Xenon or Halogen?

Does anybody have a comparison between Xenon and Halogen bulbs as regards brightness and longevity in a 3D Maglite?
I was going to get a GH143 halogen bulb (4V 0.75A) from Reflectalight, then I saw the local supermarket had a "xenon torch" . As the halogen bulb costs £4 and the whole supermarket package cost £2.99 including a spare 3.6V/0.82A xenon bulb and 3 batteries, I wondered if this might be a better option?

I don't know a lot about the differing mag and other PR base bulbs, but I will say this: if you want longevity then driving the bulb at spec or under will give you normal or increased longevity. If you have a bulb that is overdriven per spec you will get greater brightness at loss of some longevity. Typically if you multiply the voltage of the bulb time the current rating you get the wattage the bulb uses at spec. The higher the wattage typically the brighter the light with halogen having a hotter whiter color than krypton at about the same wattage I believe.

Your 4v .75A bulb is about 3Watts while the 3.6v .82A is a 2.592Watt.. essentially the same wattage at those specs. Typically bulbs are rated for 1.2v/cell or a 3.6v bulb is rated for 3 cells while the 4v it rated for 4 cells with some overdrive or 3 cells with less drive than the 3.6v bulb. I would *guess* the GH143 4v bulb would be the brightest on 4D cells with alkalines overdriving it 25% more than a 4.8v bulb would be driven.

Hopefully some of the super bulb gurus will jump in and give you more info, but you may want to do some searches on that particular bulb to see what people say about it.

Thanks. I wasn't sure of the relationship between watt and amps. Using 3 1.3V Nimh D cells, I guess the xenon bulb would give 0.82 * 3.6 = 2.95 Watt, compared to 0.75 * 3.6 = 2.75 Watt for the halogen. Pretty puny compared to my dive lights!

What I don't understand is why the halogen bulb is so much more expensive than the xenon bulb? Is it much brighter or what? Any idea what the specs are for the 3D Mag xenon bulbs?

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SteveAdams said:
Thanks. I wasn't sure of the relationship between watt and amps. Using 3 1.3V Nimh D cells, I guess the xenon bulb would give 0.82 * 3.6 = 2.95 Watt, compared to 0.75 * 3.6 = 2.75 Watt for the halogen. Pretty puny compared to my dive lights!

What I don't understand is why the halogen bulb is so much more expensive than the xenon bulb? Is it much brighter or what? Any idea what the specs are for the 3D Mag xenon bulbs?

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How much do your dive lights cost???

Halogen is added to another gas like Argon, Krypton (Welch Allyn bulbs), or xenon (Carley Halogen' bulbs) to better maintain rated output over the life of the bulb. Read up on info a Carley's site. Carley has a $50 minimum purchase requirement, which is not that difficult to reach considering many of their bulb cost $5-6+ ea. http://www.carleylamps.com/


Country of manufacture, economy of scale; many factors. The Reflectalight bulbs are mainly marketed at bicycle enthusiasts; bike lights like Lupine lighting systems are very expensive in comparison.


Conversion from MSCP (mean spherical candle power) to lumens is accomplished by multiplying by 12.57, ie 1 MSCP = 12.57 lumens.

Ginseng posted the formula's for conversion, rated vs. estimated overdrive voltage/shortened life spans, per Welch Allyn website figures, on one of the M*gchr WA1160 bulb threads (I think). www.walamp.com

You can get M*g bulb specs on their site here:
http://www.maglite.com/highintensity.asp

If you already have 4 C-cell NiMH, you could get a piece of 1in. diameter (25mm for you /ubbthreads/images/graemlins/smile.gif ) PVC pipe cut and put it into the M*g D-body. 4 C-cells = 200mm, 3 D-cells = 195mm. Gets you more voltage in the D-cell on the cheap, at the expensive of 1/2 the capacity of the D-cell. More voltage allows you to run higher wattage bulbs. But if you get a bulb running at around 10watts you can melt the M*g stock plastic reflector.

Ah yes, 'unofficial Ginseng researcher' remembers correctly, it's hidden in this very, very long thread:

MagCharger WA/UCL Now In Stock!!

I dont know much,, but I know for my car i changed the lights to xenon,, and there a lot brighter....

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SteveAdams said:
Thanks. I wasn't sure of the relationship between watt and amps. Using 3 1.3V Nimh D cells, I guess the xenon bulb would give 0.82 * 3.6 = 2.95 Watt, compared to 0.75 * 3.6 = 2.75 Watt for the halogen. Pretty puny compared to my dive lights!

