Keyboard burning through batteries

[Paul]

Hi Buffalo,

I have a Bachelor of Science in Electrical Engineering,
Cum Laude. Not bragging; just letting you know my creds.

David's observation is a good one. The Voltage does not
"Sag" as fast with the Lithium and would wear out the
filament faster.

Love LED flashlights. Have a 3 AA cell, all plastic one
from C-Crane that I use inside computer cases, etc., as
I am not worried about metal parts shorting anything out.

-T

To a first order approximation, you ask what the values
of battery voltage are. As a starting point. So I think
as an end-user, Buffalo is asking the right question.

If you connect a 3V bulb to a 6V battery, it doesn't
matter what the (commercial) battery is made from - you
know the results will not work out well. Many home experimenters
learn this, by ruining one of the flashlight bulbs in their
collection, by performing such a test.

This is how I got started in electronics. Testing batteries
and flashlight bulbs at an early age.

*******

If a person wanted info on how some of the properties of batteries
are measured, this site is good.

http://batteryuniversity.com/learn/article/how_to_measure_internal_resistance

http://batteryuniversity.com/index.php/learn/article/testing_lithium_based_batteries

The information is only useful, if you know what to do with it.

*******

If you know the basic circuit characteristics well enough
(or, if the flashlight filament will last long enough for
you to make some simple measurements), you can adjust the
circuit to work with a slightly different battery type.

R_adj

Vbat ---Rbat ----X X--------+
(approx) |
Filament (R varies with temp)
|
Return -----------------------+

You can use a variable resistor. As a kid, I had a small screwdriver
adjustable wirewound potentiometer, to use as R_adj, and that
worked fine for setting the flashlight bulb operating point.
I could trade off the amount of light, versus filament lifetime.
A flashlight bulb might be intended for 100 to 200 hour lifetime
(i.e. less than incandescent bulbs in your home).

You can also use Schottky diodes for adding drop to a circuit.
I used back to back pairs of Schottky diodes on my bicycle
bottle dynamo and incandescent bulbs, to adjust (balance)
current flow as desired between front and back lights.
(The dynamo [generator] is A.C., which is why diodes are used in pairs.]
With two six volt bulbs, one in back, one in front,
three pairs of these in series, made the back light a
bit dimmer, and allowed more current flow to the front.

|\ |
---+---| \|---+--- Back to back diodes,
| |/ | | drop 0.7V in an AC circuit
| | The exact drop, varies with current.
| | /| |
+---|/ |---+
|\ |
| \|

The diode obviously has different dynamics than a resistor,
and is for usage under known and relatively well controlled conditions.
The wirewound adjustable resistor, they're just not as available,
and a lot of them too cumbersome. And that's where a collection
of miniature diodes comes in handy. Most of the other wirewound
stuff I acquired over the years, was huge by comparison.

(diode types can drop 0.7 to 1.0,
Diode Diode depending on type and current.
|\ | |\ | Schottky 0.3V drop, but at low currents)
Vbat ---Rbat ----| \|--| \|--------+
(approx) |/ | |/ | |
Filament (R varies with temp)
|
Return ----------------------------+

At typical current flow levels, a diode may offer too much drop
in this application. But the diode idea is still useful for
lots of other things. I use it to set the fan speed in my computer.
I have a 12V fan, with seven diodes in series with it, to get
the voltage level needed to run the fan slower. So the diode idea
is still an alternative to clunky variable wirewound resistors.
The diodes still get warm, and you have to work out
the thermal dissipation to know if what you're doing
is safe.

You can use resistance wire of your own concoction, like Nichrome.
Which can be obtained from old toasters. If you can't solder to
it, you can try steel rivets as a compression solution. Squash
the nichrome against your connecting wire. Wikipedia has some
info on Nichrome resistance.

