recharging alkaline batteries
James C. Xi'an
I apologize in advance if this is not the proper forum for this
discussion:
I recently caught a late-night infomercial hosted by Dick Clark
about a recharger for common alkaline batteries. The claim was
that the recharger not only recharges common alkaline batteries
but also extend their lives by almost 10 times. Because this is
not my field, this claim raised one question in my mind:
How can one decrease the battery discharge rate from the norm?
(I assume the capacitance of the battery is not changed after
recharging.) Or, if the fact is that the battery makers do not
charge the batteries up to their full capacities, and the recharger
does; then what is the full capacity of the normal alkaline batteries?
The recharger was said to be built by a Professor Pfeiffer(sp?) of
McGill University of Canada. Can anyone up there verify this?
Thanks for any reply.
James
Stewart T Fleming
There was a similar report in the UK quite recently. The proponent
of the idea works for a catalogue known here as _Innovations_,
which sells techno-novelty devices. The claim is that ordinary
alkaline batteries can be recharged. Manufacturers state that
doing so can be dangerous, leading to explosive cell separation.
The basis of the claim for recharging ordinary alkaline batteries
is int he use of a microprocessor to closely monitor the charge level
and to adjust the charge rate accordingly. This is done to prevent the
potentially-explosive build-up of gases within the cell. The charging
process is reported to be otherwise the same as for nicad rechargeables.
This was reported in a feature article in the _Independent_ national
newspaper in the UK fairly recently. I don't have more details than that.
STF
--
sfle...@cee.hw.ac.uk, sfle...@icbl.hw.ac.uk
"Ride bike, no limit."
Rey Andrada
>
>There was a similar report in the UK quite recently. The proponent
>of the idea works for a catalogue known here as _Innovations_,
>which sells techno-novelty devices. The claim is that ordinary
>alkaline batteries can be recharged. Manufacturers state that
>doing so can be dangerous, leading to explosive cell separation.
this weekend i saw an ad on tv about this charger invented by a certain
proffesor from a Canadian University and it goes for $40.00.
rey
Michael Schuster
Stewart T Fleming <sfle...@cee.hw.ac.uk> wrote:
>
>There was a similar report in the UK quite recently. The proponent
>of the idea works for a catalogue known here as _Innovations_,
>which sells techno-novelty devices. The claim is that ordinary
>alkaline batteries can be recharged. Manufacturers state that
>doing so can be dangerous, leading to explosive cell separation.
>
>The basis of the claim for recharging ordinary alkaline batteries
>is int he use of a microprocessor to closely monitor the charge level
>and to adjust the charge rate accordingly. This is done to prevent the
>potentially-explosive build-up of gases within the cell. The charging
>process is reported to be otherwise the same as for nicad rechargeables.
Some microprocessor-controlled nicad chargers have an algorithm designed
to prevent the buildup of gas. Periodically during the charge cycle,
the cell/battery is allowed to discharge at a very high rate, for
a few milliseconds (not enough to significantly undo the charge thus far).
I wonder if this technique is used in the alkaline cell charger we've
been hearing about.
--
Mike Schuster | schu...@panix.com | 70346...@CompuServe.COM
------------------- | schu...@shell.portal.com | GEnie: MSCHUSTER
wallace.r.blackburn
>In article <1993Aug17....@cee.hw.ac.uk>,
>Stewart T Fleming <sfle...@cee.hw.ac.uk> wrote:
>>
>>There was a similar report in the UK quite recently. The proponent
>>of the idea works for a catalogue known here as _Innovations_,
>>which sells techno-novelty devices. The claim is that ordinary
>>alkaline batteries can be recharged. Manufacturers state that
>>doing so can be dangerous, leading to explosive cell separation.
>>
>>The basis of the claim for recharging ordinary alkaline batteries
>>is int he use of a microprocessor to closely monitor the charge level
>>and to adjust the charge rate accordingly. This is done to prevent the
>>potentially-explosive build-up of gases within the cell. The charging
>>process is reported to be otherwise the same as for nicad rechargeables.
