Today, in a hurry, I went into a Rite-Aid to buy a battery.
I needed a 9-volt for an electronic tuner.  Usually I buy
batteries in the checkout lane of either Target or Krogers,
so I tend to not pay attention to how much they cost.  But
when buying just the battery the price kinda just stood there,
staring me down - $3.49.  We're talking one battery.

Naively I asked if maybe Energizer batteries were less than
the Duracell.  Nope.  So then I got to thinking about non-alkaline
batteries which are something like two for $1.39.  And what about
rechargeable batteries?

What is the difference between alkaline and "classic" batteries?
Is one more prone to leakage?  Why the big difference in cost?
Are rechargeable batteries cost effective and better for the
environment?

75 responses total.

Alkaline are supposed to last longer.

Rechargeables do not last as long on a charge as non-rechargeable.

re #1 Yes but you can recharge them *hundreds* of times at least the
nickle cadmium.  Much cheaper and better for the environment in the long
run.  The best place for rechargables is rat shack. 

Alkaline batteries keep a nearly constant voltage as they are used while the
"classic" batteries drop in voltage as they are used.  Also the Alkaline
batteries have a significantly longer life than the "classic" batteries.

As an example, if you had two flashlights, the one with Alkaline would outlast
the one with "classic".  Also the alkaline batteries would burn at a contstant
bright level for the the life of the battery then they would die with very
little warning.  The one with classic batteries would begin to dim after a
relatively brief use and keep on getting dimmer and dimmer.  If you shut this
one off for a while, it would regain and be bright initially, but it would
rapidly dim again.  This one has a point where it is so dim, you will get rid
of it.  

I don't know the cost effectiveness of rechargables, but I believe they
probably are a good deal.  I think their "service life" after a charge may
not be anywhere near as long as an alkaline battery, so they may not be the
best for some uses.

Oh, the "shelf life" of alkaline batteries is far superior to that of
"classic" or zinc-carbon batteries.  I believe alkaline batteries discharge
at higher rates than other batteries and may be preferred for certain
applications such as photoflash.

Batteries?  What are those?  Oh, you mean those large things that you put in
your notebook so that after it's been plugged in for a while, you can use it
without a power cord?  Or maybe those heavy monsters that start your car? 
"Stick to a power cord.  It has the longest service life on one charge." I
always say. :)

IMNSHO, 9-volt batteries suck!

I generally use NiCad rechargables, since they are much cheaper in the 
long run.  However, some applications with very low power use (such as 
electronic tuners) can use just about anything.  Things that draw a lot 
of power, such as CD players or Newtons, work *great* with NiCads.

Rayovac makes a "reusable alkaline" called "Renewal", but it hasn't 
proven to be very effective.  You get maybe 10-20 times the life of a 
normal alkaline with the special charger.  These are good for things 
like small flashlights, and would probably be great for electronics if 
they made a 9v version.  I found enough weak cells in the ones I used to 
sour me on the concept, though.

  Ok. Radio Shack is the cheapest on batteries, and they have always performed
very well for me. I will recommend them on my reputation.

  As for Ni-Cads- I have 2 nicad batteries that power my Icom 2m handheld
radio. I have had them for about 7 yrs, and both show no signs of slowing
down-- I bought these on the word of Steve Andre, you may have heard of this
person who has been known to carry an excess number of radios with him.
  The above batteries were procured from W&W associates of Queens NY, and 
I believe they even have a toll free number. If you're going to go Ni-Cad,
call them, because if they do not have your battery, they will find it.

  Don't buy zinc-carbon batteries. They are useless. Buy only alkaline.

Omni is right. Alkalines are the best kind of non-rechargeables. The last
pack of 9-volt alkalines I bought from Radio Shack cost 4/$7 - *but*, they
have periodic sales at 3 packs for the price of 2. That makes a 9-volt
battery cost $1.18. Stock up: alkalines also have a long shelf life (as well
as having a higher capacity/weight).

NiCads are the best low-weight rechargeables currently. I also use them in
amateur radios, as does omni. I've had very good life from them. As mentioned,
they have very high current capacity - they are built into "Dustbusters"
(and you can replace them yourself). Don't leave nicads on charge for long
times, and they need to be discharged to ca. 1 volt each periodicially (but
never totally discharge them). The best prices for NiCads are via mail order.

Actually, I consider the Panasonic NiCads to be about the best consumer NiCads
that I have used, and the price is good.