Lots of flashlights, afford no space or place to make adjustments.
The last flashlight I bought, is "solid" where it counts, and
there is absolutely no place in that flashlight to hack in anything.
But my older flashlights, I could add a solution to allow usage
of another battery type. If it was really necessary or desirable.

By the way, I have a Bachelor of Science in Being Practical (BSBP).

Paul

 

[Buffalo]

"Todd" wrote in message news:[email protected]...

Hi WV,

It might be your batteries. Where did you buy them
from?

Had a similar problem with a wireless mouse. I was buying
alkaline batteries from Wal Mart. Figured I was safe
buying brand name batteries. They lasted about a week.
And their "Use By" dates were several years out.

I worked for a company that did business with Wal Mart.
They screw their vendors. So, Walt Mart gets a lot
of back door and almost rejects because of their
attitude to their suppliers.

C'mon now. You are trying to tell this group that the Energizer batteries
that Walmart sells (with the same exp date) are of a poorer quality than
those same batteries (Energizer) that are sold by 'your' store?
Can't and won't buy that advice. Sounds like a personal vendetta to me.
Logic dictates that your premises are lacking , therefore your conclusion is
without basis or merit.
Actually a larger store usually has 'fresher' batteries due to turnover.
Now, when it comes to Budweiser beer and their dates, that is another
story!!!
How's that?

I switch to Raley's for batteries. Alkaline (store
brand and name brand) lasts about 1-1/2 months.
Lithium lasts a little over 3 months.

If not your batteries, it may be time to get a new
keyboard.

-T

p.s. there are only three manufacturers of batteries
world wide, so buy the store brand -- they are
cheaper and all made by a brand name.

I disagree with your conclusions about buying batteries at WalMart since you
did not

 

[Todd]

Basically the only way a filament will be hotter is if there is an
increase in voltage.
Since Lithium batteries keep their peak voltage until just before they
quit, your point has 'some' merit.
It you keep the batteries fresh, than the only way the bulb filament
would burn out quicker is if the applied voltage was increased.
SO, what is the voltage of a li battery compared to an Alkaline bat of
the same published voltage rating?

Buffalo,

The voltage from a battery decreases under load (lithium can support
more load) and as their capacity decreases (lithium has more capacity).
This is what I meant by sag. The voltage is not the same through the
lifetime of the two batteries.

-T

 

[Todd]

To a first order approximation, you ask what the values
of battery voltage are. As a starting point. So I think
as an end-user, Buffalo is asking the right question.

If you connect a 3V bulb to a 6V battery, it doesn't
matter what the (commercial) battery is made from - you
know the results will not work out well. Many home experimenters
learn this, by ruining one of the flashlight bulbs in their
collection, by performing such a test.

Remember to test them under load.

This is how I got started in electronics. Testing batteries
and flashlight bulbs at an early age.

Mine was Christmas lights

 

[Todd]

If there are only three manufacturers, that's the first time I've
heard that. What are the names of the three manufacturers? Do you have
a web citation for that?

Can remember were I heard it. Think it was consumer reports.
It is only for the AA's etc in the store.

 

[Ken Blake, MVP]

Not to mention that "lithium" cells are
_far_ more expensive than alkalines; I'd only use them where the
capacity is really needed, such as polar expeditions and the like, or
the long shelf life is, such as an emergency torch (US: "flashlight")
(and probably not even there). I'm moving towards long-retention NiMH
cells for most things.

I know that many people disagree with me, but I wouldn't use any kind
of a battery on a keyboard. I have never seen any value to a wireless
keyboard.

And ditto for a wireless mouse. Except perhaps for use with a laptop
when traveling, I see no value to a wireless mouse either.

 

[J. P. Gilliver (John)]

Getting a long way from XP here (-:!


