Cheap, powerful rear light?
05-27-09 | 04:23 PM
#226
Senior Member
Joined: Mar 2004
Posts: 5,049
Likes: 11
From: La Verne CA
Bikes: Litespeed Liege, Motorola Team Issue Eddy Mercxk, Santana Noventa Tandem, Fisher Supercaliber Mtn. Bike
I personally use a PB Superflash on my seatpack but just added one of these for a little extra added visibility.. I just wrap it around my rear triangle, just above my rear brakes.. Nathan Acid Reflex Snap Band LED Light.. I also use it for running at night, just wraps around my arm.. It uses 2 small watch batteries for the leds..
https://www.pricepoint.com/detail/169...-Snap-Band.htm
https://www.pricepoint.com/detail/169...-Snap-Band.htm
05-28-09 | 05:36 AM
#227
Senior Member
Joined: Jun 2007
Posts: 12,257
Likes: 5
From: A Coffin Called Earth. or Toronto, ON
Bikes: Bianchi, Miyata, Dahon, Rossin
I've tried P7s and R2s with a few different red filters and the Ultrafire is much brighter.
There's no point it turning your front light into a rear, you don't get much light and you just have to buy another front light.....
It's worth noting that the energy of a photon is proportional to it's frequency (violet can have nearly twice the energy of red), so if you filter out everything but red you are losing more than 80% of the light and only keeping the lower energy part.
The redder the filter the more light it's stopping, so realistically you may only be allowing less than 10% of the light emitted by the P7 through.
Still......if it's a cold night you can warm your hands on it.....
There's no point it turning your front light into a rear, you don't get much light and you just have to buy another front light.....
It's worth noting that the energy of a photon is proportional to it's frequency (violet can have nearly twice the energy of red), so if you filter out everything but red you are losing more than 80% of the light and only keeping the lower energy part.
The redder the filter the more light it's stopping, so realistically you may only be allowing less than 10% of the light emitted by the P7 through.
Still......if it's a cold night you can warm your hands on it.....
most use a blue LED with phosphor coatings to produce red and green which results in a visibly white light.
the higher power violet and blue lights aren't as visible from further away due to the wave length.
green, amber and yellow are quite good for being seen.
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Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
https://sanfrancisco.ibtimes.com/arti...ger-photos.htm
Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
https://sanfrancisco.ibtimes.com/arti...ger-photos.htm
06-17-09 | 07:49 AM
#228
Fat Bottomed Fredwina
Joined: May 2009
Posts: 174
Likes: 0
From: Almost a cheesehead ;)
Bikes: 1998 Raleigh SC-200
Another for this Ultrafire. I got mine on Monday and installed it. This is blindingly bright, even in daylight. Excellent value, IMO.
How has it been holding up in wet weather for you guys?
for this Ultrafire. I got mine on Monday and installed it. This is blindingly bright, even in daylight. Excellent value, IMO. How has it been holding up in wet weather for you guys?
06-19-09 | 11:50 AM
#231
Member
Joined: Jun 2007
Posts: 27
Likes: 0
I have been running mine since Feb/March of this year in rain without any problems. portland, oregon rain, so more constant that super heavy.
If you look back at my previous post, I dropped this about 5' while moving on my bike at about 10mph with no ill effect.
FYI
If you look back at my previous post, I dropped this about 5' while moving on my bike at about 10mph with no ill effect.
FYI
