# [EVDL] Battery desulfation



## EVDL List (Jul 27, 2007)

This appeared on the electric boats list. I found it interesting and
seems to validate the approach (which has been poo pooed here in the
past)
In June, 2000 a fellow by the name of Alastair Couper published the
first desulfator designed for home use in Home Power magazine. He
created a BBS, which still exists today for home experimenters. I am
a moderator of that board (desulfator2). I have uploaded the original
Home Power article to the files section.

http://leadacidbatterydesulfation.yuku.com/

Since then, 95% of the desulfators on the market are copies or
derivatives of that original design. They use a modified buck and
boost (inductive flyback) circuit that pulses the battery. They tend
to have a recovery rate of about 1-2 pounds of battery per day.

Since 2000, I have continued to research faster methods of
desulfation. I had a breakthrough in 2005 when I was contracted to
design a fast desulfator for a US Air Force communications facility.
I provided 3 prototypes. The last one was the charm and desulfated a
400 pound battery in record time (3 weeks). Since then I have doubled
the desulfation rate. This summer or fall I plan on prototyping a
more powerful design.

Sooooooooooo, I've had no interest in other designs, preferring to
continue research ever faster pulser designs. Some years ago I
managed to accidently desulfate a pair of L-16's in about 10 seconds.
The results were poor as the sulfates were literaly blown off of the
plates and the batteries were ruined in the process. But, it taught
me some important lessons about the path to take. 

It is one of the reasons I have an interest in electric boats. I know
that lead acid batteries can last longer than 30 years if properly
maintained. The trick is to keep them from getting sulfated.
Permanent damage only occurs from cycling a sulfated battery or too
heavy charge/discharge currents. Since batteries can be cheaply
recharged they seem an ideal marine drive power source for weekend
boating.


-- 
http://www.austinev.org/evalbum/1059
http://stormselectric.blogspot.com/
Storm

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## EVDL List (Jul 27, 2007)

So in your samurai conversion, which is pretty slick by the way

this is the only pic of the desulfator?

http://picasaweb.google.com/stormconnors/SuzukiEV#5186548277220329026

And on your website the only technical info I could find was none, but kits
were for sale...

Is this email to the list a subtle commercial advertisement?



> storm connors <[email protected]>wrote:
> 
> > This appeared on the electric boats list. I found it interesting and
> > seems to validate the approach (which has been poo pooed here in the
> ...


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## EVDL List (Jul 27, 2007)

> On 16 Jun 2010 at 7:43, Cole wrote:
> 
> > Is this email to the list a subtle commercial advertisement?
> 
> ...


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## EVDL List (Jul 27, 2007)

I think #2 is a bit too strict, but not by much. Maybe we should add an exception for the initial introduction of a new product.
I know exactly why it was written, We don't want the list full of ads, ads for the same thing over and over again. I for one would
like to know about new products, as long as the mention strictly follows the other rules. (of course you can always just ask a
friend to ask about it on the list for you)



> > On 16 Jun 2010 at 7:43, Cole wrote:
> >
> >> > Is this email to the list a subtle commercial advertisement?
> > Announcing and discussing products on the list isn't prohibited, as long as
> ...


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## EVDL List (Jul 27, 2007)

> EVDL Administrator wrote:
> 
> > On 16 Jun 2010 at 7:43, Cole wrote:
> >
> ...


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## EVDL List (Jul 27, 2007)

We need to consider all the modes of failure.

Chemical and Mechanical.

To my knowledge Sulfation is only one form of failure, a pre-mature chemical form of failure. Which leads to the possibility of it's
reversal.

But the normal service life of a Pb-A battery is from the conversion of plate material into lead dioxide, loss of base grid material
and irreversible mechanical plate damage. It "wears out". This is the know form of end of service life.

There are batteries with thicker plates and a deep sump to capture the material shed without shorting cells desigened to last 25
years. But... You would not want to use Pb-A batteries with the 25 year design in your EV, The Wh/kg is impractical. Maybe in a boat
or submarine, but not in a car.