It _might_, but that's easily testable - try some rechargeables that are
known good (e. g. the ones you use in your camera, assuming you use
rechargeables in that).
[]I share Ken's doubt about that. I expect there are _far_ fewer companies
than there are trade names, but I doubt it's as low as three. Having
said that, if buying primary cells (i. e. non-rechargeables), I'd buy
store-brand alkalines. (For a _few_ really low-drain uses, I used to
even buy zinc-carbons, but they seem to have a poorer shelf life, i. e.
they rot even if not used more than "alkalines". IME, of course.)
And it's very difficult to obtain those figures, too. Last time I looked
- which was quite a few years ago - the only distribution source that
published mAh capacities for non-rechargeable (such as "alkaline")
cells, in the UK anyway, was the Farnell catalogue. (And you're right,
they don't vary much.)
They _may_ do that - but if so, it suggests the torches are designed for
a lower voltage than nominal (in which case I'd use rechargeables anyway
- the long-retention ones if that's important).
Only if their increased capacity is greater than their price premium, or
important in your application, or the shelf life is. (Personally I would
try to avoid anything that uses AAAs, especially if more than one, and
as for 9v - if you mean the little ones - those are about the most
expensive way there is to buy energy, whatever the technology!)
I remember when NiCds were in their heyday there was also the fact that
they had a lower internal resistance, which upset some types of load
(which would include a filament bulb, as these are a virtual short at
switch-on). [I think NiCds still do have the lowest internal resistance
of any of the common chemistries, which means they do hang on in a small
number of applications.] Lithiums may also have quite a low Rint.

Hi Buffalo,

I have a Bachelor of Science in Electrical Engineering,
Cum Laude. Not bragging; just letting you know my creds.

David's observation is a good one. The Voltage does not
"Sag" as fast with the Lithium and would wear out the
filament faster.

Only if the filament torch is designed to run from a lower than initial
voltage. (Which it may well be.)

Love LED flashlights. Have a 3 AA cell, all plastic one
from C-Crane that I use inside computer cases, etc., as
I am not worried about metal parts shorting anything out.

-T

Yes, I don't see any reason to buy a filament one these days.

 

[Ken Blake, MVP]

Can remember were I heard it. Think it was consumer reports.
It is only for the AA's etc in the store.

I just did a web search, and from what I can see, what you say is
*not* correct; there are apparently *many* manufacturers. I didn't
look for AAs in particular, though.

 

[J. P. Gilliver (John)]

In message <[email protected]>, David H.

Read Consumer Reports. They did a comparison showing the cost per
picture is lower on Lithium than Alkaline batteries.

http://www.consumerreports.org/cro/magazine-archive/2011/december/electr
onics-computers/batteries/overview/index.htm

"Lithium batteries took more photos than the other types, so they don't
need to be changed as often. The best performer, Energizer Ultimate,
costs $6.00 per pair but just 23 cents per 50 shots. The top alkaline
battery, Duracell Ultra Advanced, costs $3.65 per pair but ends up
costing 70 cents per 50 shots."

(December 2011.) But, although they did recommend using rechargeables
for some things, they didn't actually say how many "shots" they got out
of them. For common cell sizes such as AA and AAA, I wouldn't consider
using primary cells in _any_ high-drain application, and probably not
others either, except for the few cases where the time taken to change
them matters (at a pinch, some areas of professional photography, I
suppose, though such professionals often carry two or more cameras
anyway in case anything else fails). I'd pay the slight extra for
long-retention NiMHs.
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Another lively meeting of thr 1922 Committee - the secret gathering of BBC
presenters that gets its name from the fact that no one is sober after
twenty-past seven. - Eddie Mair, RT 16-22 April 2011

 

[Buffalo]

"Todd" wrote in message news:[email protected]...

Buffalo,

The voltage from a battery decreases under load (lithium can support
more load) and as their capacity decreases (lithium has more capacity).
This is what I meant by sag. The voltage is not the same through the
lifetime of the two batteries.

-T

Alkalines have a better voltage maintaining level than the old carbon ones,
as you well should know.
Actually the load is not as important as the total wattage used and the time
involved. Load by itself (for a flashlight) should not cause a lower voltage
with a fresh battery.
When alkalines near the end of their useful life, the voltages decreases
earlier than that of a lI battery.

