XR-E R2 - Questions answered


Flashlight Enthusiast
Feb 15, 2009
Melbourne - Australia
Well , the longer you hang out at CPF , the more you see the same questions asked .
1/ How bright [ output ]
2/ How far will it throw
3/ How long will it run
4/ What batteries to use
5/ :thinking:

Well , I will try and explain things as best as possible :

1/ How bright = CREE R2 (114-120 Lumens @ 350ma) :duh2:
Now factor in the variables , how good is the emitter , how much current will it tolerate , how well was it mounted on the star , how well was the star mounted in the light/drop in , how good is the driver , your battery choice , how good is the lens , is the bezel blocking output .

So the answer is , we don't know , buy the light and tell us !
In theory , at one amp you should see over 300Lumen , but thats only theory , in reality the more current you feed the emitter the more heat is generated rather than light , and thus you get diminishing returns as you increase the current . Now you would think that some LED's will be better than others , and this is true , one may be outstanding , and one may be very ordinary .
This is simply a fact of life , and manufacturing , we cant make anything 100% exactly the same , and there is the pot luck factor .

So what to expect , actually anything from 220 to close to 300 Lumen depending on all the variables . [ and the pot luck factor ]
Dont worry about what other people say , you get what you get .


Throw is very dependent on how bright/hot the focused part of the light [ hotspot ] in the middle of the beam is .
A lot of people measure this with a light meter at 1 meter distance .
So often you will see quotes for 5000Lux @ 1 Meter or such , this is not output , but rather the intensity of the hotspot , which to some extent will determine how far the beam will be effective , or throw .

So how far will a R2 throw , is very much dependent on how hard the emitter is driven , and the design of the light . A P60 drop in at 1A may be good for 100 Meters or more , again very much dependent on the actual intensity of the hotspot . I have one R2 that only outputs 220Lumen but the hotspot is 8500Lux , so it throws well , 150 meters and maybe closer to 200 .
Another R2 has much more output , but only 8000Lux for the hotspot , and throws no better than the lower output drop in .

So just because you have more output , does not mean it will throw , its that nasty variable again , and the pot luck factor .

Now just for the heck of it , a well focused thrower at 200 Lumen can have a hotspot close to 20,000Lux and throw 300 meters and then some .
You dont need massive output to throw .

How long will it run

Again , we dont know ?
A lot of spec's for cheaper chinese lights are way out , and there is no way of knowing until you get in there with a multimeter .

Its just a bit of math ,
2 x CR123A , now please dont confuse primary capacity with rechargeable capacity in the CR123A's , a really good primary might be twice the capacity of a rechargeable , which is why some swear by Primaries .
Any how , lets call the primary 1000mA , the rechargeable 600mA ...
voltage also comes into play , Primaries 3v to RCR123A 4.2v fully charged .
Most drivers will behave like this , the more voltage , the lower the AMPs .
So while a primary may have to feed closer to 1A the rechargeables may be down as low as 0.6A to start with [ 6v VS 8.4v ]
Now that same light might also take a 18650 , which might have to feed the driver 1.4A or more .. Understand ?
6v @ 1A / 1000mA capacity =
8.4v @ 0.6A / 600mA capacity =
4.2v @ 1.4A / 2600mA capacity =
Now thats just an example , but hopefully you will get the gist of it .

What Batteries

Ok some people like the simplicity of Primaries [ 3v Non Rechargeable CR123A ] , and carefully chose lights designed for such batteries .

Others like the rechargeable 4.2v CR123A as the higher voltage helps keep a flatter output from the light .


A lot of folks like this option , higher capacity , longer run times , less danger of mixing cells and having an event of explosive nature , also once again one can chose lights specifically made for this battery

Now unfortunately this is a very simplified explanation , as those nasty variables actually make it more complicated , so the short answer is ???

Rant over :whistle: