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From: John De Armond
Subject: Re: Does the battery desulfators work?
Message-ID: <>
Date: Thu, 20 Feb 2003 18:19:56 -0500

On Tue, 18 Feb 2003 23:12:47 GMT, "Norman Winters" <> wrote:

>Hi, there,
>Has anyone here run tests on those widely touted
>de-sulfating pulse packs on *industrial* lead-acid batteries?
>(the type which emit a very low-level but high-frequency current)
>they are advertised as "returning lost life due to battery sulfation"
>I've always said that if a battery is properly changed and
>maintained that  a pulse pack (even if it could breakdown sulfation) is
>as the battery would not be sulfated in the first place

Then you always said wrong.

>I'd appreciate any comments from anyone else who has run a similar

Yes, I've extensively tested both the design presented there and a commercial
model (battery tender) in my lab.   Both work as advertised, with this
homemade design working better.  I wrote a paper on the results of my research
but given the current quality and ambience of RORT I decided to just keep my
information to myself.

From memory, a few bits of data.  The Battery Tender took a shot Group 27 deep
discharge battery from a measured 18 ah capacity to 86 ah after about 6 weeks
of application.  The capacity was measured using a computerized data
acquisition system with the discharge rate controlled to C/20.

Testing this homemade design on a completely shot (would not accept any
charge) Group 24 deep discharge batter, 2 weeks of operation brought the
capacity up to about 35 ah.  This restoration did not last long after the
pulser was removed but as long as the pulser operated, the capacity remained
at that level.

In both cases I operated the pulser until it showed no further improvement in

Since the unit is very inexpensive and works as advertised, I see no reason
not to install one on a new battery and let it do its thing from the very
beginning.  The only downside I can think of is the pulsing might generate
enough EMI to interfere with TV or AM radio.  I've personally seen no evidence
of that.


From: John De Armond
Subject: Re: Does the battery desulfators work?
Message-ID: <>
Date: Sat, 22 Feb 2003 04:09:46 -0500

On Thu, 20 Feb 2003 23:24:00 GMT, "Bob Peterson" <> wrote:

>In any case, was the battery able to be returned to normal service?  Or was
>it something that was so temporary that it was of little long term value?

In this particular case, the batteries were removed from service in my MH.  I
put them back in service on my computer room UPS.  They're still there and
working.  I recently had a power outage that lasted most of the day.  The
batteries kept the systems up during that time.  By my calculation this
required about 50 ah which indicates that the batteries are still in pretty
good shape.

In other testing I'm seeing evidence that the battery will fairly rapidly
revert to sulfation if the pulser is disconnected.  But it appears that the
fix is "permanent" as long as the pulser is left on the battery.  No big deal
because the pulser has no effect on normal operation.

I don't have enough evidence yet to state the above as fact but the
indications are strong.


From: John De Armond
Subject: Re: Does the battery desulfators work?
Message-ID: <>
Date: Sat, 22 Feb 2003 16:33:17 -0500

On Sat, 22 Feb 2003 17:42:07 GMT, "Bob Peterson" <> wrote:

>One would be inclined to believe that battery chargers would be made with
>the pulse technology built in.  Modern electronics makes this kind of thing
>dirt cheap.  I wonder why its not?

Possible reasons:

a) they are.  You just don't (yet, perhaps) find 'em at Wal-mart.  The Battery
Minder is a little trickle charger and pulser.  About $45 at $CW$, Northern
Tool, etc.  Larger ones are available from reputable companies on the net.

b) Consumer battery chargers are commodoties.  Adding pulse circuits would add
significant cost.

c) Given the endless combinations of electronics found in cars and the
possibilities for interference from the pulser, and given the woeful technical
ignorance of the typical consumer and given the lawyer plague this country is
currently suffering with, I don't imagine many consumer grade manufacturers
are beating a path toward built-in pulsers.  The one consumer-grade unit that
I know of, the Battery Minder, is such a mild pulser that interference is
unlikely.  That also means it takes weeks to work and probably won't work on
badly sulfated batteries where a more powerful one would.

d) The pulsing won't work in all cases and the instances where it won't are
not yet well defined.  Given the conditions in item C, no one is going to risk
the warranty exposure or the possibility of a "60 minutes" confrontation for a
consumer product.

e) Many of the companies that market battery chargers also market batteries.
It would be very counterproductive to market something that would cut into the
new battery market.

