The problem with making comparisons is that the power you can get out of
most types of primary (non-rechargeable) cells depends heavily on a lot
of factors, such as:

-- Current drain
-- Duty cycle
-- Temperature
-- End voltage

In addition, some devices such as many GPS receivers have switching
regulators, which drain the battery at a near constant power rate.
Others drain at a nearly constant current rate, and still others with
more like a resistive load. Each type of cell behaves differently under
each condition.

Only a few rules of thumb can be put forth:

1. For heavy drain applications such as photoflash or an HT, alkalines
last many times longer than "heavy duty" carbon-zinc types, so the
latter is seldom an economical choice for those applications. Likewise
for applications with moderate but constant drain such as a GPS
receiver. Carbon-zinc is probably more economical (unless you use
alkalines from Costco or other discount store) for light-drain,
intermittent use such as a radio. Flashlights aren't light drain, but do
fairly well with carbon-zinc if used only occasionally. But I don't use
carbon-zinc for anything.

2. You're unlikely to see cell life increase anywhere near in proportion
to cost by using "titanium" or other "premium" alkaline cells -- their
special characteristics are mostly created in the marketing department.
If in doubt, consult the manufacturer's data sheet, readily available on
the web.

3. Modern NiMH cells have about the same capacity as alkaline cells --
more at very high currents --, and the capacity is quite constant over a
wide range of discharge conditions. A down side is the high
self-discharge rate -- they're not a good choice for something like a
flashlight that's used only occasionally.

4. I've never found a good use for the rechargeable alkalines. Their
capacity drops with each recharge and with increased current. At higher
currents, the capacity decrease is even faster. NiMH or primary alkaline
has been a better choice every time I've done a careful comparison.

5. The 1.5 volt primary lithium cells have more capacity than either
alkaline or NiMH, especially better than alkaline at high currents.
They're very light weight, have a long shelf life, and are excellent at
low temperatures. But they cost like the dickens. I keep a couple of
them in my emergency kit when backpacking or cross-country skiing as a
backup for GPS or flashlight, but don't use them regularly.

I've tested a good number of various alkaline AA cells at constant
current loads of around 200 mA, and found only minor and inconsistent
capacity differences among brands and types. Consequently, I usually use
the ones I buy at Costco for about 25 cents each.

If you have a particular application in mind, check the data sheet for
the performance under the conditions you anticipate. Then you pays your
money and makes your choice.

Roy Lewallen, W7EL

wrote:
Has anyone investigated the quality/life/efficiency/MostBangForTheBuck/
whatever of ordinary AA (or other) cells? I recently saw the following
in a local sto

(I determined COST as the price for the most-economical
blister-pack divided by the number of cells in that pack.)

$ COST
EACH MANUFACTURER BRAND NAME OTHER CLAIM
------ ------------ ---------- ------------------------------
0.4435 Duracell CopperTop
0.4435 Energizer Max
0.81 Energizer Titanium
0.2875 Rayovac Alkaline Same Performance, Better Price
0.235 Rayovac Heavy Duty
0.36 (StoreBrand) Ever Alive

2.105 Energizer Lithium
2.4575 Energizer Rechargable
2.2425 Rayovac Rechargable

"Roy Lewallen" bravely wrote to "All" (03 Nov 05 16:08:56)
--- on the heady topic of " Battery
quality/life/efficiency/MostBangForTheBuck/whatever"

RL From: Roy Lewallen
RL Antenna Software Xref: core-easynews rec.radio.amateur.homebrew:88706


RL The problem with making comparisons is that the power you can get out
RL of most types of primary (non-rechargeable) cells depends heavily on a
RL lot of factors, such as:

RL -- Current drain
RL -- Duty cycle
RL -- Temperature
RL -- End voltage

There is another factor I've discovered for a cell's usage in audio
applications such as a battery powered portable mixer or especially an
electret microphone. Alkaline cells seem to be plagued with pops and
ticks while carbon cells are dead quiet in comparison. Since most
electret mics have very simple electronics with no voltage regulation,
the battery must be extremely quiet. Unfortunately I don't have the
numbers on hand to document my experience but this is just to comment
that sometimes there are other factors (noise) which may make a cell
type more desirable for very specific applications. For example
electric guitar players are sticklers for the type of square 9 volt
batteries that go into their vintage pedals.

A*s*i*m*o*v

.... May you find the light and walk the mountain tops.

In article ,
Roy Lewallen wrote:

| Only a few rules of thumb can be put forth:
|
| 1. For heavy drain applications such as photoflash or an HT, alkalines
| last many times longer than "heavy duty" carbon-zinc types, so the
| latter is seldom an economical choice for those applications. Likewise
| for applications with moderate but constant drain such as a GPS
| receiver. Carbon-zinc is probably more economical (unless you use
| alkalines from Costco or other discount store)

.... well, if you're looking for the most bang-for-your-buck, you
SHOULD be getting the non name brand alkalines

Personally, I've not found carbon-zinc batteries to be more
economical, unless you're not actually using them.

| But I don't use carbon-zinc for anything.

Me neither.

| 3. Modern NiMH cells have about the same capacity as alkaline cells

In my experience, the alkaline cells have higher capacities, about
twice as high.

| more at very high currents -- and the capacity is quite constant
| over a wide range of discharge conditions.

And this is very true. The alkalines suffer greatly if you discharge
at a high rate, where the NiMH cells do just fine.

| A down side is the high self-discharge rate -- they're not a good
| choice for something like a flashlight that's used only
| occasionally.

Yup. NiCd cells are better, but still nowhere near as good as
alkaline or lithium cells with regard to self discharge rates.

--
Doug McLaren,
`Ever heard of .cshrc? That's a city in Bosnia. Right?' -- Discussion in
comp.os.linux.misc on the intuitiveness of commands