Of course the other mode of pre-mature failure which is for sealed batteries is "dry-out".

So while I may listen to claims of success for desulficators as a partial restoring of pre-mature sulfation. I stop listening and
classify as scam as soon as they claim the categorical and impossible "I know that lead acid batteries can last longer than 30 years
if properly maintained"


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## EVDL List (Jul 27, 2007)

Schematics and build notes are also freely available on the website. 
Details of how long/hard to hit the batteries is a bit sketchy, but there 
are lots of testimonials.

I personally thought this was an FYI for the DIY crowd.

-Adrian



> Roger Stockton wrote:
> 
> > EVDL Administrator wrote:
> >
> ...


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## EVDL List (Jul 27, 2007)

I have used a pulse desulfation charger and it did work on several
batteries, especially old car batteries. About 3 years ago I had one that
would not charge at all, and after two days on the desulfator cycle it
recovered enough to be useful. It then would take a full charge and is still
in use. I also use it on my sealed AGM batteries ( Concorde 100Ahr ) in my
RV and they are lasting 4-5 years. Before that I got only 2-3 years. I am
doing it on my 2005 Volvo battery every six months and it is still fine.
Since the principal and circuits are in public domain now and also it does
not do anything negative why not just try it and see. It seems that using it
for ev Pb's would be a good way to find out how well it works for this kind
of use.

-- 
When all else fails, remember failure is the success of knowing what not to
do.-3
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## EVDL List (Jul 27, 2007)

> On 17 Jun 2010 at 13:06, ron doctors wrote:
> 
> > I have used a pulse desulfation charger and it did work on several
> > batteries, especially old car batteries.
> ...


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## EVDL List (Jul 27, 2007)

> EVDL Administrator <[email protected]>wrote:
> 
> > . And from what I can see, the
> > "desulfators" are, effectively, little more than trickle chargers.
> ...


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## EVDL List (Jul 27, 2007)

As I have told this list before, my personal experience with a discharged
12V. ISA battery was a long trickle charge at a constant voltage of 13.6 v.
@ 1 to 2 A. brought several batteries back with a 14 day effort each but
only 2 were OK, out of 5 and 3 were recycled.
Regards,
Dennis Miles
---------------------------------------------------------------------------=
--------------------------------------------------


> Zeke Yewdall <[email protected]> wrote:
> 
> > On Fri, Jun 18, 2010 at 12:23 PM, EVDL Administrator <[email protected]
> > >wrote:
> ...


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## EVDL List (Jul 27, 2007)

Battery "desulfators" is a concept based on misunderstanding and lack of
knowledge.
Lead Acid batteries do not develop any hard sulfation under normal use
conditions (to be "desulfated") when properly charges and discharged. 
Hard sulfation occurs only if they are operated in a partially charged
condition and /or left unattended for several months without boosting. 
Lead dioxide (a metal oxide) on the positive plates reacts very slowly
(because of the passivation phenomenon) with sulfuric acid to form lead
sulfate (just as it does during a normal discharge, which is at a many folds
higher rate) Forming relatively larger lead sulfate crystals. Lead sulfate
does not conduct electrons, so the large sulfate crystal have a hard time
converting back to lead dioxide. This, however is a pathological condition
which can sometimes be reversed by trickle charging. 
As I mentioned earlier, normally this condition does not develop if the
charging / boosting is done properly.

So beware of so called "desulfators".

Actually, you can take a junk / dead battery and give it a severe charge at
constant current (with or without the "desulfators"), the chances are that
it will look like it has come back from the dead. Unfortunately, this leads
the tinkerers to falsely believe in their invention. However, the battery
dies very soon thereafter again.

Remember the lead acid battery active materials must form lead sulfate to
work: Lead dioxide to lead sulfate on the positive and spongy lead to lead
sulfate on the negative during discharge. During the following normal charge
the sulfate formed this way easily converts back to the original active
materials because of the size of the crystals which permit the dissolution
reprecipitation reaction. 

