Hello David
I have done a lot of testing exactly like you have requested for on
AGM and Gel batteries. I had sent the following in a reply
to another group about this same subject. Some of it repeats what you have said.
Any way here is what I have concluded in using many different desulfators.
There are many false beliefs out there about restoring the capacity of lead
acid batteries or resurrecting the dead. Mostly because of a few positive
results that are not based on proper research testing methods. The claims of
bringing dead batteries back or added capacity is used as one of the proofs
these devices work. I could write a 100 pages of all the different ideas
and things I have come across on different web sites. The following is only
about lead acid batteries from testing I have done.
The vast majority start off with a dead battery that will not accept a
charge. The battery is charged with a pulse charger at a very low rate of amps
but high voltage. Most of the time just about all dead batteries will come
back with some life. The problems the battery had before such as a
shorted cell or are just plain worn out are still there. If the battery was fine
before and it was left in an uncharged state the best you can hope for is
some level below what it was. If you take a brand new battery and leave it
uncharged at zero volts. When you fully recharge it will be an unused
damaged battery that diminished capacity. It will never be restored
to a new battery.
Regardless of this many people believe they have
equipment that can resurrect dead batteries or restore them. What is over looked
is you can do this with just about all lead acid batteries by putting them on a
regulated power supply or a float charger. If the battery should at 14.4
volts during charging you set the power supply to 14.4 and .5 amps and watch
until the battery starts accepting a charge. This could take right away to a
month at some point most all batteries will start taking a charge. When the
battery starts accepting a charge a good float charger can finish the charging.
It can take a very long time for a large battery to become fully
charged.
Many people are not aware their batteries are not really fully charged
during regular use. Over charged batteries die but what appears to be
saving the others is many times just bringing a battery to full charge.
Some of these devices pull power from the battery and pulse it. The battery is
supply the power to the desulfator. When the voltage goes down if you have it on
a charger it will come on. This is why some of these devices are not
recommend for vehicles that are not used daily. You would have battery at 10.5
volts until a charge was applied. What they do cause is your charging system to
cycle.
So really what happens after using them is you have a battery
that might show its full voltage but not the amp hours. If you cycle
it a few times you might get a little increase in amp hours but no
miracles. If the battery was in good shape before it might be a
useable battery depending on use. One has to remember many applications do not
involve the heavy demands of and EV. What we want in an EV battery is very
demanding use. Even what we consider the bare minimum might be for someone
else seem about as good as a new battery.
An AGM battery does pick up capacity after being cycled 5 or 10 times
if it is done in a short time frame. This occurs if it has been
maintained properly or left in a discharged state. Some of gains made with
these devices that claim to be restoring your battery are just exercising it by
discharging it and causing the charger to come on and recharge it. There is no
real amp hour gain for an AGM it will go away when the battery sits.
All the results on any successful gains is falsely assumed to be
from using these devices. Some of the web sites claiming they work use
references that at first look legitimate. If you look further though you
will find some use colleges or people that don't even exist. I was not the
first to figure that out there was other posts on different sites that also made
light of this. I still felt the need to full find out about these devices and
the claims made.
I bought several different battery savers. The dead
batteries were of the same make age and condition. At the beginning of the
testing it appeared one or two of the devices might work based on Ah
gains. It was only after the second or third cycle testing did the other
batteries come up and many of them exceed the batteries revived with the
battery savers. I repeated the tests over and over. This was with dozens of
batteries and hundreds of hours of testing with and without using the
desulfators. The results showed there was absolutely no measurable gain that can
be credited to these devices. Someone who just does a battery or two would not
learn this. They would go on thinking they were actually using a device that
works.
I advise you to save your time and money do not buy any of these so called
claimed battery saving devices. I highly recommend a regulated power supply you
can buy on eBay for 40 to 100 dollars. If you want a really high powered one
they cost more and may require 240 volts. Check the supply voltage some are
three phase.
Don Blazer
In a message dated 2/17/2007 8:27:32 PM Pacific Standard Time,
etpost drmm net writes:
On 17
Feb 2007 at 17:50, Neil Dennis wrote:
> My, My, that was quite a
reaction (;-').
Sorry, I don't mean to be overbearing about
this. I've posted comments
about desulfators many times before here,
though, and didn't really say
anything especially different this time
(though I said it perhaps more
succinctly or more bluntly).
Let's
try it this way.
Suppose you're down by the dock, cussing about your
boat's battery. It's a
few years old, and you're finding that it
won't run the lights long enough.
It's supposed to be a 120 amp hour
battery, but you can use only about 30
amp hours before the lights start
getting dim. If you try to run the
trolling motor, the lights almost
go out, and the motor barely runs.
I walk by and hear you
complaining. I stop and tell you, "You have a
sulfation problem. I
have a gadget that will fix that. This is a
desulfator. It
reverses sulfation. It can recover some of your battery's
old zip -
not all of it, mind you, but some. Now, if you'd been using it
from
the time the battery was new, your battery would still be almost like
new. Use it on your next new battery, and when it's this old, it
will still
be good enough to run your lights and motor."
