn't use a vibration table. You will likely cause the plates to separate from the buses due to metal fatigue. Slow agitation with no "bumps" would probably be OK.

Have you started taking the ruptured battery apart? Better be careful, some of the cells may still have a charge. If you ran a metal blade through them, you could cause some very high currents that would get the blade very hot at least.

You might start by cutting off the bottom of the battery. The bottom is usually just empty space when new (maybe an inch or so high), but begins collecting sediment as the plates disintegrate. If the bottom gets filled up, the plates will short out.
 

retched

Joined Dec 5, 2009
5,207
The ruptured battery has been run-over by another golf cart. I appreciate the warning. There is nothing but pieces-parts left.

Ok, the vibration table is out. If I had a more 'gentle' way of constant agitation, i may consider it. Also, the more research I do, the more I think I want try two different charge pulses, rather than the agitation.
 

SgtWookie

Joined Jul 17, 2007
22,230
Try a low-speed gear reduction motor with an eccentric (cam) on the shaft.
Use a board (like a small chunk of plywood) that's hinged on one side. Use some flanges matched to the size of the battery base to keep the battery from sliding around. Just a nice slow agitation without any bumps.

Here's a rough idea of what I'm talking about. Note that the battery caps are in line with the hinge pivot points so that agitation is side to side instead of end to end.

 

Attachments

retched

Joined Dec 5, 2009
5,207
...ok. Im going to weigh a battery to find a geared motor that will handle at least that weight. Good idea.

I have had the agitation idea in the back of my mind for months now, so it would have been a little bit of a disappointment to drop it.
 

SgtWookie

Joined Jul 17, 2007
22,230
Keep in mind that what I posted is a very rough concept.

You could move the "rocking board" pivot point under the battery, if you could keep the eccentric captured so that it wouldn't tip over. You don't want any "banging against the stops" going on, and you wouldn't want the agitation to be more than a slow rocking motion. Don't forget you have slag in the bottom of the battery that could short out the plates if you stir it up too much.
 

retched

Joined Dec 5, 2009
5,207
Ahh.. I didnt even think the motion could cause the sediment to create a short. hrmm.

That could definitely cause a heating problem.

I built a little rocker board today. I connected a piece of pvc to a .75" plywood circle about 1' dia. The 1.5" pvc has a 2" pvc sleeve on it to allow a smoother movement. I can adjust the cam along the radius to change the rocking motion. As well as changing the distance from the hinge gives a pretty good range of motion. Using plywood rather than stock board, the flexibility also adds a gentleness to the motion. Like a spring board.

I may just pulse this one rather than add the charger to it as well.

Any idea at what temperature the sulfation crystals melt/dissolve in the bath?

I was thinking if the sulfates were dissolved in the mixture, the re-combination would be more effective.
 

Thread Starter

roltex_rohit123

Joined Jan 1, 2010
72
Ok, so what IS the exact frequency, or range of frequencies, that you require?

[eta]

In the 12th post on this thread, you wrote:


Perhaps you found that on this page:
http://www.magnalabs.com/sulfation1.htm
from this little jewel:


I wonder if you happened to notice this snippet at the bottom:


In other words, I'm left suitably unimpressed. I don't see where it would be any faster than any other desulphator that's around.
the desulfator at lower frequency is like a carbine gun killing nepolean's army while at 3.26 its like a atom bomb. what will u prefer?
 
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