I'm in an adventure race at the end of this month and am stocking up on required items. I've spent plenty and would like to just make it thru the bike section cheaply. MEC has an LED 1-watt bike light for $11.50 cdn. I know one won't be enough, so I'm planning on mounting 4 of them on the handlebar. I have a 1-watt headlamp also. This gives me lots of redundancy in case a crash takes out a light or two.

Here's the light in question:
http://www.mec.ca/Products/product_detail.jsp;jsessionid=GKZtqxQ4mJ16zVDgNyBdRRLp5nQcn1dNlhjV2j8htlhtrxGCNk1q!728726988?FOLDER% 3C%3Efolder_id=2534374302692895&PRODUCT%3C%3Eprd_id=845524442621577&bmUID=1187682669370

Here's a tinyurl which will work for a week or so:
http://preview.tinyurl.com/yop4bd

I'd like some feedback on whether my idea is sound at all. Or just stupid. The race starts at 4 and if we bike first, i'll need a max of 3 1/2 hours of light. Time-wise, they are fine for sure. Lumens-wise, beats me. Other than reflector quality, does four 1-watters equal one 4-watter? Given same type of LED of course.

The race is advertised as "easy atv type trails". Shouldn't be too technical and if it is, I can always walk.
thanks for your suggestions...thehick

Those are for a race? I'd get something better if speed is of the essence.

Actually, you'll have better lighting with the 4 1watt lights vs. 1 4watt light given the battery configurations. To use a 4 watt bulb with 4 AAA batteries will not give as good a light, nor for as long...although, 3.5 hours for an LED is nothing. If you aim them the way you want, you should have plenty of light for a ride with 4 combined 1watt lights.

does four 1-watters equal one 4-watter? Given same type of LED of course.


The simple answer is "YES".

Now standby - I'm going to get technical on you. If that is an "I Don't Care" to you then please skip over this post.

A Watt is a measure of electrical power. By definition Power = Volts x Amperes.

The Volts in the case of a battery powered light is determined by the type and number of cells used. Your provided info stated the light uses 4 AAA batteries but doesn't state the type i.e. alkaline, NiMH etc. Most have a voltage that is similar enough for this application but they are NOT the same! And the voltage of cell does not remain constant with use. After a fresh charge (if rechargable) the voltage will be at or near its highest value and thereafter during use or even while sitting idle, the voltage decreases as time passes. Therefore the Watts (power) will decrease during use.

If you supply the same voltage to four identical LEDs they will be consuming four times the number of Watts as one by itself will consume. Hense ' The simple answer is "YES" '.

The Amperage in the formula above is determined by two thing. The Voltage applied and the characteristics of the LEDs. Even "Given same type of LED of course" there will be some variation in the LED properties so likely each will draw slightly different current (Amperage). Those differences will probably be small enough to ignore i.e. are insignificant. A bigger factor in the overall performance could be the variation in LED efficiency of converting the current flowing through it into light (Lumens). In my experience there can be a significant variation in the visible light output from a LED even when taking a bunch of the same 'make and model' of LEDs.

All that to say Yes. Four 1-Watt lights equals one 4-Watt light. But they may not be of equal brightness due to variation in battery and LED characteristics.

So "GO FOR IT!

Lets see
A 3v led draws 333mA to burn 1watt.
2x AAA =3v, and guestimating 1000mAh capacity they will power the led for 3 hours.
So 4 AAAs should run 6 hours at 1watt. This light goes for 4 times that(24hrs) and Im being generous with the math and assuming no losses (should be more like 3.3v and probably 1000mAH is generous too).

It probably does have a 1w LED in it but its not running at 1w...more like 0.2watts
(I have a 1w led head torch that gets 20hrs out of two button cells. Amazing.)

So in this case you will need 20 of these to equal a 4watt light.


You will need wider handlebars.

My personal favorite is the Mag-Lite 2 AA 3-watt LED flashlight. It's bright enough to actually see where you're going and the adjustable head allow you to adjust the beam pattern to your liking. Some Wal-mart stores are clearing them out at $19. You get 2.5 hours of burn time on 2 alkaline AA batteries but if you purchase AA lithium camera batteries you can get about 7 hours of burn time. Make sure to get the disposable 1.5-volt camera batteries and not the 1.2-volt rechargeable batteries as those will not work properly in the Mag-Lite flashlight.

If you can use a soldering iron you can make an external battery pack for your choice of flashlights. Here is a photo of my Mag-Lite with a DIY external battery adaptor taking the place of internal batteries.
http://i143.photobucket.com/albums/r154/n4zou/mounted.jpg

http://i143.photobucket.com/albums/r154/n4zou/batteryadaptor.jpg

This allows connecting two C or D batteries greatly increasing the burn time on standard alkaline batteries.

I am currently designing and testing a hybrid lighting system consisting of a Mag-Lite 2 AA 3-watt LED flashlight, Bottle dynamo, LM 317 voltage regulator power supply, and 2 ni-mh rechargeable batteries. A typical bottle dynamo normally powers two bulbs with a total of 3-watts or 500 mA. Testing shows the Mag-Lite draws about 400 mA and my tiny LED tail light draws another 20 mA. This provides a charging current of 80 mA for the ni-mh batteries. The two ni-mh batteries will power the flashlight and taillight for about 15 minutes when fully charged. In actual operation 15 minutes is more than enough time when stopped for stop signs and red lights when the dynamo is not powering the lights and charging the batteries.
http://i143.photobucket.com/albums/r154/n4zou/prototype.jpg

Want to go cheap yet get a lot of light? If you have a Sam's Club nearby, check out the Element 3w flashlight two pack for $29. Compact, little lights that run on 3AAA cells. They use Luxeon III emitters, and are good for 70-80 lumens each. The pattern is fairly tight, but much much broader than the typical flashlight 'hotspot'. I'd say that one of these compares very favorably with my old 5 watt rated Specialized Astro 5 halogen in both total output and beam spread.

http://www.samsclub.com/shopping/navigate.do?dest=5&item=341405

I bought an extra two pack for experimentation. Using just the STAR (heatsinked) emitter and the optics package (reflector, lens and head shell), I am planning on mounting two of these puppies in an old Bell 'wide reflector' handlebar bike light. Wire this combined head to an external battery pack. That will give me easy bar mounting and removal using the quick connect. Total investment in the light assembly will be around $40, plus the external battery pack.

