Xenon has better burntime than Krypton? (MagLite)

[UnknownVT]

The lamp specs for D-Cell MagLites -

at the D-Cell MagLite lamp spec page
seems to show that the Xenon lamps not only are brighter than the standard Krypton lamps (not surprising) -
but their battery on-times are longer too
(14-16 hours vs 9-10 hours of Krypton)-

So is this true that the Xenon lamps not only burn brighter - but have longer battery life too?

 

[js]

In general, it is hard to say anything definite about xenon vs. krypton, except that if everything else is comparable the xenon lamps will have a slightly longer filament life, so this can be translated into the same life but more brightness.

However, the phyics which govern tungsten-halogen lamps are very complicated and complex and inter-related. So, you can't say in general because the other factors are NOT going to remain the same. It is possible and even likely, that in some cases the fill gas of choice will be krypton over xenon.

The atomic weight of xenon is higher, and thus it is better at suppressing the vaporization of tungsten atoms from the filament. That much I can tell you. But how this ties in with all of the other considerations that enter into lamp design is beyond me.

 

[UnknownVT]

[ QUOTE ]
js said:In general, it is hard to say anything definite about xenon vs. krypton, except that if everything else is comparable the xenon lamps will have a slightly longer filament life, so this can be translated into the same life but more brightness.

[/ QUOTE ]

Have I misunderstood this -
does MagLite's "Battery ON-time" mean the life of the bulb,
as opposed to what I thought the battery runtime?

Surely a standard Krypton bulb-life is more than 9-10 hours?

 

[js]

I have no idea. For all I know, those are runtimes.

Plus, if these are not halogen lamps, those could really be bulb life-times to 85 percent down, or some such value. Non-halogen lamps will blacken with time. The stock mini-mag lamp becomes insufferably dim after only 8 or 10 hours of use.

 

[JimH]

Re: Xenon has better burntime than Krypton? (MagLi

Xenon bulbs have a higher efficacy (lumens per watt) than krypton. Driven at spec xenon will be brighter than krypton. Now the flip side - krypton bulbs can be overdriven more than xenon so a krypton bulb can be brighter than a xenon bulb when overdriven enough.

I have been using Carley krypton bulbs lately. These things are really bright when overdriven to the max. I'm still experimenting to figure out what the max is. The key is going to be using a soft start circuit for severely overdriving them.

 

[BlindedByTheLite]

Re: Xenon has better burntime than Krypton? (MagLi

i don't think anyone's really answering Vincent's question here. what i understand he's asking is, if you take two brand new Maglites with a new set of batteries in each, with a xenon bulb in one, and a krypton bulb in the other, turn them on @ the same time and point them @ the ceiling, which light will go out first?

 

[AW]

Re: Xenon has better burntime than Krypton? (MagLi

My little test result : xenon is more battery hungry than Krypton /ubbthreads/images/graemlins/huh.gif

JimH,

I had two 4 cell krypton bulbs died within an hour, being driven with 6 cells.

 

[twentysixtwo]

Re: Xenon has better burntime than Krypton? (MagLi

Jim - very interesting, do you know why this is?, I had made that same observation by messin' around with overdriving bulbs - so far the most overdriven krypton bulb I have is a kpr112 (5 cell) run off of 8 AA's.

meanwhile flashed 2 halogens and blckened numerous vacuum bulbs. Only tried one Xe bulb, and I don't think I reached the limit

 

[xpitxbullx]

Re: Xenon has better burntime than Krypton? (MagLi

I assure you that the posted specs for runtime by maglite is far from the truth.

Runtime to 50% output tends to be under half an hour with all models.

Jeff

 

[UnknownVT]

Re: Xenon has better burntime than Krypton? (MagLi

[ QUOTE ]
xpitxbullx said:
I assure you that the posted specs for runtime by maglite is far from the truth.
Runtime to 50% output tends to be under half an hour with all models.

[/ QUOTE ]

According to the runtime plot at FlashlightReviews.com
for the 3D MagLite:

shows a shade over 1 hour to 50% brightness -
but one really has to look at the graph - because although the light does show diminishing brightness over time - it does not have th drastic drop as in the first 1/2 to 1 hour and manages to give some light all the way out to nearly 11 hours - which would probably account for MagLite's own figures of 9-10 hours.
Even at 10 hours it is about 15% of the initial light output which is actually still quite useful
(10 hours = approx 6 lumens - which is brighter than a MiniMag 2AA initial brightness on fresh AA batteries!)

Roy's runtime Plot for the MiniMag 2AA:

also shows the fast initial drop within the first hour or two. Its runtime to 50% is about 2 hours - but manages to still give diminishing light out to about 7 hours where it is probably "pitiful". But at the 6 hour mark it is about 24% of initial output - which would put the light level at about 1.3 lumens - enough to navigate around a room by. So again still gives MagLite's figure of 5.5-6 hours "battery On-time" some credence......

From what I've read on the MagLite website and their downloadable pdf brochure -
it would seem that "Battery On-Time" means the battery-life or runtime - and most probably until they "die", as opposed to 50% of initial brightness.


So coming full circle back to my original question - looking at the MagLite specs for their lamps - reproduced in the opening post -
It seems that the brighter Xenon lamps have longer spec'd battery-life runtimes compared to the standard Krypton lamps.

This seems counter to what I would have expected -
the Xenon lamps are usually more power hungry than the equivalent Krypton lamps.

Comments?

 

[JimH]

Re: Xenon has better burntime than Krypton? (MagLi

[ QUOTE ]
AW said:
JimH,

I had two 4 cell krypton bulbs died within an hour, being driven with 6 cells.

[/ QUOTE ]

Are you using cheapo Mag replacement bulbs or are you using Carley bulbs specifically designed for rechargable batteries (i.e. Carley 600 series lamps)?

 

[xpitxbullx]

Re: Xenon has better burntime than Krypton? (MagLi

That short runtime info is what was mailed to a member here from maglite themselves. They asked about the runtime to 50% of one of thier lights and Maglite replied "20-30 minutes"

Just what I had read here.

Jeff

 

[UnknownVT]

Re: Xenon has better burntime than Krypton? (MagLi

Problem solved.

Xenon does not have longer battery-life runtimes than the equivalent Krypton lamp -

e-mail response from MagLite:

>From: <[email protected]>
>To: vincent
>Subject: Maglite.com Website Visit - Your Feedback - Control Number F-150182
>Date: Thu, 17 Mar 2005 16:07:39 -0800
>
> Vincent:
>
>Sory, that is a missprint. The xenons consume about 10% more energy than the LWSA lamps.
>
>Don
>
>---------- ORIGINAL MESSAGE ----------
>TO : Mag Instrument, Inc. Web Site (www.magmail.com)
>FROM : vincent
>RECEIVED: 3/15/2005 11:45:25 PM EST
>
>The Lamp Specs for the D-Cell MagLites at:
>
>http://maglite.com/lampspecs_dcell.asp
>
>Show the Xenon lamps (LMSA series) to have longer battery On-times than the standard LWSA Krypton lamps.
>
>Does this mean that batteries last longer using the Xenon LMSA lamps over the Krypton LWSA lamps
>or
>that Xenon lamps have a longer Bulb-life over the Krypton versions?
>
>Thanks,
>
>Vincent