My first point was that the only thing that would shorten the filament life
would be higher voltage.

I don't know how you could possibly disagree with the above line.

 

[J. P. Gilliver (John)]

In message <[email protected]>, "Ken Blake,

I just did a web search, and from what I can see, what you say is
*not* correct; there are apparently *many* manufacturers. I didn't
look for AAs in particular, though.

Many brand names. Probably far fewer actual manufacturers - though I
suspect significantly more than three. I'm pretty sure Varta in Germany,
at least one in Japan (Sanyo?), and at least one (Union Carbide?) in
USA; I'm not sure if there's a UK one. (There certainly used to be, Ever
Ready; I think they became part of Berec, and I'm not sure where that's
based or if it still exists.) I'd also be extremely surprised if there
isn't at least one in China.
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Another lively meeting of thr 1922 Committee - the secret gathering of BBC
presenters that gets its name from the fact that no one is sober after
twenty-past seven. - Eddie Mair, RT 16-22 April 2011

 

[J. P. Gilliver (John)]

NiMH has its own problems such as the "memory Effect".

I'm not sure it's been proven for NiMH (even for NiCd it's not as
clear-cut as once thought). The new long-retention (80-90% charge
remaining even after a year; _slightly_ lower capacity, e. g. 2½ rather
than 2.9 Ah for an AA) ones have less if any. But even if they do have
such problems, to me they're still cheaper to run than "alkalines" - and
certainly than "lithiums".
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Another lively meeting of thr 1922 Committee - the secret gathering of BBC
presenters that gets its name from the fact that no one is sober after
twenty-past seven. - Eddie Mair, RT 16-22 April 2011

 

[Buffalo]

"David H. Lipman" wrote in message

On the ground that Lithium is a constant power source up to and around the
knee.

Alkaline power decays over time.

based upon the technology, each battery of the same format will have
different specs. One is the voltage.

I believe Alkaline are AA and AAA are 1.5v ~ 1.65 and Lithium is 1.65 ~
1.85v.

I just did a simple no-load DMM test with two AAA and I got 1.518v for
Kingwolf Alkaline and 1.823v for Energizer Ultimate Litihum.

Combine the slighly higher voltage against a constant load of the filament
and the consistent power level of Lithium, the end result is a shorter
filament life. Additionaly since the voltage is slightly higher, the
filament burns hotter so the resilience of the filament to g-force under
power is lowered. Thus using Lithium batteries with a filament bulb will
mean reduced life and a greater propensity of premature filament failure.

Due to the higher voltage and that is what I said. Not load or anything
else, only a higher voltage.
Overall, the life of the filament is determined by the voltage across it and
time. (not counting vibrations)

 

[J. P. Gilliver (John)]

In message <[email protected]>, David H.

If this was a electronics news group then we can take it to the nth
degree and get into those factors. The memory effect is more appros to
a unit that is partially discharged and then recharged vs. fully
discharged and recharged. One reason why they are not used in
notebooks (and the weight).

Since it is an OS news group and where just touching the concept of a
powered peripheral, I think we can leave it at NiMH has its abilities
and disabilities to Lithium Ion. However they both outperform alkaline
which is the most common COTS battery technology.

(Actually, in terms of units sold, I think the old zinc-carbon may be
holding its own, since poundshops and the like seem to be selling them
in packs of twenty or similar!)

I thought you were talking, when it comes to AA cells and the like, of
primary - non-rechargeable - "lithium" cells. Not the same (though I'm
not familiar with the chemistries and structures involved) as the
rechargeable lithiums now being used in everything from laptops to
fobile moans to mini camcorders to ...
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Another lively meeting of thr 1922 Committee - the secret gathering of BBC
presenters that gets its name from the fact that no one is sober after
twenty-past seven. - Eddie Mair, RT 16-22 April 2011

 

[Buffalo]

"David H. Lipman" wrote in message

Yes but it is not just the fact that Lithium provides a slightly higher
voltage, it is that the load will see less power from the source as a
function of time with Alkaline vs. Lithium technology. That's the power
decay I mentioned. Its why before you declare you have "dead batteries"
the white light of a flashlight bulb gets duller until orange and then no
light. From the bulbd POV thats good because it prolongs the filaments
life.