From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Battery Life Saver
Date: Wed, 15 Oct 2003 01:48:18 -0400
Message-ID: <>

The pulse desulphators do work.  Without wasting too much time on this site, I
can just guess how overpriced this thing is, given the hype.  A pulse
desulphator that I've tested extensively in my lab is the BatteryMinder:

This is available from Northern Tool and $CW$ for under $50.  It works as
advertised.  In one test where I took a defunct Group 27 battery that tested
out at under 20 amp-hours on my discharge tester, after 3 weeks of pulsing it
returned to almost 80 amp-hours.  That is while discharging at the C/10 rate.
The recovery leveled off after about 3 weeks.  I should note that the battery
fairly quickly reverted to a deteriorated state when the pulser was removed.
As long as the pulser remained, however, the battery's recovered capacity
remained useable.  That is, the battery could be charged and that much energy
recovered during discharge.

 I'm currently doing a long term test on the device to see if it will prevent
the deterioration of a new battery.  This test will of necessity take several
years.  Stay tuned.

Meanwhile, if you don't want to pay $50 for the device, here is a place to
start for a DIY one.

Lots of good information and plenty of links to elsewhere to follow.  At my
urging a friend recently built the low power pulser described at this site and
has observed better results than with the battery minder.  To be expected,
since the homemade one delivers more energetic pulses than the Battery Minder.
His test was simple:  Old battery would not run his trolling motor before, it
will after.  I'll put it in my computerized discharge tester when he's
finished experimenting and see how well it worked.  Meanwhile my friend is now
in the process of building the high power version.

For more information I suggest scanning the patent database at
Search for "battery desulphator".  There are scads of patents for these
devices, most of the patents involving complications to get around the earlier
patents.  The patents have better than average usefulness as a result.


On Sun, 12 Oct 2003 12:46:05 -0700, "Deano" <> wrote:

>Anybody here ever use this product, "Battery Life Saver" on your RV battery?
>Seems like a pretty good way to extend battery life. Information shows these
>can be used on RV/Marine batteries too.

From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Golf cart batteries
Date: Fri, 02 Dec 2005 14:34:54 -0500
Message-ID: <>

On Fri, 02 Dec 2005 15:13:25 GMT, "Rich256" <> wrote:

>That was just a response to your comment:
>"It requires high voltage for a period of time to break down the
>hard sulfate and get charging current going again."
>I think that is what an equalization charge is all about.  It does what you
>say in bringing back more of the original capacity.

No.  An equalizing charge is designed to bring every cell back to the
fully charged state.  The weaker cells in a string normally limit the
overall charge because they let the voltage rise to the chargers
cutoff (in the case of smart chargers) or regulation point (in the
case of dumb chargers) before the stronger cells are charged.

The cells can be weak for a number of reasons.  Hard sulphate.  Loss
of active material.  Weak electrolyte (from, say, splashing a little
baking soda in the cell during "maintenance").  Maybe a combination of

The hard sulfate only partially obscures the cell's active material.
That's why the cell is weak and not dead.

The stronger cells will gradually become weaker because they never get
a full charge and thus the spongy sulphate has the opportunity to grow
crystals of hard sulfate.

An equalizing charge starts with a nominally fully charged battery. It
consists of a current limited over-voltage charge.  Most of the energy
is dissipated as heat and in electrolyzing water (gassing). The most
fully charged cells gas first, allowing the others to catch up.

 The extended overcharge will convert some/most of the hard sulfate
back into active material.  The vigorous gas evolution in the plates
will open the pores at the expense of shedding some active material.
It won't address weak electrolyte - the owner has to do that after
taking post-equalizing SG readings.

