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MagLite, Krypton bulbs and NiCd batteries
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John Savage
science forum addict


Joined: 24 Mar 2005
Posts: 63

PostPosted: Sat Jul 01, 2006 5:38 am    Post subject: Re: MagLite, Krypton bulbs and NiCd batteries Reply with quote

TwistyCreek <anon@comments.header> writes:
Quote:
I have a Mini MagLite that takes 2 AA alkaline cells.
It uses a small krypton bulb. The instructions say
to avoid rechargeable batteries (NiCds; I don't
remember what it said about rechargeable alkalines,
NiMH or Li-ion rechargeables.)

I wanted to test some new NiCds to see how long they'd
last and started a flashlight test. It didn't take too
long for the bulb to dim and eventually turn black
and stop working.

Why can't you use NiCds with the MagLite krypton bulbs?

I'm theorising here. You mention NiCds--this suggests to me that the
flashlight was manufactured some years ago because NiCds have been
left behind by NiMH technology in the last 3 or 4 years. I'd say
that the manufacturers recommended you avoid NiCds because you'd be
disappointed with their performance in your flashlight and probably
WRONGLY blame the flashlight. Besides having a lower voltage, the
capacity of NiCd cells was perhaps 66% lower than that of alkalines a
few years ago so the NiCds would go flat in comparatively short time
up against the higher AhC of alkalines. Even today, the top alkalines
are still just ahead of available NiMH rechargeables in capacity.

I can't see any other problem. I've used NiCds in the past and now
NiMH AA cells in my maglite and the life of the bulb is phenomenonally
long, at least a couple of years. I can't be certain now that it's
krypton, but I think it is; it's defintely not a xenon bulb.

Cross-post added for wider opinion on the care and feeding of a krypton
bulb.
--
John Savage (my news address is not valid for email)
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Mark Thorson
science forum Guru Wannabe


Joined: 04 May 2005
Posts: 102

PostPosted: Tue Jun 27, 2006 7:28 pm    Post subject: Re: MagLite, Krypton bulbs and NiCd batteries Reply with quote

TwistyCreek wrote:
Quote:

Why can't you use NiCds with the MagLite krypton bulbs?

(I can't find the answer on the MagLite web pages, some
of which say "Coming Soon". Not all MagLites use the
krypton bulb: some use xenon, halogen or 'hi-intensity
bi-pin' bulbs.)

NiCd batteries have a very low internal resistance.
Incandescent light bulbs present a dead-short load
at start-up, not developing high resistance until
they get hot. Maybe the NiCd batteries are ramping
up the power too quickly for a halogen bulb?
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Ron Jones
science forum Guru Wannabe


Joined: 16 May 2005
Posts: 175

PostPosted: Tue Jun 27, 2006 7:08 pm    Post subject: Re: MagLite, Krypton bulbs and NiCd batteries Reply with quote

Anonymous wrote:
Quote:
I have a Mini MagLite that takes 2 AA alkaline cells.
It uses a small krypton bulb. The instructions say
to avoid rechargeable batteries
[...]

As far as I know, the NiCds actually have a smaller
voltage rating than standard alakaline batteries (1.3V
versus 1.5V).

Why can't you use NiCds with the MagLite krypton bulbs?

As with all filament bulbs, as soon as you under-run them the light
fails
-
don't forget you are making aspectrum of light, but only a minor
part is in

the visible, the rest is IR. As volts fail so the derrived spectrum
moves

to the red and then to IR. Therefore at 3V you get loads of light,
at 2.4V you just get heat.

I need more explanation given this: the bulb is DEAD. It turned
black and

Maybe it just reached the end of it's natural life anyway. Maybe running it
warm, causes the ingredients to condense on the filament and attack it.

Quote:
when I try it with regular alkaline batteries it does not glow at
all. Are
you
saying that at low V there is MORE heat (less light) than at higher V
and
that the filament gets vaporized but at higher (proper) V the heat is
LESS

and the juice goes into light INSTEAD of heat?

There won't be more heat - R will change slightly with temperature, but in
general I=V/R, V drops so I drops, so total watts drop, you just get a warm
bulb.

If you compare with "normal" filament bulb at it's correct voltage, at least
90% of it's output is *not* in the visible. Hence the tricks of adding
different gases, halogens, etc. to improve the visible efficiency.

Visible light and IR are just our definitions - it's a continuous spectrum,
just because you can't see IR does not mean it's not light.

Quote:
2.4 V: higher heat - more IR - less visible
3.0 V: lower heat - less IR - more visible
I guess I'd like to see the voltage dependence of the spectra of some
lamps

someplace.