I think that the radio batteries that omni refers to are special "packs"
designed for his model radio.

I use mostly NiCads, but NiCads give less power than Alkalines.  (Like a AA
NiCad may give 1.3 or 1.4 volts instead of 1.5).  Some products (like my
digital camera) won't work on them (actually I have some "Golden Power" NiCads
tha work with the camera, but my Panasonic NiCads don't have enough power).
Since I have some stuff that seems to need alkalines, I have a fancy charger
that does both alkalines and NiCads.  Yes, with the right technology, you can
recharge alkalines.  It takes a long time, and has to be done with care but
it works.  Alkalines recharge best if you don't run them down, just "top them
off" regularly.  NiCads have the longest life if you do discharge them between
use.  The charger I have discharges NiCads before recharging them, and for
either type of battery, automatically shuts off when the battery is fully
charged (over charging can be a problem).

Re # 7,9: I use 8 individual NiCads in a battery pack for a hand held
transceiver. Advantages of this are lower replacement cost and ability to
replace single cells (though I have not had to over several years).

You cannot *recharge* alkalines. The chemical reaction is not reversible.
What "recharging" does is depolarize the battery - it redistributes some
of the reaction products so that they do not interfer as much with the
desired reactions. (I am not referring to specifically "rechargeable
alkalines" - I don't yet know their chemistry.)

  Scott, while it is true that my NiCads are made for my radio, the point was
that W&W will provide any NiCad that you may need, and you might want to go
there instead of Meijer, or Target.

Yes, omni, unless the mail-order shipping/handling charges wipe out the lower
prices.

i have seen a few ads for chargers which supposedly work with single-use
alkaline batteries, but i have no info on performance.

Oh yes - they are sold. And they are 'panned' by Consumers Reports, and in
newsgroups. Renewals are apparently a bit better, but they lose capacity
on *every* charge. I suspect that they are real;y alkalines that are designed
for more efficient depolarization.

would you please elaborate on the "depolarization" mechanics for those of us
less knowledgeable in the matter?

  I think what Rane is trying to say is that the chemicals inside the battery
somehow meld into one big sludge, thus discharging itself in the process.

 I hope this is on the right track.. ;)

Well, not bad for a ham.. 8^}... The electrodes in an alkaline battery are
powdered zinc (Zn) at the anode (-), and powdered manganese dioxide (MnO2) 
at the cathode (+). During discharge, the reactions at each electrode are

  anode               2Zn  +  8(OH-)  =  2Zn(OH)4(-2)  + 4e(-1)
  cathode    3MnO2  +  4e(-1) + 2H2O  =  Mn3O4  +  4(OH)(-1)

where (OH)(-1) is the hydroxide ion, Zn(OH)4(-2) is the zincate ion,
Mn3O4 is manganese tetroxide (solid), and e(-1) are electrons.

As the discharge proceeds, (OH)(-1) is consumed at the anode, reducing its
concentration. Fresh (OH)(-1) must diffuse in from the center of the cell
to replace it. This is a slow process, so the depleting (OH)(-1) reduces
the cell voltage. Likewise, at the cathode, OH(-1) is produced, also diffuses
slowly, and accumulates, also reducing the cell voltage. The decrease of
(OH)(-1) at the anode and its increase at the cathode is called concentration
polarization. How can this be reduced?

If we apply a reverse current through the cell the anode reaction tends to
reverse, but it cannot, as hydrogen will be produced instead of zinc.  The
cathode reaction also tends to reverse, but both MnO2 and oxygen are
produced there. However throughout the battery during "recharging" the
current is carried by (OH)(-1) ions, *removing* them from the cathode
electrode vicinity and building them up again at the anode electrode
vicinity. The current reduces the concentration polarization. Neither zinc
(Zn), or manganese dioxide (MnO2)  completely are reformed, so the battery
is not really being recharged. You just recover some of the "kick", but
not the active ingredients (Zn and MnO2). 

thank you.

I also prefer NiCad and Alkalines.  When carbon / zink batteries die
they start leaking a very corrosive goo that will eat most metals and,
more often than not, destroy whatever they are in.  NiCads and Alkalines
may leak a little if left dead for a long time but the residue can be
washed off with water and is not very corrosive.  Sometimes this residue
will also form and insulating barrier on a battery contack, making the
user think the device is broken.  This stuff can be chipped away though.

