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Discussion Starter · #1 · (Edited)
has any one seen these before? http://www.four4th.co.uk/index.html

The light looks very good but I think their calculations are way off, they claim 1200 lm from 4 XP-E R2's and a 3.5 hour burn time with a 14.8 2.6Ah battery pack.

I calculated it from the cree datasheets and worked out they'd have to run the XP-E R2'2 @ about 1100ma to get 1200lm and with that battery pack they'd only get 2.5 hours on max.

I think i've worked out why they got their output wrong they've added 170% to 114.
 

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It's not miss selling, it is 'marketing'.
These is a key difference (giver or reciever)

If they collimate the light to be a tigheter spot the lumen will go up (I may have got lumens/candella mixed up again, I am sure someone will correct me)

I would be 1/10 of these companies quotes correct figure.
 

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Discussion Starter · #3 · (Edited)
CaveGiant said:
It's not miss selling, it is 'marketing'.
These is a key difference (giver or reciever)

If they collimate the light to be a tigheter spot the lumen will go up (I may have got lumens/candella mixed up again, I am sure someone will correct me)

I would be 1/10 of these companies quotes correct figure.
No They are quoting the manuractures claimed out put for the XP-E and they have miss calculated the lumen level @ 700ma
And they can be prosecuted under the trades description act. If there going to quote claimed figures like the rest of us the least they can do is get them right.
 

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I'm with the OP, those figures will never be reached by this light. They claim 1200 Lumens out of 4 XR-E's - even the always "optimistic" Lupine only claims 1100 Lumens for their latest XP-G Wilma. At the same time Lupine rates the Wilma at 17 watts and their light head weighs 112g. Say the Four4th Light "only" exaggerates as much as Lupine does, than they would probably have to burn around 20 watts with the XR-Es to get to 1200 lumens - in a 63g light head. No way such as small head is going to dissipate so much heat.
And as the OP said, the runtimes don't add up either.

It's a shame that they have to spoil such a nice light with those bs marketing figures.
 

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I agree that it's a shame they had to spoil it as it just makes you wonder what you can believe.
They have some great batteries that I like the look of but can I trust a company that tells porkies.

Why not simply tell the truth about a product, if it is good enough it will speak for it's self.
 

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YB
"not round not square"
No, it is certainly more of a not square not round, than not round not square. :D :thumbsup:
Fine design though. I really do like the multi-position helmet mount.
A DIY helmet mount is about the only thing that really hasn't been dialed in here on the board.
 

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Aside from the optimistic output number, it's not a bad looking light.

I suppose it's not entirely out of the question that it could be overdriven to that output, but I'd want a lot more fins (round-bottomed, if I had my way ;) )

What's with the "commuter" lens? Are they focusing all 4 leds through a single aspheric lens? What sort of beam will that produce?

JZ
 

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Nothing on multi drive levels

Nothing mentioned on multiple drive leves or driver at all. I wonder if it's like the Ay-Ups and is just a resistor.... you may get 1200Lumen for 30 seconds then drop to 700-800 and end up with the runtime quoted runtime if you keep measuring down to 100 Lumen.

The comuter lens is described as being 180 * 25 so clearly gives some side visability it is interesting.
 

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Me likey..:) ....Nice looking build for a quad XR-E. One of the best looking ( and functional ) helmet mount designs I've seen in long time. Like everyone else I question the claimed 1200lm output, even if they are over-driving the emitters. I went ahead and sent them an e-mail invite to see if they will answer questions on forum.
 

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Yes it does look a nice little light sits a bit high on the helmet though and why would you need a swiveling mount on the helmet when your neck does the same job . :confused:

Yes it does appear to only have the one output which for the size of it and if they are overdriveing the leds could be an issue for heat .

Is my maths here correct it will be drawing around 1 amp so it would be impossible to get 3.5 hours from a 2.6 amp hour battery :confused:
.
 

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Discussion Starter · #17 ·
I've worked out how they have arrived at 1200 lm and 3.5 hour burn time. They've looked at the cree datasheet and taken the 114 lm @ 350ma the 100% figure and added 170% to get 300 lm @ 700ma, what they should have done is add 70% to 114 to get 193lm @ 700ma. this would give them 775 lm theoretically and the 3.5 hour burn time they are quoting.
 

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As we all know you really want a 5 cell battery (18.5v nominal) in order to stay in regulation with a buck driver and a quad XR-E R2 run on max.

With a 4 cell battery(14.8v nominal) it will start to get dimmer after around an hour, maybe an hour and a half on full with 2.6mah.

I ride with a quad XR-E R2, infact it's my favorite light and get three to three and a half hours on full (1A) with a 5 cell battery and maybe 800/900 lumens.

I do like the Four4th light a lot but the numbers don't add up, maybe the driver they use can work wonders with a 4 cell battery.

Swiveling helmet mount? Up & down, yes but unless you can see via your ears then why left and right?
 

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yetibetty said:
As we all know you really want a 5 cell battery (18.5v nominal) in order to stay in regulation with a buck driver and a quad XR-E R2 run on max.
What driver is that? I am asking because latest XR-E R2 that I have, have about 3.3Vf. Calculating 4S*18650 = 14.8, leds 3.3*4 = 13.2, Vin - Vout = 1.6V, pretty much enough for, say, bflex, isn't? Well, it really depends on the battery quality, of course.
 
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