In contrast, a high voltage recovery regime addresses a completely
dead, hard sulfated battery.  When a discharged battery is allowed to
sit, the spongy lead sulfate crystallized to hard sulfate.  Under the
microscope, the surface of the active material looks somewhat like the
inside of a geode.  Crystal sulfate is an insulator so essentially no
current will flow.  One can apply 100 volts or more to a hard sulfated
battery and see very little current flow.

The extended application of high voltage causes a little current to
flow through the cracks and gaps in the sulfate surface.  This flow
cause some of the sulfate to convert back to active material.  This
lets more current flow which in turn converts more material.

This appears to be an exponential process as one would expect.  The
low current slowly ramps up until some point where it quickly rises
toward infinity.

At that point, the battery is still essentially fully discharged but
it is now ready to start accepting a more normal charge.  There is
still a lot of hard sulfate in place so the battery impedance is still
high and it won't accept a lot of current.  Several days' worth of
slow charging is necessary.  A desulfating pulser will speed things

A charger with an "equalizing" mode can be used in this application
because all that equalizing involves is jacking up the voltage while
limiting the current.  But an even higher voltage still greatly speeds
the process.  I've found 24 volts to be a good compromise between
speed and having to watch the thing closely.


From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Battery Questions
Date: Sat, 17 Mar 2007 13:58:51 -0400
Message-ID: <>

On Sat, 17 Mar 2007 10:59:10 -0400, John Kinney
<> wrote:

>I don't know, but Vector recommends the following device for batteries
>which resist reconditioning by the charger itself:

Bad case of trademark infringement.  The REAL Battery Minder costs
under $50 and works.  This infringer probably works too because they
both do the same thing but the trademark infringement certainly is

The Northern link is just for reference.  I'm pretty sure I've seen
this same product for less than $40.  Not to be confused with the same
company's Battery Tender, a charger without the pulser.

And the place to read all about desulfators, buy a kit or build your
own from scratch.

From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: PING NJ  desulfator
Date: Wed, 27 Aug 2008 11:45:58 -0400
Message-ID: <>

On Wed, 27 Aug 2008 08:05:18 -0700, Mickey <> wrote:

>I think this was discussed some time back but not sure.
>What's your take on battery desulfators?  Do they work?
>Don't have time to build one myself so was thinking of a commercial
>unit.  I see they can be had for as little as $25 and go up from there.
>  Any comments on the commercial units?

Yes.  I've tested two.  One is the Battery Minder (or Tender, I can't recall
which is which, anyway, the one with the pushbutton in the center) and one
built from plans from this website that is now deceased. (still available at the Wayback Machine)

This page is still live and has some of his work on it.

Both worked as advertised.

The one that I built is much more powerful than the Battery Minder but the BM
(heheh) does work.  In the test I applied it to an old Group 27 battery that
had been sitting around for a couple of years.  Some folks allege that merely
doing a long term charge will bring 'em back.  After several weeks of sitting
on a dumb charger adjusted to equalize voltage, it tested out at 20 amp-hours
and didn't improve over several cycles.

I put the BM on and left it for a couple of days.  The improvement, if any,
was statistically insignificant.  As I do more often than I should, when I get
an adverse result from an experiment, I tend to walk away, at least for
awhile.  That's what I did in this case.  I shoved the battery with the BM
attached under the bench and forgot about it.

About 3 weeks later I thought about the battery and hooked it to my discharge
tester.  Amazingly enough, it now registered right at 80 amp-hours.
Essentially new.  Most batteries that I've actually discharge-tested have
their capacity over-stated.

I did some more experimenting with the battery and found something curious. As
long as a maintenance charger remained attached, the battery maintained its
capacity.  It could be discharged and recharged as normal.  But if allowed to
sit idle for awhile, it lost much of its recovered capacity.  Not stored
energy but the ability to store energy.  I have no idea why, though I
speculate that maybe the pores in the hard sulfate that pulsing is supposed to
open closed shut again.

In any event, that battery and the one just like it that I tested the
home-made unit on are still powering my UPS as part of a large string of
series-paralleled 24 volt batteries.