Or just simply use these two flashlights as is and bracket mount them to your bars. I still think this will be far superior to your suggested 4 x 1watt units.

The calculations you've done are a real eye-opener. None-the-less I have picked up 2 of these lamps and will give them a test and post the results. All I want is to be able to ride trails at night at a fairly slow speed. We'll see.
thanks...thehick

I had some time on my hands so I put together the HomeDepot light as described very well at:
http://bike-recumbent.com/headlight.shtml

Here's an image with 1 X 1-watt LED (TopLeft), 2 X 1-watt LED (TopRight) and one with the 20-watt MR16 Halogen on overpowering the other two completely.

I'll be testing on the trails Monday morning. Yep. Before dawn.
...thehick

You 15W light is roughly equivalent to that 4W of led light you were wanting(using the latest tech).

I still think you should go by another 18 of those led lights and some wider handlebars to mount them on, just to see if I was right about needing 20. :D

I am trying to get by for a race in 2 weeks. I intend to build a home-made Luxeon III based system later on thru the winter. The parts are a little dear here in Canada. But, yes, it is the future. For now, cheap halogen based lamps with led for backup is my only option. Wider handlebars are a bit touchy. As it is, I can barely fit thru some of the tree-lined trails. I am thinking off chopping an inch off each side.
...thehick

Hmm.. 4xAAA eh? Better see if you can get a rapid charger to charge up spare cells. A pack of alkalines can save you time if your cells are low on power just load up and lock and rock and roll. Not sure if they sell speed loaders (spare battery holders) for those if so then you can swap out fast hopefully before the guy 5-10sec behind you passes you.

I just noticed this (http://www.mec.ca/Products/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524441878991&FOLDER%3C%3Efolder_id=2534374302692895&bmUID=1189411047784) unit is on sale. $139 to $89. Also this (http://www.mec.ca/Products/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524442420135&FOLDER%3C%3Efolder_id=2534374302692895&bmUID=1189411047783) unit is on sale for $165 to $119.

Sorry to deviate from your original topic question. I would go with 4 x 1 for a wider spread of light but you lose on the speed side of things as your light throw range is cut down short. I guess it all depends on the race type and the terrain. If technical wider is better. If road throw is better. If half and half terrain then best to get a mix of both or else you'll probably be slower on the road side of things but make up for it on the technical side with the wide light.

You should look at the NiteHawk AL-X that runs off 4xAA for cheap and use some of those 1W so you can mix it up. The AL-X is a smooth spot but it will throw a punch in the darkness downrange about ~15 meters in front for IDing things, detection up to ~25-30 meters for reflective, optimium use of light 5 meters road/ 7-9meters trails. I own this light. You can also go to http://www.batteryspace.com and buy the NiteHawk plug and go to any RadioShack and get a 4xAA battery holder and solder or e-tape the wires together and you'll have a quick hot swap battery pack. The light is not regulated so it will wane in light.

I don't think the MEC 1W Sharks are regulated. I have a friend with it I'll ask them but they are about 20mins ride from work so I don't think thier cells are drained enough to give a runtime data yet.

You should look at the NiteHawk AL-X that runs off 4xAA for cheap and use some of those 1W so you can mix it up. The AL-X is a smooth spot but it will throw a punch in the darkness downrange about ~15 meters in front for IDing things, detection up to ~25-30 meters for reflective, optimium use of light 5 meters road/ 7-9meters trails. I own this light. You can also go to http://www.batteryspace.com and buy the NiteHawk plug and go to any RadioShack and get a 4xAA battery holder and solder or e-tape the wires together and you'll have a quick hot swap battery pack. The light is not regulated so it will wane in light.


I disagree. I also owned the AL-X, this unit is nearly worthless everywhere. Under lighted streets it doesn't throw out enough power to reveal the road to any confident degree. In total darkness situations, it similarily doesn't give out enough light to ride in confidence.

This is on-road, 20-30kph riding even. If you're doing trails or MTB, it maybe enough for you but for a 1w LED system, the AL-X even at just above cost is a total ripoff ($80 taxes in retail price at MEC).

Excuse the 10 day bump, but I really think this needed to be said.

Cree LED Fenix: will toast the 4Watt

I disagree. I also owned the AL-X, this unit is nearly worthless everywhere. Under lighted streets it doesn't throw out enough power to reveal the road to any confident degree. In total darkness situations, it similarily doesn't give out enough light to ride in confidence.

This is on-road, 20-30kph riding even. If you're doing trails or MTB, it maybe enough for you but for a 1w LED system, the AL-X even at just above cost is a total ripoff ($80 taxes in retail price at MEC).

Excuse the 10 day bump, but I really think this needed to be said.

Yeah, it is such a rip. I couldn't believe it at first. A single $20 Cree flashlight will smoke a $179.99 "K2" set-up from MEC. I ran into a guy buying one yesterday. I didn't want to interrupt him.

Maybe I should have.