What I don't understand is why the halogen bulb is so much more expensive than the xenon bulb? Is it much brighter or what? Any idea what the specs are for the 3D Mag xenon bulbs?

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Remember that under low currents nimh cells directly off the charger have been know to exceed 1.4v so output will be brighter till they are used up some then they will end up sagging to between 1.2 and 1.3v where most of the runtime of the battery is. As for halogen being more expensive it is because the bulb itself is made of a quartz glass, that and the higher price of the gas inside plus most likely higher production costs associated with making it drives up the price. It is recommended you don't leave oil from your hands on halogen bulbs.. either handle with clean gloves, a cloth and if you touch them wipe them off with rubbing alcohol or the oils will attack the glass when it is heated up.
Halogen also operate at higher temperatures which means whiter light, also I believe they output more lumens/watt than most xenons/standard incans.

There is often confusion about the term "Halogen". Most people think it is a single gas but the term really refers to any one of a small group of related elements which includes chlorine, iodine, bromine, and two or three others. It is one (or more) of these halogens that are added to xenon, krypton or argon lamps as Udaman has described.

Brightnorm

Streamlight and GH Halogen bulbs are advertised as "hard glass" bulbs, the distinction being that "hard glass" is tougher than quartz glass, and less apt to break under hard use.

Bill

Sounds like non quartz bulbs then, I haven't kept up with halogen bulbs but they used to be all quartz glass and required some care in handling. I guess you have to read the packages now to see if there is any handling instructions or are all halogens going away from quartz glass?

Probably most hard use halogen bulbs will be some type of "hard glass". I do not know what type of glass Carley uses in their halogen bulbs.

Bill

Thanks for the info. I'm just getting more confused! I compared the supermarket 3D "xenon" with a standard (borrowed) 2D Maglite and they seemed about the same brightness (I thought the 3D would be brighter). The mag was a lot dimmer with the 3.6V xenon bulb compared to the standard (3V?) krypton bulb.

I may put 4 C cells into the 3D mag. How high can the wattage go before the Maglite reflector would start to melt?

Kinda suck's when a company like mag basically lie's to you.
there site say the xenon is 96% brighter. I just bought a mag 2D to start my experiment's on bulb's both incan and everled, and reflector, glass lens, and the 2X3AAA recharageable's. Thought i would get the new
Xenon first to see how it improve's this light.( Man, these mag 2D's are dim! compared to my MC and E2d)the Xenon is dimmer? VDG

Used to like mag... not anymore. Most people are indifferent... "It produces light and its cheap"

-tom

I am quite happy running a M*g 3 cell Krypton with 4 NimH C cells. I generally do NOT overdrive Xenon bulbs as they have a tendancy to pop.

Many if not most Halogen bulbs I've tried don't make a nice beam for whatever reason.

OK. I wanted to post a few basic things just in case anyone doesn't know and to avoid potential misunderstandings.

First: as udaman states, a "halogen" lamp is a lamp that has a small amount of a halogen, such as iodine or bromine, added to the inert fill gasses. The inert fill gass (or gasses) are some combination of argon, krypton, or xenon. So a "halogen" bulb, may well have xenon as the fill gas. And I very much doubt that any company out there makes a lamp with the very expensive xenon fill gas which is NOT a halogen.

Second: the inert fill gas itself reduces the vaporization of the filament, and thus also reduces the rate at which the tungsten atoms adhere to the walls of the glass bulb and blacken it. But without a halogen in the mix, this WILL eventually happen. One example is the stock mini-mag lamps. They are not halogens, and they inevitably blacken over time; it's that characteristic shinny blackish grey you may have seen. On the other hand, the Nexstar T1 Xenon lamps (which are a drop in replacement for the stock mini-mag lamps) do not blacken over time. Until the moment they blow, those lamps are every bit as bright as they were to begin with.

Third: this non-dimming characteristic of halogen bulbs is because of something called "the halogen cycle". When a tungsten atom adheres to the wall of the glass, a halogen atom comes along and binds with it, and the two of them float around in the fill gas until at some point they come close to the high temperature filament. At this point, the reverse occurs, and the halogen releases the tungsten atom where it re-deposits on the filament. Unfortunately, it does not redeposit in the same place as before, and the thin spots tend to get thinner, and the thick spots thicker, until the filament gets so thin at one place that it breaks (usually at start up). Modern halogen lamps can be run at almost any practical level of over or under drive, and the halogen cycle will still work. Don't worry about flashing your light--just use it. It will stay clear.