It's a
deal. I leave with $69.95 in my pocket, and you have a nice little
black box. It has an AC cord and a wire with clips for the
battery.
There's a little blinking LED on it.
I told
you to hook this black box up to the battery and leave it plugged in
for a
few days, to get back some of the tired old battery's capacity. And
when you get a new battery, you should use it for 12 to 24 hours about
once
a month, to keep the battery in tip-top shape.
So you try
it. Lo and behold, you run it for 3 days and you now have 40 amp
hours. You run it another 3 days and you have 50 amp hours.
Another week,
and you're up to 60!
Ah, but it doesn't last. A
month later you're back to 25 amp hours of
capacity. So you bite the
bullet and buy a new battery. This time, you
hook up my gadget once
a month for 24 hours, just as I suggested. When this
battery is 3
years old, you have almost 100 of your original 120 amp hours
of
capacity. It works!
What did it do?
In a brand new
battery, not all the cells are exactly the same. There's
always one
that has a little less capacity. Each time you charge the
battery,
that's the last one to get full. Sometimes it doesn't quite get
there. If this happens too often, that cell really does begin to
develop
permanent sulfation, but that's not what kills it.
The capacity of your battery is determined by that weakest cell.
When that
weak cell goes dead, its electrolyte is essentially water.
Its internal
resistance goes way up. Even if the other cells still
have some charge
left, they can't push any decent amount of current
through the resistance of
the dead cell. So you can't get much
useful work from the battery. But
many times you keep trying to use
the battery for a while. It can still
light the lights for some time
longer, even if dimly.
When you do this, you're forcing current
through that dead cell. This
charges it backwards. This is
called cell reversal, and it's very damaging.
Repeated reversal is what
really kills the cell. Its capacity takes a
dive, and now you have a
30 amp hour battery when it used to be 120 amp
hours.
When you
connected my "desulfator," it forced current through the good cells
(in
the right direction!) to give the bad one as much charge as it could
possibly hold.
You also helped the battery yourself, just by
taking an interest in it. You
cycled it more often than you usually
did. Exercise for batteries is like
exercise for humans - it
improves their stamina. This helped to temporarily
build up its
capacity. That's why it rose from 1/4 to 1/2 its new
capacity.
But then you went back to your old usage patterns, and the
battery went back
to its old capacity.
In using my "desulfator" on
the *new* battery, you were performing a regular
equalization on the
battery. This kept the inevitable weak cell fully
charged,
preventing it from being reversed as frequently. You kept the
battery fit and useful longer.
So I sold you a gadget that fixed
your "sulfation problem." I told you it
would reverse sulfation -
and it did. I told you it would give your battery
more capacity -
and it did. I told you it would keep a new battery fit
longer - and
it did. You're happy, and I'm $69.95 richer. What's the
problem?
What I sold you was a battery charger with a blinking
LED. Did I cheat you?
No. I said it would reverse sulfation,
and that's exactly what a battery
charger does - that's how a battery
charges. I said it would add some
capacity to your old battery, and
an equalizing charge applied with a
battery charger will do that. I
said it would help a new battery last
longer, and equalization applied at
the proper intervals will do that, too.
Equalization brings up weak
cells to get the maximum possible capacity out
of an old battery, and
prevent damage to weak cells in a new battery.
I didn't make any claims
about "crystal resonance," even though some
desulfator adherents try to do
that. Here's one example : "A desulfator
works by creating a
resonance frequency that cause the sulfur ions in the
batteries to
dissolve back into the electrolytic solution of the battery."
An
electrochemist - an engineer who designs batteries - will tell you that
such claims are nonsense. I suspect that the people who developed
pulse
desulfators years ago found that they helped batteries, and they
groped
around until they found something that seemed to explain (at least
to their
satisfaction) what the gadgets were doing.
Desulfators have a small but very avid and vocal corps of
believers. And
they are right, in a sense - the gadgets do
work. But so would a cheap
little trickle charger, for about
one-third the price. Or the charger you
already have.
What I really sold you back there on the dock, for $69.95, was $19.95
worth
of charger and $50 worth of advice - that equalizing your battery
regularly
would maximize its capacity and keep it healthy.
But you could have gotten that advice for free - right here, in any
number
of good battery books in the library or at the bookstore, or on the
web.
I sold you something you could have - should have - gotten
for free. Am I a
crook, or an entrepreneur?
For years I've
been asking folks who sell desulfators, and those who are
sold on them, to
perform a real test. I want them to use two batches of
essentially
identical batteries, applying the desulfator to half and a
decent
equalizing charger to the other. Treat the batteries exactly the
same except for what's charging them, and see if one group behaves
significantly differently.
I think that's a reasonable
request. It isn't 100% conclusive, but if their
desulfator is really
better than an ordinary charger, it should show up in
statisically
significant, consistently improved performance in the group
treated with
the desulfator.
So far no one has taken me up on it. Any
idea why not?
David Roden - Akron, Ohio, USA
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