This response has been erased.

there is a fairly new techniqe for recharging nicads in which the battery
does not have to be fuly depleted first. however, that said (and paid
for with a pricy recharger) ... nicads have a 'memory' about how much
they are 'required to work.'
  
if nicads are discharged/worked only, oh, say, 1/4 of their potential
and then recharged... they 'remember' that they were only re2quired to
work 1/4 of their capacity ... therefore that's all they will work in
the future.
  
i don't remember if the memory is immediate or if it takes a few cyclings
at some lesser usage to develop the memory... but nicads learn how to
cop out of working up to full potential.
  
i just shake my head at ppl who put their wireless phone right-back-in-the-
base-unit after a phone call (as one example). i have used phone nicads
for periods of almost 3 years before they finally die. after a full charge
when newly acquired .... don't put the phone in the base unit until and
unless the damn thing dies totally. 
  
same with those power tool batteries (which now are
interchangable/replaceable).

drain them completely before recharging.
  

*Never* drain a NiCad completely. They should be drained down to about 1.0
volts per cell (they start at ca. 1.2 volts), and then recharged. There
are two problems with draining NiCad packs completely. One is that the
chemistry doesn't like it. The other is that not all cells are identical,
so the weakest cell in the pack is drained completely and then run in
reverse, before the other cells are depleted. Running a NiCad in reverse
usually destroys it. 

A NiCad drops from a nominal original voltage of 1.2 volts to 1.0 volts
when about 90+% of its capacity is exhausted. 

I have a utility on my laptop that drains the battery to that low volage
cutoff, and then turns it off. This usually rejuvenates the battery from
the so-called "memory effect". 

I do what TS does with all NiCad powered devices: run them until they are
weak (not dead), and then recharge them. I never leave them on "charge"
when not in use, except after a discharge treatment (and then only until
recharged). 

I keep hearing that the NiCad "memory effect" is practically an urban legend,
since the design flaw that causes it was fixed years ago.  I've also read that
a similar effect can be created by constant charging.  My NiCads are mostly
used in the "ideal" situation, a (nearly) full charge/discharge cycle every
time.

Call it what you will, but if a NiCad is not fully cycled, you will
experiance reduced power output.
 
The Motorola portable phone I got late last year came with Metal Hydride
(sp?) batteries.  These are suppose to have a higher energy density (More
power for the package size) and not have the "memory", etc. anomaly of
NiCads.

True.  My dad has those on his laptop.  Much smaller battery, no memory so
far after 6 months or so of use.

somehow I think it speaks volumes that an item on batteries here gets five
times the reponses that an item (previos item) on romantic love does.  It
shows where the midns of grexers are :)

Depends on what you get a charge out of.

(I don't respond in your items, Richard.  It's my quiet way
 of protesting your bizzare behavior.  Others might be doing
 the same - hard to tell.)

So, if I get one of these NiCad rechargers am I going to 
have to pay close attention to the batteries, checking them
to see so that they don't go too dead?  I don't want to 
get into having to nurture batteries.  I just want my few
battery needs to be met without a lot of fuss.  I gotta
tell ya, this sounds like "fuss" to me.  But I appreciate
the information.

Nah, just use the NiCads until they run out, then recharge them overnight.
Your battery-using devices will stop working at just about the right point.

if i get a metal hydride battery, will i fall in romantic love?

  What scott said.  I've had mine 7 years, and I don't even think of them.
When they don't carry my voice, time for the charger.

(Shucks, rcurl changed his name!)

This response has been erased.

(Different item)

I have linked agora 76 (Batteries) to hardware 126. There is also
hardware 84 (BATTERIES). BATTERIES is a bit more technical than Batteries,
but take your pick. Maybe, BIG batteries and little batteries?

Mary, ic you haven't forgotten this item yet, I *have* used NiCad 9v batteries
(currently on my second) for several yeals now.  The only annoyance is that
NiCads tend to run out of juice rather abruptly.  Carry a spare to
perfrmances. (an alkaline works great as a spare, and will last for years in
that role).

(still using most of my brain on the Dvorak keyboard)

I meant to say that I have used NiCads in my own tiner, and they wort just
fine.  

With my current roster of rechargeable batteries, I feel verf put out when
I actually have to *biy* a new battery.  :)

Tuner, not "tiner".  Damn this netlag!!!

(Scott unsheathes his tanto and commits seppuku)

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