"not counting vibrations" equates to "the resilience of the filament to
g-force under power"

'G-force under power', I like that term.
The higher the voltage , the hotter the filament and the shorter the
filament life. We agree.

 

[J. P. Gilliver (John)]

From: "J. P. Gilliver (John)" <[email protected]> []

I thought you were talking, when it comes to AA cells and the like,
of primary - non-rechargeable - "lithium" cells. Not the same (though
I'm not familiar with the chemistries and structures involved) as the
rechargeable lithiums now being used in everything from laptops to
fobile moans to mini camcorders to ...

In devices like that you don't see cycles of 100% charge to 100%
discharge. You see 100% charge then a partial discharge and then 100%
recharge. Over time the cycles of non-fully discharging causes the
NiMH to have a greater memory effect. That is after x cycles the NiMH
won't go to 100% charge anymore and it is now at something lower. These
also are mobile devices. Therefore between the memory effect and the
greater weight og NiMH, NiMH is not "optimum" for these devices and why
the manufacturers default to Lithium technology.

I know what the (alleged) memory effect is about. (NiMHs have it less
than NiCds - in fact I'm not convinced they do have it, though they can
appear to.)(Remember, this started with a wireless keyboard, which I suspect just
takes AA cells!)

In all respects but one and a half, lithium rechargeables are superior
to most of the other common types: better energy density, lower weight.
The one respect in which they are "inferior" is that they need much more
careful charging - in particular, where there are cells in series.
(That's why nearly all small devices use single cells; the fact that a
lithium rechargeable has a voltage of (IIRR) about 3.7 means that for a
lot of cases, a single cell (of various capacities) is what's used.

In older equipment designed to have two, three, or four (or more) cells
in series to give a higher voltage, there is a danger that on discharge
some could be reverse charged, which is a positive feedback case (i. e.
once it's started to happen, it can only get worse).

In these cases, the cells should ideally be charged separately. NiMH
need less sophisticated charging circuits than Li (though more than
NiCds).

Li _non_-rechargeables shouldn't be charged; they're a different
technology to the rechargeable ones. They have a voltage nearer the 1.5
of ZnC (you've measured some of them as around 1.8, and I see no reason
to disbelieve that) than the ~3.7 of rechargeable Lithiums.

I've forgotten what we were actually arguing about here (-:! So I'll
summarise my position:

For equipment *designed to take 1.x volt cells*, possibly several of
them, you can use either primary cells or rechargeables. Primary can be
either the original zinc-carbon (low capacity but cheap; sometimes
cost-effective for low-drain applications, though the cost drives tend
to make them poorly made), "alkaline" (of which there are many brands,
but their capacities are not that different), or "lithium" (the most
expensive; possibly cheapest in terms of capacity in high-drain
applications, though this isn't entirely proven). Rechargeables can be
nickel-cadmium (low capacity - < 1Ah in AA size - by today's standards,
environmentally unfashionable so no longer available in many countries,
and most likely to be prone to the memory effect if it exists. Capable
of high discharge currents though), ordinary nickel metal hydride (up to
about 3 Ah in AA size; cheapest to run for high-drain frequent-use
applications; _may_ suffer from memory effect, tendency to
self-discharge over a few weeks or months), or long-retention nickel
metal hydride (up to about 2½ Ah in AA; similar to ordinary NiMH except
that they retain 80-90% charge even after a year [and are often sold
charged]).