But other filament light bulbs don't seem to fail that way, at least
not cheap-o 40 W - 150 W incandescent bulbs for table lamps or
ceiling fixtures.

All bulbs red shift with lower voltage. That's why so called "long life"
bulbs (i.e 2000h) are more yellow. Compare that with a Photoflood bulb
which is effectively a well over-run bulb, in order to get something more
approaching daylight (and they don't last very long!)

Quote:
Why krypton bulbs? SOME other flashlights can run off of alkaline,
NiCd
or NiMH batteries w/o such an obvious shortened lifetime.

What about xenon or halogen bulbs?


-=-
This message was sent via two or more anonymous remailing services.

--
Ron Jones
Process Safety & Development Specialist
Don't repeat history, unreported chemical lab/plant near missesa at
http://www.crhf.org.uk Only two things are certain: The universe and
human stupidity; and I'm not certain about the universe. ~ Albert
Einstein
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beav
science forum addict


Joined: 18 Oct 2005
Posts: 63

PostPosted: Tue Jun 27, 2006 2:09 pm    Post subject: Re: MagLite, Krypton bulbs and NiCd batteries Reply with quote

On 26 Jun 2006 21:18:50 -0000, Anonymous
<BigappleRemailer@bigapple.yi.org> wrote:

Quote:
I have a Mini MagLite that takes 2 AA alkaline cells.
It uses a small krypton bulb. The instructions say
to avoid rechargeable batteries
[...]

As far as I know, the NiCds actually have a smaller
voltage rating than standard alakaline batteries (1.3V
versus 1.5V).

Why can't you use NiCds with the MagLite krypton bulbs?

As with all filament bulbs, as soon as you under-run them the light fails
-
don't forget you are making aspectrum of light, but only a minor part is in

the visible, the rest is IR. As volts fail so the derrived spectrum moves

to the red and then to IR. Therefore at 3V you get loads of light, at 2.4V
you just get heat.


Hmmmm! interesting!

Quote:

I need more explanation given this: the bulb is DEAD. It turned black and

when I try it with regular alkaline batteries it does not glow at all. Are
you
saying that at low V there is MORE heat (less light) than at higher V and
that the filament gets vaporized but at higher (proper) V the heat is LESS

and the juice goes into light INSTEAD of heat?

2.4 V: higher heat - more IR - less visible
3.0 V: lower heat - less IR - more visible
I guess I'd like to see the voltage dependence of the spectra of some lamps

someplace.

But other filament light bulbs don't seem to fail that way, at least not cheap-o
40 W - 150 W incandescent bulbs for table lamps or ceiling fixtures.

Why krypton bulbs? SOME other flashlights can run off of alkaline, NiCd
or NiMH batteries w/o such an obvious shortened lifetime.

What about xenon or halogen bulbs?


-=-
This message was sent via two or more anonymous remailing services.

i imagine Xe would be the same. i'm guessing that a halogen bulb
would be different. if i understand the functioning mechanism, theres
a spot of I2 added that cools onto the W filament then evaporates when
power is applied, leaving a clean W filament. the bulb eventually
fails when a W weak spot finally burns thru.

long story short, it should perform longer, and not be current
sensitive.

of course.. i could just be nuts..
Quote:


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Anonymous
Guest





PostPosted: Mon Jun 26, 2006 9:18 pm    Post subject: Re: MagLite, Krypton bulbs and NiCd batteries Reply with quote

Quote:
I have a Mini MagLite that takes 2 AA alkaline cells.
It uses a small krypton bulb. The instructions say
to avoid rechargeable batteries
[...]


Quote:
As far as I know, the NiCds actually have a smaller
voltage rating than standard alakaline batteries (1.3V
versus 1.5V).

Why can't you use NiCds with the MagLite krypton bulbs?

As with all filament bulbs, as soon as you under-run them the light fails
-
don't forget you are making aspectrum of light, but only a minor part is in

the visible, the rest is IR. As volts fail so the derrived spectrum moves

to the red and then to IR. Therefore at 3V you get loads of light, at 2.4V
you just get heat.

I need more explanation given this: the bulb is DEAD. It turned black and

when I try it with regular alkaline batteries it does not glow at all. Are
you
saying that at low V there is MORE heat (less light) than at higher V and
that the filament gets vaporized but at higher (proper) V the heat is LESS

and the juice goes into light INSTEAD of heat?

2.4 V: higher heat - more IR - less visible
3.0 V: lower heat - less IR - more visible
I guess I'd like to see the voltage dependence of the spectra of some lamps

someplace.