Nawaz Qureshi
VP of Engineering and Technology

[email protected]
T: 951-371-8090
Fax: 951-371-4671

Making the simple complicated is commonplace; making the complicated simple,
awesomely simple, that's creativity - Charles Mingus





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Message: 1
Date: Fri, 18 Jun 2010 15:04:42 -0400
From: Dennis Miles <[email protected]>
Subject: Re: [EVDL] Battery desulfation
To: Electric Vehicle Discussion List <[email protected]>
Message-ID:
<[email protected]>
Content-Type: text/plain; charset="windows-1252"

As I have told this list before, my personal experience with a discharged
12V. ISA battery was a long trickle charge at a constant voltage of 13.6 v.
@ 1 to 2 A. brought several batteries back with a 14 day effort each but
only 2 were OK, out of 5 and 3 were recycled.
Regards,
Dennis Miles
----------------------------------------------------------------------------
-------------------------------------------------

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## EVDL List (Jul 27, 2007)

Thanks much for the analysis, Nawaz. We always appreciate it when you weigh 
in on battery issues here.

For those who don't know, Nawaz has been on the EVDL for many years, since 
the days when he was a senior electrochemist at US Battery. (He is now vice 
president of engineering there.)

David Roden - Akron, Ohio, USA
EVDL Administrator

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## EVDL List (Jul 27, 2007)

Nawaz,
Thanks for explaining the physical chemistry involved in recharging and
"De-sulphation by trickle charging." I try to share my successful techniques
with the "Newbys" when I am able, and it sure feels NICE to have an EXPERT
like YOU say I am doing it correctly.
Regards,
Dennis Lee Miles (Director) E.V.T.I. inc.
www.E-V-T-I-Inc.COM (Adviser) EVTI-EVA Education Chapter
Phone (863) 944 - 9913
It=92s estimated that the existing U.S. electrical grid has sufficient
capacity to fully fuel three-quarters of the nation=92s 217 million passeng=
er
vehicles.
---------------------------------------------------------------------------=
----------------------------------------------------
On Mon, Jun 21, 2010 at 1:09 PM, Nawaz Qureshi <[email protected]>wrot=
e:

> Battery "desulfators" is a concept based on misunderstanding and lack of
> knowledge.
> Lead Acid batteries do not develop any hard sulfation under normal use
> conditions (to be "desulfated") when properly charges and discharged.
> Hard sulfation occurs only if they are operated in a partially charged
> condition and /or left unattended for several months without boosting.
> Lead dioxide (a metal oxide) on the positive plates reacts very slowly
> (because of the passivation phenomenon) with sulfuric acid to form lead
> sulfate (just as it does during a normal discharge, which is at a many
> folds
> higher rate) Forming relatively larger lead sulfate crystals. Lead sulfate
> does not conduct electrons, so the large sulfate crystal have a hard time
> converting back to lead dioxide. This, however is a pathological condition
> which can sometimes be reversed by trickle charging.
> As I mentioned earlier, normally this condition does not develop if the
> charging / boosting is done properly.
>
> So beware of so called "desulfators".
>
> Actually, you can take a junk / dead battery and give it a severe charge =
at
> constant current (with or without the "desulfators"), the chances are that
> it will look like it has come back from the dead. Unfortunately, this lea=
ds
> the tinkerers to falsely believe in their invention. However, the battery
> dies very soon thereafter again.
>
> Remember the lead acid battery active materials must form lead sulfate to
> work: Lead dioxide to lead sulfate on the positive and spongy lead to lead
> sulfate on the negative during discharge. During the following normal
> charge
> the sulfate formed this way easily converts back to the original active
> materials because of the size of the crystals which permit the dissolution
> reprecipitation reaction.
>
> Nawaz Qureshi
> VP of Engineering and Technology
>
> [email protected]
> T: 951-371-8090
> Fax: 951-371-4671
>
> Making the simple complicated is commonplace; making the complicated
> simple,
> awesomely simple, that's creativity - Charles Mingus
>
>
>
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 18 Jun 2010 15:04:42 -0400
> From: Dennis Miles <[email protected]>
> Subject: Re: [EVDL] Battery desulfation
> To: Electric Vehicle Discussion List <[email protected]>
> Message-ID:
> <[email protected]>
> Content-Type: text/plain; charset=3D"windows-1252"
>
> As I have told this list before, my personal experience with a discharged
> 12V. ISA battery was a long trickle charge at a constant voltage of 13.6 =
v.
> @ 1 to 2 A. brought several batteries back with a 14 day effort each but
> only 2 were OK, out of 5 and 3 were recycled.
> Regards,
> Dennis Miles
>
> -------------------------------------------------------------------------=
---
> -------------------------------------------------
>
> _______________________________________________
> | REPLYING: address your message to [email protected] only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
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> | OPTIONS: http://lists.sjsu.edu/mailman/listinfo/ev
>