For equipment designed for them, single-cell (though various sizes and
thus capacities of cell) rechargeable lithium are a good bet. Most
mobile 'phones, and many modern camcorders and the like use these.

For reasons I am not sure of, laptops and the like tend to be designed
to use higher voltages, thus use multi-cell rechargeables, with complex
charging circuitry (often built into the battery pack itself) to make
sure none of the cells are reverse or over-charged.
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

.... unlike other legal systems the common law is permissive. We can do what we
like, unless it is specifically prohibited by law. We are not as rule-bound
and codified as other legal systems. - Helena Kennedy QC (Radio Times 14-20
July 2012).

 

[J. P. Gilliver (John)]

In message <[email protected]>, David H.

There are two states the bulb will be under. With power (voltage
applied) and without power (no voltage applied) and the amount of
g-force the filament can handle will be different under those two
states. We are talking about voltage applied and thus 'G-force under
power' state. The resilience of the filament to resist breakage will
decrease as the power applied to the filament increases.

There's a third state, which is a special form of the powered state:
power applied but still cold. A cold filament has a very low resistance
until it warms up - thus a very large current flows at the moment of
switch-on. (That's why your lights flicker when you turn on a kettle!)
This "inrush current" is affected by various factors: the actual initial
voltage of the cell (so its very first part may be higher for lithiums
if their voltage is higher), and the internal _resistance_ of the cell
(low for NiCds [and lead-acid], so the overall surge is high for them).
A high inrush current can also shorten the life of a filament, as it
shocks it, causing mechanical stresses - for a coiled filament, it can
generate magnetic mechanical forces. (And for the very first -
high-frequency - part of the surge, almost any filament is at least one
half turn of a coil.)
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

.... unlike other legal systems the common law is permissive. We can do what we
like, unless it is specifically prohibited by law. We are not as rule-bound
and codified as other legal systems. - Helena Kennedy QC (Radio Times 14-20
July 2012).

 

[Todd]

I just did a web search, and from what I can see, what you say is
*not* correct; there are apparently *many* manufacturers. I didn't
look for AAs in particular, though.

Hi Ken,

I could be wrong. Wouldn't be the first time.

On doing some research myself (instead of just
relying on memory), it turns out that it is America
that only has three manufacturers. If the generics (AA,
AAA,C, etc.) say "Made in USA", then they are
Duracell, Energizer, or Rayovac. I did not find a lot
of good references though. So, I could still be wrong.

My compliments on how you told me I was wrong. You
are a true gentleman. Very well done. I look forward
to your letters in the future.

Some of the folks on these groups are really ill mannered.
"WRONG!" and they think folks would even listen to them.
Either they don't realize that no one would want to listen
to them or they just like to condescend and pick fights.
I can see them driving their cars around with their arm
out the windows and their middle fingers extended. I
do my best to ignore them, although I have responded too
many times in the past.

-T

 

[Todd]

I know that many people disagree with me, but I wouldn't use any kind
of a battery on a keyboard. I have never seen any value to a wireless
keyboard.

And ditto for a wireless mouse. Except perhaps for use with a laptop
when traveling, I see no value to a wireless mouse either.

Hi Ken,

1+

I hate when batteries start going dead on keyboards and mice.
It is always at the worst time. If I have to use wireless, I
use Lithium, like Ken.

Better yet, I use wired. Love my Unicomp keyboard. Like
an IBM Selectric.

-T

 

[Ken Blake, MVP]

Hi Ken,

I could be wrong. Wouldn't be the first time.

On doing some research myself (instead of just
relying on memory), it turns out that it is America
that only has three manufacturers. If the generics (AA,
AAA,C, etc.) say "Made in USA", then they are
Duracell, Energizer, or Rayovac. I did not find a lot
of good references though. So, I could still be wrong.

My compliments on how you told me I was wrong. You
are a true gentleman. Very well done. I look forward
to your letters in the future.

Well, it's a subject that I know little about and I didn't know you
were wrong. I just thought you were wrong.