But other filament light bulbs don't seem to fail that way, at least not cheap-o
40 W - 150 W incandescent bulbs for table lamps or ceiling fixtures.

Why krypton bulbs? SOME other flashlights can run off of alkaline, NiCd
or NiMH batteries w/o such an obvious shortened lifetime.

What about xenon or halogen bulbs?


-=-
This message was sent via two or more anonymous remailing services.
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Ron Jones
science forum Guru Wannabe


Joined: 16 May 2005
Posts: 175

PostPosted: Mon Jun 26, 2006 7:19 pm    Post subject: Re: MagLite, Krypton bulbs and NiCd batteries Reply with quote

TwistyCreek wrote:
Quote:
This might be more for sci.physics or electronics,
but I follow sci.chem. Maybe someone here knows
the answer.

I have a Mini MagLite that takes 2 AA alkaline cells.
It uses a small krypton bulb. The instructions say
to avoid rechargeable batteries (NiCds; I don't
remember what it said about rechargeable alkalines,
NiMH or Li-ion rechargeables.)

I wanted to test some new NiCds to see how long they'd
last and started a flashlight test. It didn't take too
long for the bulb to dim and eventually turn black
and stop working.

As far as I know, the NiCds actually have a smaller
voltage rating than standard alakaline batteries (1.3V
versus 1.5V).

Why can't you use NiCds with the MagLite krypton bulbs?

As with all filament bulbs, as soon as you under-run them the light fails -
don't forget you are making aspectrum of light, but only a minor part is in
the visible, the rest is IR. As volts fail so the derrived spectrum moves
to the red and then to IR. Therefore at 3V you get loads of light, at 2.4V
you just get heat.


--
Ron Jones
Process Safety & Development Specialist
Don't repeat history, unreported chemical lab/plant near missesa at
http://www.crhf.org.uk Only two things are certain: The universe and
human stupidity; and I'm not certain about the universe. ~ Albert
Einstein
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Gordon
science forum Guru Wannabe


Joined: 12 May 2005
Posts: 115

PostPosted: Mon Jun 26, 2006 5:26 pm    Post subject: Re: MagLite, Krypton bulbs and NiCd batteries Reply with quote

On 26 Jun 2006 16:47:33 -0000, TwistyCreek <anon@comments.header>
wrote:

Quote:
This might be more for sci.physics or electronics,
but I follow sci.chem. Maybe someone here knows
the answer.

I have a Mini MagLite that takes 2 AA alkaline cells.
It uses a small krypton bulb. The instructions say
to avoid rechargeable batteries (NiCds; I don't
remember what it said about rechargeable alkalines,
NiMH or Li-ion rechargeables.)

I wanted to test some new NiCds to see how long they'd
last and started a flashlight test. It didn't take too
long for the bulb to dim and eventually turn black
and stop working.

As far as I know, the NiCds actually have a smaller
voltage rating than standard alakaline batteries (1.3V
versus 1.5V).

Why can't you use NiCds with the MagLite krypton bulbs?

(I can't find the answer on the MagLite web pages, some
of which say "Coming Soon". Not all MagLites use the
krypton bulb: some use xenon, halogen or 'hi-intensity
bi-pin' bulbs.)

The problem with this setup is that it is not a light emitter,

but rather, it is a dark absorber. If you doubt this, just cut
one of the discharged NiCd cells open and you will see that it is
full of all that absorbed darkness.

Now, if you were to try recharging these cells you would be
extracting all that previously absorbed darkness and...how would
you dispose of it??? Wink
>
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TwistyCreek
science forum beginner


Joined: 19 Dec 2005
Posts: 29

PostPosted: Mon Jun 26, 2006 4:47 pm    Post subject: MagLite, Krypton bulbs and NiCd batteries Reply with quote

This might be more for sci.physics or electronics,
but I follow sci.chem. Maybe someone here knows
the answer.

I have a Mini MagLite that takes 2 AA alkaline cells.
It uses a small krypton bulb. The instructions say
to avoid rechargeable batteries (NiCds; I don't
remember what it said about rechargeable alkalines,
NiMH or Li-ion rechargeables.)

I wanted to test some new NiCds to see how long they'd
last and started a flashlight test. It didn't take too
long for the bulb to dim and eventually turn black
and stop working.

As far as I know, the NiCds actually have a smaller
voltage rating than standard alakaline batteries (1.3V
versus 1.5V).

Why can't you use NiCds with the MagLite krypton bulbs?

(I can't find the answer on the MagLite web pages, some
of which say "Coming Soon". Not all MagLites use the
krypton bulb: some use xenon, halogen or 'hi-intensity
bi-pin' bulbs.)
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