Although I've been putting halogen lamps in my Maglites for years, I was curious if a xenon lamp would be brighter. I went to the local Radio Shack and picked up a XPR103 xenon lamp, rated for 3.6 V @ 800mW.
The halogen lamps I've been using are made by Eiko. I bought them off eBay, so I have no idea where they came from. For the 3 D Maglite, the halogen lamp is a HPR53 rated at 4.0V @850mA. I was surprised to see not only did the xenon lamp put out less light, it was more noticibly more yellow than the light from the halogen lamp. I was comparing two lights side by side. I swapped bateries between the two lights,and it made no difference. Swapped lamps between the two lights: same story. Hmm... I was expecting a whiter light from the xenon lamp, than from the halogen; especially as the xenon is rated at 3.6 V, and the halogen is rated at 4.0 V
Of course the halogen lamp is higher wattage, so more light from it makes sense. Why the xenon lamp produced a more yellow light is beyond me.
Any ideas? [img]images/icons/tongue.gif[/img] [img]images/icons/frown.gif[/img] [img]images/icons/tongue.gif[/img] [img]images/icons/frown.gif[/img]
If I'm not mistaken, the halogen lamp filament burns hotter (more white?) which is a design characteristic of halogen lamps. Seems the gas content has the ability to redeposit emitted particles back onto the filament - but only at elevated temperatures.
Halogen brighter than Xenon, it's just not that simple! Assuming that all halogen lamps are the same and all Xenon gas filled lamps are the same is the flaw here. Most manufacturers of flashlights and replacement lamps use the absolute cheapest lamps they can get by with. The claims of Halogen and Xenon are the bare minimum gas content they can get away with and remain legal. Speaking as a manufacturer we sell to the industry in very high volume under $1 per lamp. Some manufacturers sell under 50 cents and I've heard of Chinese vacuum lamps at 5 cents. By the time they get to you, the end user, they are $5 each and wildly vary in quality depending on the source.
Now lets assume you are getting the best engineered lamps possible, that would be our HPX (Halogen WITH high pressure Xenon), this would be a tad brighter than a good high pressure Xenon gas only lamp initally. The difference would come after hours of usage where the HPX (or even regular Kryton based halogen) would maintain the initial brightness while the Xenon lamp would slowly darken as the tungsten deposits on the inside the lamp envelop.
Finally, even if all lamp chemistries were equal, there is a difference in electrical properties from manufacturer to manufacturer. Some companies design lamps to quickly discharge batteries (they might have a vested interest in this!) some make lights to be very rugged and have thick shock resistent filaments..... the list goes on and on.
I bet you never guessed that flashlight technology was that involved! Nothing is simple in this world!
the HPR53 at 4V, 0,85A is rated at 60 lumens
the XPR103 at 3,6V 0.85A is rated at 45 lumens
the standard mag3D KPR3C at 3,6V 0.7A is rated at 30 lumens
The HPX30 at 3.6v 0.82A is rated at 45 lumens
I´m using the HPR53 in my 3D so far and even when underdriven usig 3 NiMhs its the best output so far - I would like to try the HPX30 Alan gave us the info on but couldn´t get my fingers on one so far - the beam quality of the HPR53 isn´t too good and I hope the HPX one would be better - the HPX20 in the 2D definetely was some improvement over the HPR52 beamwise while output is pretty similar even when comparing 26 lumens to 34 lumens specwise but again the HPR underdriven due to NiMhs - but maybe Alkalines would be underdriving it too after 1 minute - but at least the live of the bulbs when underdriven is longer ...
Calculating the theoretical lumen loss when underdriving the bulbs you get pretty similar results for all the bulbs above - except obviously the original one.
Ike maybe might give us some idea why WA was designing the original DB bulbs in a way that they are well underdriven IMO - like 5.5V for 4 cell and 4.2V for 3cell - I actually happily run a 3-cell WA bulb from a DB 6AA in my modified straight seriell 4AA/4AAAs using 4 NiMhs and I´m getting VERY nice and bright output. As the bulbs do take .7A it doesn´t make me wonder they suck the voltage down as much - guess this is why the DBs originally had been using the seriel/parallel setup - and maybe this is the answer already.
The DB bulbs were very carefully designed to optimally match the discharge curve of the the Energizer AA cells (in 1998; I believe they have been changes sinced) in their various combinations. The discharge curve varies with the current draw and the design voltage was set at an optimal point on the discharge curve to ballance superior light output with the fact the batteries voltage is always a moving target.
You have discovered you can use incandescent lamps in a wide tolerance around their nominal operating point. You can even predict the performace characteristics using the lamp re-rating tool built into walamp.com
thanks again for the input - appreciated - while you really me interested in the re-rating tool you mention - can´t find it on the site - could you post an URl or way to find it ? I did find some formulas which as far as my mathematical skills go do result in pretty wired results - maybe these are formulas just not being readable as well when posted in plain ASCII. This is the original text:
Vd = Design Voltage Va = Applied Voltage Rerated Life = [Vd/Va]12.0 x Life at Design Voltage Rerated Current = [Va/Vd]0.55 x Current at Design Voltage Rerated Candlepower = [Va/Vd]3.5 x Candlepower at Design Voltage
I think this should read different - or do I miss something - could you explain please ?
And yes - I did found the button to re-rate a bulb - very nice - so my modified straight seriel 4AA/4AAAs do run at >60 lumens - NICE !
The button to re-rate the bulb is what I was referring to. You found the formulas in the datasheets that are used in the re-rating button. If you send me your address, I can mail you a "slide-rule" that does the same thing. I prefer the computer myself.
I tried the hpr50 (Halogen) from RS in the 4-D Mag. A bit whiter, different (crisper) focus, but the lightmeter says it puts out about the same Lumens/meter˛ at it's tightest focus. I took pics, but the "whiteness" difference is indistinguishable in the photos. I'll keep the bulb, but don't know if I'd bother with another one....
Yes, another sleepless night.... [img]images/icons/frown.gif[/img]
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Emeraldwolf: I've successfully located a XPR113 and HPR50 bulbs for the 4D Mag, as well as the XPR103 for the 3D Mag, but can't find the HPR53 <HR></BLOCKQUOTE>
Hi Emeraldwolf. Try here and type HPR53 in SEARCH web page
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Klaus: Gandalf,
the HPX20 in the 2D definetely was some improvement over the HPR52 beamwise while output is pretty similar <HR></BLOCKQUOTE>
Hi Klaus, where did you get that HPX20? I tried TOPBULB and couldn't find it (as well as the HPX30).