Pulse power matters.  The one that I built from plans is much more powerful
than the BM and it did its thing in days.  It's self-powered from the target

You might want to look around and see if you can find a kit based on the
Alastair Couper design.  Most anyone can solder that small of a kit together.
Or heck, have it sent to me and I'll assemble it and send it back.

I've had a BM attached to my house batteries continuously since I ran the
test.  It is not plugged in.  The pulser part works without AC power.  I've
made so many other changes that I can't say if it made any difference or not
but it sure hasn't hurt anything.


From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: desulfator - update
Date: Sun, 28 Sep 2008 13:55:55 -0400
Message-ID: <>

On Sun, 28 Sep 2008 10:35:16 -0500, Bob Giddings <> wrote:

>On Sun, 28 Sep 2008 11:21:12 -0400, Neon John <>
>>>Right now I'm thinking money well spent.
>>Yep.  Thanks for verifying that vendor.  I don't think that I could build one
>>for $25, even using perf board so I'm going to order some.
>The Progressive Dynamics inverter/chargers with the Charge Wizard
>have a desulfator mode built in that charges up to 14.6 V .  Any
>idea how that compares to this one?

That' more commonly known as an equalization charger.  It's designed to
overcharge all the cells a little to make sure the weakest cell is brought up
to full charger - equalization.

When a battery discharges, the sponge lead and lead dioxide on the plates
converts to lead sulfate.  In this form it is a soft spongy matrix of micro
crystals.  The stuff is so soft that it crumbles at the merest touch.

Charging reverses this process if it goes to completion on ALL cells.  The
weakest cell (by that I mean the one with the lowest charge acceptance
efficiency) will typically not have all its lead sulfate converted.  Over time
this residual lead sulfate agglomerates into larger hard lead sulfate
crystals.  These crystals are non-conductive and so insulate the underlying
active material from the electrolyte.  They are also physically larger than
the active material they formed from and so they damage separators and jack
active materials off the plates.  In a badly sulfated battery, the coating of
sulfate looks like frost covering the plate.  Often times sharp crystals of
sulfate can be seen protruding from the plate like little glistening
hypodermic needles.

An equalizing charge stops this process by making sure all cells are fully
charged, that is, all the sulfate is converted.

The pulse desulfator works by a different mechanism that as far as I've been
able to learn, is not fully understood.  It addresses the hard sulfate
crystals that have already formed.  One theory is that the pulses stimulate
mechanical resonance in the sulfate crystals causing them to fracture and
allow electrolyte in.  I'm not too sure of that theory because the crystals
aren't large enough to resonate at the low frequency involved.  That one makes
as much sense as the alternative explanations that I've read, though.  It's
one of those situations where the effect was accidentally observed and now
they're trying to figure out why it works.

From the outside, the battery does look like it has a resonant point.  If a
variable frequency oscillator is connected to a battery and observed with a
scope, when the frequency is swept across the audio band, there will be one or
more frequencies where the battery is resonant.  That is, it much more
strongly absorbs the AC signal than at surrounding frequencies.

The pulse desulfator does its thing by hitting the battery with a series of
narrow, fast rise time high voltage pulses.  Typically 40-60 volts with a
pulse width of around a microsecond, repeated a couple thousand times a

This very fast rising and falling pulse is rich in harmonics and one or more
is the right frequency to stimulate the resonance.

Several things lend credibility to the resonance (of some sort, at least)
theory.  One, the higher the amplitude, the faster the action.  Two, a power
oscillator running at the resonant frequency accomplishes the same thing.
Third, a battery plate that has been pulsed for awhile loses most of its
frosty look.

There are some rather loud-mouthed detractors (not in this group but elsewhere
on the net) who try to claim that extended equalizing charging does the same
thing.  The fly in the ointment for that theory is that most all of the
pulsers available, either ready-made or as kits, are parasitic devices.  That
is, they're powered by the battery being treated.  No external power is
supplied.  Extended high voltage (equalization or above) charging will bring
back some capacity but not to the extent that the pulsers do.

A pulser isn't strictly necessary for a new battery and a competent charger.
However, it doesn't hurt a healthy battery and is there if something happens
to the charger or connections that result in an incompletely charged battery.
Cheap insurance.


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