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 Post subject: Watts vs lumens
PostPosted: Wed Sep 12, 2012 12:13 pm 
retrobike rider
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I have a retro Lumicycle NiMH system with the standard 12w spot / 20w flood halogen lamps, but the battery is past its best so I now need a new system. I haven't got any experience of more modern lights, so I'd be grateful for any advice on how brightness in lumens is compared to watts. My impression is that my friend's 300 lumen Exposure helmet lamp is brighter than my 12w spot. Do you agree with that? Roughly speaking, how many lumens is equivalent to a 12w halogen spot?

Many thanks


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 Post subject:
PostPosted: Wed Sep 12, 2012 12:52 pm 
MacRetro rider
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A 300 lm lamp source should be roughly 3 times brighter than an equivalent 12w halogen lamp.

But it isn't always that simple. The huge advantage of LED is that it converts all of the energy from the battery to light. A halogen converts a hell of a lot of it to heat.


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 Post subject:
PostPosted: Wed Sep 12, 2012 1:15 pm 
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Tazio wrote:
The huge advantage of LED is that it converts all of the energy from the battery to light. A halogen converts a hell of a lot of it to heat.


LEDs dont convert all the energy to light, just alot more of it than incandescent bulbs. LED lights still produce heat, and LED technology is getting better and better year on year. So they can't be 100% efficient!!!


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 Post subject:
PostPosted: Wed Sep 12, 2012 1:29 pm 
MacModerator
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Anthony I've found this site a wonderful resource.



http://www.torchythebatteryboy.com/p/bi ... abase.html


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 Post subject:
PostPosted: Wed Sep 12, 2012 2:05 pm 
MacRetro rider
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JamesM wrote:
Tazio wrote:
The huge advantage of LED is that it converts all of the energy from the battery to light. A halogen converts a hell of a lot of it to heat.


LEDs dont convert all the energy to light, just alot more of it than incandescent bulbs. LED lights still produce heat, and LED technology is getting better and better year on year. So they can't be 100% efficient!!!


Of course you are correct. I should have said "most of"


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 Post subject:
PostPosted: Wed Sep 12, 2012 2:06 pm 
Gold Trader
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The candlepower chaps are pretty s**t hot on this stuff too, I normally go there first for anything I need to know about this stuff..

http://www.candlepowerforums.com/vb/content.php


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 Post subject:
PostPosted: Wed Sep 12, 2012 8:52 pm 
Old School Grand Master
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Location: Fircombe.
This provides some comparison between Lumi's old and new;

http://www.flickr.com/photos/lumicycle/page2/


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 Post subject:
PostPosted: Thu Sep 13, 2012 11:30 am 
retrobike rider
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suburbanreuben wrote:
This provides some comparison between Lumi's old and new;
http://www.flickr.com/photos/lumicycle/page2/

That's really interesting - the 20w Lumicycle halogen flood is slightly brighter than an 850 lumen Lumicycle LED flood, and a 12w halogen spot about the same as a 600 lumen LED flood. That contradicts both my own experience and what Tazio says. Maybe my existing 12 spot/20 flood system would still be quite bright but the batteries are even more dead than I thought.

This does surprise me, but if it's true it would also contradict the general perception that there have been huge advances in lights - advances yes, but how huge? My Lumicycle originally gave over 4 hours burn time on the 12w spot and weighs 800g. An equivalent genuine 600 lumen Chinese LED (say claiming 900?) that lasted 4 hours would weigh less, but still quite a bit.


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 Post subject:
PostPosted: Thu Sep 13, 2012 11:36 am 
retrobike rider
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kaiser wrote:
Anthony I've found this site a wonderful resource.

http://www.torchythebatteryboy.com/p/bi ... abase.html

That's a really good site, isn't it? It seems lots of people on here really rate Magicshine lights, but he totally pans them as very unreliable and prone to overheating.

But then the Fluxient lights that he rates more highly, he sells them himself. On one level it sounds suspicious, but maybe he genuinely sells Fluxient because he tested them and found they were good. Also a two year warranty does seem quite confident.


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 Post subject:
PostPosted: Thu Sep 13, 2012 12:07 pm 
Old School Grand Master
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Did you see the previous page Anthony?

http://www.flickr.com/photos/lumicycle/


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