# Primos Top Gun Headlamp, a new breakthrough in efficiency?



## mmeiser (Oct 25, 2009)

Primos Top Gun Headlamp

http://www.cabelas.com/p-0072753519417a.shtml

150 lumen for 6 hours on TWO AA !!??

low is 85 lumen for 12 hours

I'm pretty familiar with the most efficient LED lights on the market (i.e. Cree seems to be the current leader in this range) but how's that kind of brightness possible on only two AA?

I know nothing of Primos, indeed a google search against the forums here finds only three references to the name Primos on the entire site.

What's more the light bulb type is not stated and the product is listed as back ordered, otherwise I might have already ordered one.

I have a cheap River Rock 6-volt that originally ran on two CR123 at 136 lumen. They claimed six hours. I converted it to 4AA and it gets about six hours before starting to dom.

I've also seen the specs and conversation here on the new Fennix HP10. It's supposed to run 225 lumen for 2.5 hours on 4AA, and 120 lumen for 7.5 hours.

This Primos is either a big misprint, straight up lying (beyond exaggerating), or truly a breakthrough in LED efficiency.

Does anyone have one yet? 

Any thoughts?

Anything else that even comes near the claimed efficiency of this light?


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## cave dave (Oct 25, 2009)

Sounds like the old LED marketing technique used by unregulated lights that start out bright but then quickly dim so the light runs for a long time but the peak brightness only lasts a few minutes.


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## TooManyGizmos (Oct 25, 2009)

.
????? 
From the "filtered Gree Light" picture in your link , the front Photo of the LED looks like it has a 6 die ...!... LED.

Anyone else notice that ?

.


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## nikon (Oct 26, 2009)

TooManyGizmos said:


> .
> ?????
> From the "filtered Gree Light" picture in your link , the front Photo of the LED looks like it has a 6 die ...!... LED.
> 
> ...


 
That's what the standard Cree XR-E die looks like in closeup.


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## Patriot (Oct 26, 2009)

There's no way that XR-E is regulated for 6 hours. 

Will Primos started as a hunting call manufacturer and has now grown into all kinds of hunting accessories. I own several of their products and I'm usually very happy with them. Not all of their designs are Primos originals but I believe this headlamp is because I've never seen it before. Obviously the big problem with enthusiast like us is that we like fully regulated lights and if this light is regulated they're not providing accurate published run-times. The average sportsman probably won't know or care, plus people will probably think the filter deal is cool.


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## TooManyGizmos (Oct 26, 2009)

The silly add neglects to even say anywhere that it's an LED light.


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## half-watt (Oct 26, 2009)

no experience w/this HL, so please take the following words with a grain of salt. 

150lm, if accurate for even emitter lumens would undoubtedly be a newer generation LED. 

Agreed, that the burntimes are mighty suspect. However, unlike the handhelds that we on CPF are used to which often measure burntimes to 50% of the starting light output, HL Mfrs have jumped on a standard, first used in Europe, IIRC, which measure burntime down to a measly 0.25lux at, IIRC, 2 meters (approximately the light output from a full moon on a cloudless night).

This 0.25 lux is fine if you are using the HL for task/proximity lighting or simply looking at your foot placement, or meandering a simple, non-technical, well-marked footpath, but on higher powered HLs this 0.25lux "cut-off" is next to worthless, IMO, if you were using the HL for nighttime trail navigation under tree cover or on a cloudy night. My age degraded low light vision simply can't pick out low contrast, faded blazes marking turns/bends in an unfamilar trail 30' ahead with 0.25 lux. Maybe some young'uns can???

Figure, unregulated on alkalines, you could be down to 25% of the initial output, depending upon current draw and thermal management issues of both the cells and the LED, in 30minutes (or an hour at most) on HIGH power, is my *GUESS* based upon experience with similar unregulated HLs (most earlier generation LED HLs, but current draws were probably similar - just less light out from the earlier generation LEDs). 

NiMH cells are probably the way to go, or Li primary cells if the light can tolerate the increased working voltage (only 2cells instead of 3cells in series, so, the diff. is *not* as great - might work??? additionally, one could just use LOW/85lm setting until cell voltage drops a bit - not sure of the electronics involved with this HL, but this sol'n works for some other lights, depending upon the design of their electronics).

i was intrigued with this HL some weeks ago when i first saw it, but decided to "pass" on it for the reasons i stated above. The Fenix HP10 is my preferred HL at this point in time for other than ultralight, EDC (Zipka-Plus), or task/proximity usage.


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## spyderknut (Oct 27, 2009)

:shakeheadPrimos sounds like a blatant attempt to rip off Primus.


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## GaryF (Oct 27, 2009)

spyderknut said:


> :shakeheadPrimos sounds like a blatant attempt to rip off Primus.



Similarity noted, but no, Primos is a 25+ year old company that is named after the founder.. Primos As for the lumens and runtime, just another unrealistic claim.


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## cave dave (Oct 27, 2009)

Even with the latest LED's I can't see running an LED at that brightness inside a plastic case with no external heatsink. The LED would suffer from permanent loss in brightness from overheating.


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## PhantomPhoton (Oct 28, 2009)

Well let's do some rough math...

Assume lithium primary cells (and be overly generous with our estimates)...
1.7v * 3.0Ah = 5.1Wh (although we know that the voltage doesn't stay at 1.7 ; but we'll just keep the math simple and go with that)

5.1Wh * 2 [cells] = 10.2Wh

burn time = 6 hours...
10.2 / 6 = 1.7 Watts of drive energy can be given

Assume an LED with a VF around 3.3V... (again generous assuming an XR-E)

1.7W / 3.3V = .5A current to the LED (^ this result makes the above assumption of VF especially generous for an XR-E^)

At 500mA the maximum theoretical potential of a Cree XR-E R2 is ~152.5 lumens. (*whew* just made it)

125% of max potential (guestimated from the XR-E spec sheet) of the R2 bin (122 max lumens) = 152.5

Now we have to factor in effeciancy losses from the boost converter. Assume a 5% loss (again generous for a boost circuit) and we get ~144 lumens. Doh! And that was with way too much generosity in our estimates.

I'd say as long as they're not using Cree R5 XP-G's in these lights that this myth is busted! We can tell this headlamp, like 95% of all the other ones out there, isn't adequately heat sunk.

However, we are really close to six hours at 150 lumens from 2xAA. Even without being generous if a manufacturer or individual were to use top notch parts and proper heat sinking.


Oh and as an afterthought... 85 lumens is a low? WTF? Not where I come from.
We can tell just from this that this light is almost certainly not using a top notch driver...
nor was there a lot of thought and real world use/ expertise put into its design.


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## Patriot (Oct 28, 2009)

spyderknut said:


> :shakeheadPrimos sounds like a blatant attempt to rip off Primus.




May sound like it but it's not. As mentioned in post #5, Primos is Will's last name and Primos is an extremely ethical organization.


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## cave dave (Oct 29, 2009)

The Quark 2AA uses a high end fully regulated driver and a pretty good R2 Cree Led and it's spec are:

High: 70 lumens for 5 hours (250ma)
Max: 170 lumens for 1.3 hours (700ma)
Note: Quark Lumen values are measured OTF in a real lab quality integrated sphere over several random samples and then averaged.

If *any *competitor is claiming significantly better results they are *lying, *plain and simple. The use of the latest and greatest most efficient LED on the market (Cree XPG R5) would result in a about a 21% increase in the above lumen values. A pure buck driver would be slightly more efficient than the buck/boost of the quarks but the runtime difference would be measured in minutes not hours.


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