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## EVDL List (Jul 27, 2007)

Can you see these large sulfate crystals?

Is there some other way to tell a battery has been permanently 
damaged from not fully charging or leaving partially discharged?




> Nawaz Qureshi wrote:
> 
> > Forming relatively larger lead sulfate crystals. Lead sulfate
> > does not conduct electrons, so the large sulfate crystal have a
> ...


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## EVDL List (Jul 27, 2007)

> Nawaz Qureshi <[email protected]>wrote:
> 
> > Lead Acid batteries do not develop any hard sulfation under normal use
> > conditions (to be "desulfated") when properly charges and discharged.
> ...


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## EVDL List (Jul 27, 2007)

Yes, one can see the large lead sulfate , electrically insulated areas, in
an SEM (scanning electron microscope) magnification in a badly sulfated
plate. In severe conditions, the normally 

To see if this kind of sulfation has occurred, all of the following are
observed:

1. The hydrometer readings are low, i.e. discharged SG.
2. The open circuit Voltage is lower than normal, and will read the Voltage
of a discharged battery. Normal OCV is 2.1 Volts or higher per cell in a
charged battery. 
3. Most importantly, when you charge the battery all cells will gas without
returning any substantial capacity. (In a normal end of life failure, when
one or more cells have developed internal shorts, these bad cells will not
gas or gas much less towards the end of charge).
4. After giving it a normal charge, it will only deliver a fraction of the
original capacity.

Again, sometimes (but not always) this condition can be healed with trickle
constant current charging (1 to 3 Amperes) for several days. An alternative
cure is to give it many charge discharge cycles if it will deliver any
capacity. The healing success depends upon how badly sulfated they are. 

Incurable sulfation happens if you let the batteries sit around unattended
for six months to a year, less at colder temperatures and , more severe at
warmer temperatures. Also, by operating them in an undercharged condition.
The unconverted lead sulfate crystals act like seeds on which the
undesirable larger crystals tend to grow. 

Cold storage will extend the stand life. 

If one boosts the batteries every six weeks or so, they will not sulfate. Or
if you leave them on float Voltage (about 2.2 VPC) they will not self
discharge as it overcomes the self discharge by accepting a trickle current
and cannot harm the batteries. Floated batteries can be stored for many
years without any serious degradation. Periodic boosting is a short time
charge to bring them up to full charge. 


Nawaz Qureshi
VP of Engineering and Technology

[email protected]
T: 951-371-8090
Fax: 951-371-4671

Message: 23
Date: Mon, 21 Jun 2010 22:02:08 -0400
From: "John O'Connor" <[email protected]>
Subject: Re: [EVDL] Battery desulfation
To: Electric Vehicle Discussion List <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed

Can you see these large sulfate crystals?

Is there some other way to tell a battery has been permanently 
damaged from not fully charging or leaving partially discharged?




> Nawaz Qureshi wrote:
> 
> > Forming relatively larger lead sulfate crystals. Lead sulfate
> > does not conduct electrons, so the large sulfate crystal have a
> ...


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