How many Lumens?

[daddypaul3]

i just got this bad boy off ebay

£18.99 free delivery & from a UK supplier
bright as F**k, sure it will come in handy on those dark mornings off road

 

[Fab Foodie]

i have been using a 3 cree torch from Tesco's for last 3 years never been an issue , just not enough spread of light

I've done many a night ride on a pair if those. Do they still do them?

 

[TheDoctor]

I've got a Cree LED one off Ebay. It's just got the one LED and it is indeed bright as an incredibly bright thing.
The 3 LED jobs must be visible from Mars!

 

[Sham69]

Tried a few LED lights over the years and I'd say something around 500 lumens as a minimum if you'll be facing oncoming motor vehicles (surprising how significantly oncomming motor vehicle lights reduce your own ability to see the road ahead). Maybe a light with a single SSC P7 or Cree XM-L T6. I'm afraid the advertised lumen rating for many lamps is usually optimistic. A light advertised as, say, 1000 lumen is often found to be around 700.

I've also tried pairs of torches which work OK but, as an earlier posted said, they often don't give enough spread. Currently, I'm using a two Cree XM-L U2 lamp and it's great - makes for very relaxed cycling at speed on pitch black, narrow, windy country lanes but always be prepared to dip or dim the lamp for oncomming traffic and pedestrians. One advantage of using very bright lamps on dark roads is that oncomming vehicles treat you like another motor vehicle and will actually stop to let you pass instead of hogging narrow roads (happens to me a lot on certain blind bends) and forcing the cyclist to give way as usual . Means I do more milage during the dark than during daylight as I feel safer and actually manage higher average speeds too.

 

[mjr]

You can see better with these 1000 lumen lights, but remember that you are also dazzling anyone coming the other way. Ask yourself whether you want a blinded motorist heading for you on a narrow lane.

Having a light that is unable to avoid dazzling other road users is illegal as well as anti-social.

I'd drop @andrew_s's 200 lumen threshold to 120 lumen if the lens is good (my Cateye HL-EL 550 with a LED "bulb" is 120 lumen, as I understand it and is more than enough both in town and in the country) and you're riding on-road only, but in the current stupid stupid lumen-bombing marketing war in this country, you're unlikely to find a bike light with a good lens. The newer Cateye 530 I saw seemed to have a junky plain round lens.

Importing decent lights from countries with more winter cyclists (Germany, Denmark, the Netherlands) seems the best way to get lights that are good, cheap and legal.

 

[Sham69]

I'd drop @andrew_s's 200 lumen threshold to 120 lumen if the lens is good (my Cateye HL-EL 550 with a LED "bulb" is 120 lumen,

Clearly, I need to eat more carrots!

 

[daddypaul3]

it says up to 6000 lumen for this light on ebay with all 3 led's on full power . think that it might dazzle people instead of lighting the way for me

 

[Sham69]

it says up to 6000 lumen for this light on ebay with all 3 led's on full power . think that it might dazzle people instead of lighting the way for me

According to CREE's website, each XM-L U2 LED (the LED type used in this lamp - if it's the same one I'm looking at on ebay) will give a minimum output of 975 Lumens if driven to the max. current limit of 3 Amps. No cycle light LED driver circuits I've tested so far have ever driven an LED to the max. current (unless 'modded' by the user) but even if all three LEDs are driven to the max. the light output would be around 3000 Lumen in total. At best guess, this lamp will output no more than 2500 Lumens when cold and drop a little as it warms up. Way short of the 6000 Lumen claim but still very, very bright indeed.

 

[daddypaul3]

its these

• 3×CREE XM-L T6 extra white LED

not sure if its the same ones

 

[daddypaul3]

think ive got to the bottom of it

3 x CREE XM-L T6 on round PCB
3x Cree XMLAWT-0000T6051 auf Rundplatine

Diameter: 34.0
Viewing Angle: 125°
Height: 6.0 mm
Emitting Color: white
Housing Color: white
Lumen min.: 840
Lumen max.: 2985---------------> not a bad estimate sham69
Kelvin min.: 5700
Kelvin max.: 6100-------------------------------------------------------------- think its dodgy info on ebay !! 6100 kelvin not Lumens
mA min.: 700 mA
mA test.: 700 mA
mA typ.: 700 mA
mA max.: 3000 mA
V min.: 8,7 V
V typ.: 8,7 V
V max.: 12 V
Watt: 6,09 W

Datasheet: Click here!
Binning & Labeling: Click here!