Alkaline and rechargeable batteries and devices

[Phil Allison]

"Michael Black"

Devices that use batteries are generally expecting 1.5volts, though in
this day of rechargeables that may need to be revisited.

** Not true at all.

Alkaline cells are only * nominally * 1.5 volts - real examples test
around 1.6 volts when unused FALLING almost linearly to below 1.0 volts
when exhausted.

Any equipment maker who relies on a voltage of 1.5 volts ( or even 1.3
volts ) from each alkaline cell for his design to work is a criminal ASS !!

Very few devices are so *badly designed* that they will not work perfectly
OK with cells supplying 1.2 volts each.

Rechargeables do have less of a "life". If the unit needs a minimum
voltage, the rechargeables will decay to that voltage before the 1.5v
batteries, since they start out at a lower voltage.

** Complete nonsense.

NiCd and NiMH cells have a very " flat " voltage discharge curve - the
voltage stays close to the nominal 1.2 volt value until the cell is
virtually exhausted. Alkaline cell voltage just keeps steadily falling in
use until they reach exhaustion at about 0.8 volts.

Rechargeable NiMH cells * long outlast * alkalines in devices like digital
cameras.

Some equipment
may even watch the voltage and turn itself off if the voltage goes
below a certain point, again working against rechargeables.

** Only junk designed by total idiots would switch off at more than 1.2
volts per cell.

Apparently some crappy MP3 players qualify.

Some devices need the 1.5v to start out, and rechargeables aren't the
way to go.

** Bollocks.

Such a ridiculous device would only ever use about 10% of the capacity of an
alkaline cell.

Likewise, some devices that have such a slow current draw
are better off with alkalines, since they keep their voltage longer
than a rechargeable.

** Yeah - in things like wall clocks and rarely used torches.




........ Phil

 

[David L. Jones]

On Nov 8, 3:07 am, kimiraikkonen <kimiraikkone...@gmail.com> wrote:

Hi,
I heard something but i want to make sure that i experienced that:

If i use non-alkaline rechargeable batteries (i have GP ones, 1.2V
NiMH) on a mp3 player, after sometime although battery level is shown
%50 full, the mp3 player is turned off unexpectedly by itself.

So, isn't healty to use rechargeable batteries on mp3 players or
digital cameras?

It is just fine, *if* the product is designed to support them.
Virtually all digital cameras support NiMH.
Lots of MP3 players only support Alkaline cells.

If i use non-rechargeable standard AAA alkaline batteries (for once
use), the battery level info is much more reliable and mp3 player's
operation life is longer.

That is because the MP3 players voltage detection circuitry has been
obviously designed for Alkaline cells only.
Alkaline and NiMH cells have very different discharge characteristic
cells. So it's not always practical to have the one circuit to detect
both. For example, an Alkine cell will have expended all of it's
energy when it drops to 0.8V or so. A NiMH cell will have discharged
all it's energy when it drops to 1V. The circuitry in the device must
be designed to detect this and extract the maxmimum energy from a
chosen battery technology.
Products that support both will usually have a software detectable
threshold level that you can select in a menu somewhere.

Dave.

 

[Rich Grise]

On Wed, 07 Nov 2007 16:07:30 +0000, kimiraikkonen wrote:

I heard something but i want to make sure that i experienced that:

If i use non-alkaline rechargeable batteries (i have GP ones, 1.2V NiMH)
on a mp3 player, after sometime although battery level is shown %50
full, the mp3 player is turned off unexpectedly by itself.

So, isn't healty to use rechargeable batteries on mp3 players or digital
cameras?

If i use non-rechargeable standard AAA alkaline batteries (for once
use), the battery level info is much more reliable and mp3 player's
operation life is longer.

I knew that but i want to see a clear explanation why it is.

Because NiMHs are crap.

Cheers!
Rich

 

[Michael Black]

kimiraikkonen (kimiraikkonen85@gmail.com) writes:

On Nov 7, 6:33 pm, BobG <bobgard...@aol.com> wrote:
On Nov 7, 11:07 am, kimiraikkonen <kimiraikkone...@gmail.com> wrote:> I knew that but i want to see a clear explanation why it is.

=================================
If the computer is looking for 1.3 volts and it sees 1.2, it thinks
the voltage is too low and the batteries need charging?

Hi,
I'm talking about mp3 player or digital cameras. Another issue i don't
know why rechargeable batteries has labeled 1.2volts?
But that's not the answer of my question stated in first message.

The voltage is determined by chemistry. There's a reason carbon zinc

and alkaline batteries are 1.5v when fresh, and it's not because someone
decided to make them that way. That's what basic "cell" puts out. If
you need higher voltage, you cascade them. Take apart a regular 9v
battery, and you will see that it's made up of multiple cells, each producing
1.5v and when added together put out the necessary 9v. Same with any
higher voltage battery. The chemistry determines the voltage, and the
only way to get a higher voltage is to put more then one cell in
series.

Likewise rechargeables have a voltage defined by their chemsitry, which
good or bad ends up being slightly less than carbone zinc and alkaline
batteries. The only way you could boost the voltage is by putting
more "cells" inside the package, which gets problematic since there
isn't room to put more than one "cell" in an AA or AAA package and still
keep current capacity the same. And if you boosted the voltage, it
would be in 1.2v increments, not the needed .3v increment. Take a close
look at rechargeable 9v batteries, and many or most of them are actually
rated at 7.2 volts, ie six times 1.2v. Some squeeze in another "cell"
to get closer to 9v, but they are an exception.

Devices that use batteries are generally expecting 1.5volts, though in
this day of rechargeables that may need to be revisited. So any voltage
reading is based on the voltage starting at 1.5v (or some multiple if
there are more than one battery in there) and dropping down. The
rechargeables start out at 1.2v, which gives an illusion of weaker
batteries to start with.

Rechargeables do have less of a "life". If the unit needs a minimum
voltage, the rechargeables will decay to that voltage before the 1.5v
batteries, since they start out at a lower voltage. Some equipment
may even watch the voltage and turn itself off if the voltage goes
below a certain point, again working against rechargeables.

Some devices need the 1.5v to start out, and rechargeables aren't the
way to go. Likewise, some devices that have such a slow current draw
are better off with alkalines, since they keep their voltage longer
than a rechargeable.

Michael

 

[kimiraikkonen]

On Nov 7, 6:33 pm, BobG <bobgard...@aol.com> wrote:

On Nov 7, 11:07 am, kimiraikkonen <kimiraikkone...@gmail.com> wrote:> I knew that but i want to see a clear explanation why it is.

=================================
If the computer is looking for 1.3 volts and it sees 1.2, it thinks
the voltage is too low and the batteries need charging?

Hi,
I'm talking about mp3 player or digital cameras. Another issue i don't
know why rechargeable batteries has labeled 1.2volts?
But that's not the answer of my question stated in first message.

 

[BobG]

On Nov 7, 11:07 am, kimiraikkonen <kimiraikkone...@gmail.com> wrote:

I knew that but i want to see a clear explanation why it is.
=================================

If the computer is looking for 1.3 volts and it sees 1.2, it thinks
the voltage is too low and the batteries need charging?

 

[kimiraikkonen]

Hi,
I heard something but i want to make sure that i experienced that:

If i use non-alkaline rechargeable batteries (i have GP ones, 1.2V
NiMH) on a mp3 player, after sometime although battery level is shown
%50 full, the mp3 player is turned off unexpectedly by itself.

So, isn't healty to use rechargeable batteries on mp3 players or
digital cameras?

If i use non-rechargeable standard AAA alkaline batteries (for once
use), the battery level info is much more reliable and mp3 player's
operation life is longer.

I knew that but i want to see a clear explanation why it is.

Thanks...