Cree Q5 light

[2wd]

Just bought one of these

http://www.ebay.co.uk/itm/320763133118

I'm no expert on cycle lights but OMG this is bright

Not been out on the bike with it yet, but tried it out in the rear garden.

On focus it like one of those big powerful search lights that bounce of the clouds.

With it being drizzly tonight its cutting through the rain and spotlighting a fair old distance.

Zoom out and it fills the garden

For £16.99 I'm well impressed

 

[danger mouse]

Been looking at the same seller. Seems a good deal. Its just the longevity that bothers me.

How long before it falls apart, but for that price you cant worry too much.

 

[2wd]

It looks and feels ok

I havn't found any cause for concern

 

[Davidc]

I've bought 2 of these for a different application, for which the variable focus and battery operation makes them ideal. 2 more on order.

My only concern is whether these lights are too bright for normal road use with a danger of dazzling other road users.

They are amazing lights, it's hard to believe that what is basically a torch running on 3 AAA batteries can be this bright.

 

[2wd]

My only concern is whether these lights are too bright for normal road use with a danger of dazzling other road users.

Thought the very same

I will be angling it downwards a bit which will hopefully avoid dazzling other road users

 

[totallyfixed]

I would be very interested to know what the run time is on high, 260 lumens from 3AAA batteries

 

[andrew_s]

Run time on 3xAAA will be something like 50 minutes on full power, if it keeps constant brightness rather than dimming as the batteries run low.
A Q5 on full power is 3.5W, an AAA has 1Wh in it, and you lose a bit in the drive circuits


I'd recommend getting a 18650 or two, plus a charger.
(eBay, DealExtreme, or a few UK sites such as the photonshop)

 

[PpPete]

I've been looking at this for 18650 powered light with charger.

 

[Svendo]

Run time on 3xAAA will be something like 50 minutes on full power, if it keeps constant brightness rather than dimming as the batteries run low.
A Q5 on full power is 3.5W, an AAA has 1Wh in it, and you lose a bit in the drive circuits


I'd recommend getting a 18650 or two, plus a charger.
(eBay, DealExtreme, or a few UK sites such as the photonshop)

Don't 3xAAAs have slightly more mA/H than a single 18650 has? (~3300 vs. ~2800 albeit at a slightly lower voltage for the AAAs)
Plus AAAs have the convienience, which I had to exploit yesterday, of being obtainable from nearly all shops and garages?

 

[2wd]

I will be trying rechargeable AAAs plus I always carrying a spare set of standard batteries

@ PpPete,thats a very impressive light

 

[Alexvs]

I was looking at the Q5 as looks very good for the price and stacks up with other good lights as far as throw and output. Think I'm going to order one and see how it goes.

PpPete, I was looking at that one also but he states at the bottom to feel sorry for the poor motorist or something like that so guessing a bit too bright for commuting which I'd need it for.

 

[Davidc]

Don't 3xAAAs have slightly more mA/H than a single 18650 has? (~3300 vs. ~2800 albeit at a slightly lower voltage for the AAAs)
Plus AAAs have the convienience, which I had to exploit yesterday, of being obtainable from nearly all shops and garages?

No but the arithmetic's wrong.

The AAAs are in series so a set of 1100 mAH rechargeables give 1100mAh at 3.6v = 1.1x3.6AH = 4Wh. My 18650s are rated as 2700 mAh at 3.7v = 2.7 x 3.7 = 10 Wh.

Experience says that the capacities of rechargeable batteries are optimistic, but the ratio of 2.5:1 is about right.

The other issue is the actual power drawn by the torch. The LED power figures (3.5w in this case) are absolute maximum. That's the power above which the LED fails. Permanently. Any practical device using one operates the things at a lower level. My 1100 mAh AAAs run the torch for about 1 1/4 hours before it fades, a 18650 for about 3 1/2 hours. This suggests that the LED is being run between 1/2 and 3/4 abs max power.

 

[2wd]

The weather is still pretty rubbish here so still not tried it on the bike

But I did venture out onto the street

I live at the top of a hill so have a good vantage point with not many obstructions and this light was still shining strong on houses 70+ metres away (a rough estimate)

Had to turn it off pretty quick though before I got got locked up and accused of being some sort of torch perv

 

[Svendo]

No but the arithmetic's wrong.

The AAAs are in series so a set of 1100 mAH rechargeables give 1100mAh at 3.6v = 1.1x3.6AH = 4Wh. My 18650s are rated as 2700 mAh at 3.7v = 2.7 x 3.7 = 10 Wh.

Experience says that the capacities of rechargeable batteries are optimistic, but the ratio of 2.5:1 is about right.

The other issue is the actual power drawn by the torch. The LED power figures (3.5w in this case) are absolute maximum. That's the power above which the LED fails. Permanently. Any practical device using one operates the things at a lower level. My 1100 mAh AAAs run the torch for about 1 1/4 hours before it fades, a 18650 for about 3 1/2 hours. This suggests that the LED is being run between 1/2 and 3/4 abs max power.

Ah, I see now. yes that makes perfect sense. I shall return my 'O' level physics certificate immediately!

 

[biggs682]

going to order 1 to see how good , will advise