Fourth: --and this is really what I wanted to get to-- all other things being equal a xenon/halogen lamp will be slightly brighter and whiter than a krypton/halogen lamp. But that said, I must point out that the filament geometry plays the MOST important role in how a lamp will perform with a given set of batteries. The LENGTH of the filament is proportional to the VOLTAGE needed to produce a given filament temperature (and thus brightness) while the THICKNESS of the filament is directly (but not linearly) related to the CURRENT the lamp will draw at any given voltage. Xenon lamps are not more likely to "pop" than krypton lamps. The length and thickness of the filament is what determines how under or over driven any given lamp is at any given voltage.

Same goes for beam profile and characteristics: whether or not a lamp is filled with xenon or krypton really has almost nothing to do with whether or not the beam will have artifacts or not, or how smooth or round it will be. The filament geometry and reflector geometry and surface determine that.

Jim,

Excellent primer on this subject

BN

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SteveAdams said:
Thanks for the info. I'm just getting more confused! I compared the supermarket 3D "xenon" with a standard (borrowed) 2D Maglite and they seemed about the same brightness (I thought the 3D would be brighter). The mag was a lot dimmer with the 3.6V xenon bulb compared to the standard (3V?) krypton bulb.

I may put 4 C cells into the 3D mag. How high can the wattage go before the Maglite reflector would start to melt?

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It's no suprise that you were disapointed. The 3.6 volt bulb was badly under powered by the 3 volt light. The 3.6 was probably designed for ni-cd, not alkalines.

You can buy xenon bulbs that are no brighter than the stock krypton bulbs, but you can also find them much brighter. The Dorcy Spyder, for instance has a cute little xenon bulb that kicks out a lot of light.

Daniel

If I used a 1.7Amp 6 Volt bulb with 4 Nimh I would get about 8 Watt - would that be noticeably dimmer than if I used a 1.7Amp bulb intended for 4.8 Volts?

Also, how far can you go with a mag before the reflector starts to melt?

Steve, yes, the 6V bulb on 4.8V would be dimmer than a 4.8V bulb on 4.8v, even tho the wattage is the same. The 6V bulb will run cooler and less efficiently at the lower voltage with a yellower beam. Also, if rated at 1.7amps at 6V, it wouldn't draw 1.7 amps at 4.8v. It would be more like 1.36amps (80%, or 4.8/6). Note that the difference in output is primarily due to not running the bulb at rated current. If you used a 6V bulb rated, say, 2.5amp@6v that actually drew 1.7amp at 4.8v, there wouldn't be much difference in output except that the 6V bulb woulb be a little more yellow than normal.

Having said all of that, let me further confuse you. Most bulbs are designed to run on alkaline batteries. This means that a 4 cell bulb is designed to run on 6V, but they are normally rated 4.8v. This dates from the days when carbon-zinc batteries were common and 4.8v approximates the AVERAGE (loaded) voltage during the life of the battery. But NiMH batteries are different. They have a much lower internal resistance that allows them to supply higher currents than the alkalines at normal (500ma & up for bulbs) currents. At 4.8V, the NiMH batteries will run the bulb at rated current. At 1.7amps, the alkaline batteries probably will have enuf voltage drop to the point where the NiMH batteries provide the same current at roughly the same voltage for watts and equal brightness. In fact, the NiMH will work better than the alkalines as they start to run down because they will maintain the 1.2V and rated current throughout most of the charge.

Re the maglite plastic reflector, 10watts is safe according to most reports and 12watts isn't. The grey area in between allows for intermittant use, even 5-10 minutes at a time, without melting the reflector. Note that actual wattage and heat output varies a lot between bulbs of the same nominal wattage (halogen would have lower heat output for a given amount of light).

Steve,

For 4 NiMH cells, the voltage starts at about 5.6 volts, plateaus at around 4.8, and ends at around 3.6 volts.

The voltage rating alone of a bulb is of little help; you also need the hours of life rating to make sense of it (or the CCT). What you want is a lamp INTENDED for 4.8 volts (and not 6) which also has a short-ish life time (40 hours or less). Or you could take a lamp rated at 3.6 volts with a 500+ hour life rating and use it with 4 NiMH, which would give you a nice bright white light. Also, between any two lamps with voltage and lifetime stuff being equal, the more the current draw, the more light.

In regards to your specific question, if it didn't make it clear, what I'm saying is to use the bulb intended for 4.8 volts.