Lead acid battery desulfination?

I believe that the approved technique is to take it to an auto parts store and exchange it for a new one.

And yes -- it's a smart-ass answer. But then, I suspect that if desulphination really worked, then every battery shop and car dealership would have a machine.

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com

On a sunny day (Sun, 27 Jul 2014 13:50:09 -0500) it happened Tim Wescott wrote in :

Some do.

I've read US army (whatever you may think of it) has nice desulphators in use, google says,

It is good business to sell people a new battery. But already now I can tell you desulphation is possible, just looking for a faster way. I was very sceptical myself until I did see capacity go up again. It is still running... on pulse now.

Desulfation-

pt=Battery_Chargers&hash=item27e82d422f

Let us know how it works out. I suspect that you'll just end up with a battery that's never quite 100% capacity, and that either wears out quick or isn't reliable.

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com

--
Teach a corpse how to work and you can get it to pay for its own 
funeral. ;) 

John Fields

Well, you could try the epsom's salt rejunevation technique, a search will turn up lots and lots of hits. May not work, but it is quick :-). Never tried it myself so curious if you do it how it goes.

Been trying to 'desulfinate' a 13Ah lead acid battery now for a few weeks. The method I used is to run 200 mA at 16V into a 12V battery. The battery had only 1/10 of capacity, now it has 1/8. Takes too long for my liking, would several month that way.

So did some googling, and found this circuit diagram only:

Basically a flyback where the flyback impulse goes into the battery. You can buy that sort of stuff on ebay too (30$ ex shipping):

But I thought why bother, I have such a flyback powering some HV (for a helium neon laser). So I took a diode from the collector and put that back into my battery. Been running now a few hours, about few hundred mA average... nice pulse, 15 kHz repetition, will leave it on some time

Anybody any experience bringing old sulfated lead acid batteries back alive? Circuits?

I've tried a couple of charger tricks:

- A PWM regulator that maximizes ripple current

- Momentarily draw a huge current

Periodically drawing a huge current seems to work. It fixes the case where a battery stops drawing current and won't charge. I don't know if that's sulfate buildup or just welding some conductive paths in the sponge lead.

In the end I came to the conclusion that there's no good way to use lead acid batteries. They're heavy, short-lived, and unreliable. The sponge lead falls off. The lead grids crack. Sulfate buildup kills them. The rivets between cells corrode. They randomly go high impedance for a while.

Nickel Metal Hydride performs better in all manners except that they're difficult to charge. I use only lithium batteries now. There are some different options for power density versus ruggedness there.

It all depends on the use. I wouldn't use NMH or Lion for a starter battery and would be hesitant for anything that's float charged for years at a time (LIon, maybe), like egress lighting. I really don't see the use for NMH anymore. LIon has pretty much taken over that space. LIon's biggest negative is its cost (and fire hazard if not properly cared for). NMH is dirt cheap and, for those who lose sleep about such things, "environmentally friendly". For car (starter) batteries, nothing comes close to lead-acid. Cheap, reliable, and effective.

Lightly sulfated battery's can show an improvement. heavily sulfated batteries don't recover. The best method is the high frequency fly back, the idea is to loosen the sulfur so that it can be reabsorbed into the electrolyte. As the sulfur builds on the plates it becomes hard and is difficult to remove with normal charging.

Cheers

The telephone system routinely rebuilt their batteries after aging and sulphination lowered the battery capacity. They re-smelted the lead and that sure got rid of the sulphate! It's not just new paint disease, the new battery really DOES solve the problem.

On a sunny day (Sun, 27 Jul 2014 13:52:22 -0700) it happened Kevin McMurtrie wrote in :

I have some LiFePO4 batteries on order from ebay. Those seem to have a very long life, and are safe. Nothing arrived, they asked me for feedback, then they send me a message they got the battery back from the shipping company. It could be airlines are paranoid about anything that has 'battery' in it... So they resend some weeks ago, still has not arrived... maybe same procedure, will ask again. I would really like to test those

More charge-discharge cycles, but VERY expensive.

On a sunny day (Sun, 27 Jul 2014 16:18:56 -0700 (PDT)) it happened whit3rd wrote in :

Melting lead is energy expensive.... :-)

On a sunny day (Sun, 27 Jul 2014 17:18:25 -0400) it happened Martin Riddle wrote in :

Thank you, will let it run some days and then see what happened to capacity.

I recovered a lead-acid battery that was so bad that the current it initially passed was only a few milliamps at 120VAC. The trick is (a) put a diode across the battery to protect it from reverse polarity, (2) use a capacitor in series with an AC source; use a variac to adjust line voltage for C/20 current. Beware of *EXPLOSIVE* hydrogen; keep area well ventilated. If you are in more of a hurry, use C/10 but no more.

The battery i recovered (using adjustable AC source, series capacitor and protection diode) seemed to recover to full capacity - including cranking power.

I strongly suggest tat you do NOT use epsom's salt or any other non-compatible crap. The battery is guaranteed to not last long if you try that.

• Sulfate buildup. Te worse it is, the more the voltage is needed to get a decent current. "Zapping" tends to knock off the sulfate in flakes which drops to the bottom, and battery life as well as reliability is decreased.

• Then toss the car away; i am sure you could find a taker or two...

• Not true; proper method of de-sulphation works on any sulfated lead-acid battery, and in many cases can lead to a battery fully recovered.

The best method is the high frequency fly

• Nope!

• Key word "normal".

On a sunny day (Sun, 27 Jul 2014 22:47:21 -0700) it happened Robert Baer wrote in :

Interesting, and easy to do.

On Mon, 28 Jul 2014 05:33:32 GMT, Jan Panteltje wrote as underneath :

I ran a commercial desulphator on a below par but still in use car (12V)

8 year old OEM (filled for life) battery for 2 months measuring the 100 Amp discharge voltage accurately at weekly intervals from prior to use to the end. The desulphator was doing a lot, car wouldnt start after 3 days without recharging! The battery was fully charged to peak prior to each measurement. Here is a pic of the desulphator output while working: The bursts are at about 63KHz. Conclusion: Its a snake oil solution, just doesnt work on this test with a premium battery that has never been mistreated and is just loosing peak cold cranking capacity, measurements showed 10.2v (after 10 seconds under 100A load) from start to finish. A brand new battery under the same test only shows about .5v more, its a fairly severe test. C+