>
>Some microprocessor-controlled nicad chargers have an algorithm designed
>to prevent the buildup of gas. Periodically during the charge cycle,
>the cell/battery is allowed to discharge at a very high rate, for
>a few milliseconds (not enough to significantly undo the charge thus far).
>I wonder if this technique is used in the alkaline cell charger we've
>been hearing about.
>
Considering it is only $40, I can't believe noone on the net has bought
one! How about it? Does anybody have on of these things yet? If so, HOW
DOES IT WORK? (I don't mean how does it do what it does, I mean does it
REALLY recharge alkaline batteries or not).
What? Me? I'm not wasting 40 bucks on one of those things!
--
+===============================+ Happy user of OS/2 2.0!
| Wally Blackburn | Ask me about it!
Gary Coffman
The alkaline battery uses a primary cell chemistry. It can't be
recharged in the manner of a secondary cell chemistry such as
lead-acid or NiCd because the reactions aren't reversible. What
this device actually attempts to do is *depolarize* the cell with
a small reverse current. This allows more of the primary chemicals
to react. It should more accurately be called a *rejuvenator* rather
than a recharger.
A primary cell generates current by *irreversibly* consuming
it's reactants. Because of certain subtleties in the chemical
reaction paths, the surfaces of the reactants can become
passivated during discharge. This effectively stops the reactions,
and the electrical current production. "Long life" batteries
use an additional chemical in the cell to attempt to do much
the same depolarization without external current. By feeding a small
reverse current through the cell, however, it's often possible
to temporarily strip this film off the reactants much more
effectively and allow the reactions to continue for a while
longer. That's what the Buddy-L does.
The infomercial was vague to the point of deception about this
as can be seen by your confusion about the unit *both* recharging
the cells *and* extending their lives by almost ten times. That's
not what the fine print in the disclaimer actually says. What it
does is *depolarize* the cell up to ten times allowing you to use
up more of the reactants in the cell. There's a very real danger
here of letting the reaction eat through the outer casing, one
of the reactants, by this life extension technique. That will
release corrosive chemicals into your equipment. That's one of
the reasons that battery manufacturers caution you not to
attempt to "recharge" primary cells. The other is risk of
explosion since primary cells *can't* be recharged and can
get very hot and build up high gas pressures if reverse currents
are forced into the cell. The Buddy-L minimizes this risk by
limiting current flow to a very low value.
The Buddy-L is not worthless for certain types of primary cells,
but the infomercial is very deceptive in it's presentation. It
is *not* a charger in the technical sense.
Gary
--
Gary Coffman KE4ZV |"If 10% is good enough | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems | for Jesus, it's good | uunet!rsiatl!ke4zv!gary
534 Shannon Way | enough for Uncle Sam."| emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244 | -Ray Stevens |
Filip Gieszczykiewicz
> I recently caught a late-night infomercial hosted by Dick Clark
>about a recharger for common alkaline batteries. The claim was
>that the recharger not only recharges common alkaline batteries
>but also extend their lives by almost 10 times. Because this is
>not my field, this claim raised one question in my mind:
Greetings. I seem to recall that some reader of this group has
a signature which states: "You make it, we break it, guaranteed"
.... If you agrees, we could all donate a few bucks each (not
everyone... an no one will grimace if you don't) for a fund to
have him (or some other person who works in that field) to test,
destroy, and write up a short summary of "their opinion".
I think this would be money VERY well spent... As long as the
person who does the testing is qualified, many people will
benefit... I'm not sure what one of these labs charges for a
"test" but if it's anywhere near reasonable (or someone volunteers
some time of their own to cut the cost a bit), something could be
worked out.
If not that, how about giving people incentive to write reviews
and articles on their experimentaion with recent-release gizmos.
I don't think money will be simple due to taxes, EEs being poor,
and family reasons but how about "objects". I have a few megs of
SIMMs that I could part with for a good cause, etc. If only enough
people would... [sigh]
Anyways, just a though... feel free to stomp on it.
Take care.
--
+--> Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmg...@pitt.edu"
| If you would like to receive the latest version of the SCI.ELECTRONICS FAQ,
| E-mail me and I will send you the INDEX to confirm address. Feedback Welcome!
| I live for my EE major, Windsurfing, SCA, programming, and assorted dreams.