limited production :: hand crafted :: high performance :: rechargeable :: premium flashlights

This is my blog about creating a startup LED flashlight business. I'm a designer, fabricator, and strategist and I'm passionate about making ideas real. I believe that products are about people, that they should be built to last, deliver real value, and that we need to do a better job than we have in the recent past.

Most of my career has been contract or freelance work and I've crafted products and strategies for both big international companies and startups. I also used to work in the "industry" fabricating special effects for film and TV, along with the occasional hot rod. Bottom line, I love making things.

I'm starting this blog so you can follow along, from day one, and see what it's like to start a business, or fail in the process. Only time will tell, but I hope you find this interesting enough to stay tuned, comment, link, like, tweet, and (most importantly) participate in turning this idea into something tangible and valuable.

For a good place to get started with general info about who, what, why, etc., check out the "Stickies" on the left side of the page. Thanks for stopping by and please don't hesitate to ask questions and get involved!

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Tuesday, February 22, 2011

Seth's question answered!

SethML said...

"How is this more than just some batteries, an LED, and a switch stuck in a fancy housing? Now's your chance to talk about Lithium-Ion battery charging/balancing, constant-current LED drivers, brightness modes, etc!"

In many ways these lights are exactly what you describe, and assemblage of components. However, I think these lights are unique on two levels. One, I make every one by hand. Two, there are a lot of components out there in the world and I've selected the absolute best and integrated them into an incredibly optimized, high-performance system. The only way these lights will get better is when I have enough volume to justify designing and manufacturing the components I currently buy off the shelf.

Exploded View: click the image for a super size version
I've already posted on batteries and chargers so you can navigate to those links for more info. Suffice to say battery technology has come an incredibly long way in the last five years. Modern li-ion batteries have no memory and significant energy density. If it was a car it would have both a huge gas tank and tons of horsepower.

Modern batteries are also capable of extremely high current output when compared to standard alkaline batteries. LED lights that run on alkalines (most LED lights on the market) are low output because alkaline batteries simply can't deliver the current needed to motivate a high power LED into releasing its lumens.

Even though LEDs are extremely efficient, generating this much light also generates significant amounts of heat. The configuration I've devised is about the maximum number of lumens you can get out of a light with these physical dimensions (~ 1" x 6"). If you want more power, it means you need a bigger light (thermal mass) to dissipate the heat. As LED's become more efficient it may change the equation slightly, but I doubt significantly, in the near future.

Solid (one piece) heads dissipate more heat from the LED
So, on the "high" power setting these lights get hot. You might even be inclined to say, "Woah, that's hot."  This is normal...but like I said before...we are pushing the limits of the technology. If you turn the light on high and leave it sitting on a table for 10 minutes it will get "really" hot. But if you are holding it in your hand for 10 minutes, the light will be less hot. This is because the light is actually transferring some of the heat to your body...meaning that holding the light actually helps it stay cool.

I believe my lights are constructed and engineered in such a way that you can run them on high, indefinitely, in open air, with little risk of damage. This applies to room temperature. If the ambient air is already 110F then all bets are off. If you are holding the light in your hand (and your body is absorbing some of the heat) I'm confident that they can be run indefinitely with virtually no risk of damage (at room temperature).

Like most things in life, you should use good judgement. If you think it's "too" hot then turn it off or use a lower power setting. Running on medium the light will get slightly warm and on low, no perceptible heat at all.

LED drivers have come a long way as well. Surface mount components have made it possible to stuff a ton of electronics on a little chip that is about 3/4" of an inch in diameter...flashlight size. The drivers I'm using are Constant Current (CC) linear drivers optimized for use with a single li-ion battery. The first advantage is that you get constant light output as the battery drains. With most other flashlights, as the batteries get lower so does the light output.

Heads with LED drivers installed
The drivers I'm using also have three modes of output. High, medium, and low. For more info on this you can check out the answer to Stanley's question (that's my Dad!). These modes are accessed by "pressing" on the tailcap button repeatedly. A "press" is like focusing an automatic camera...just a little bit of pressure but not a full "click." In order to lock in the selected level you just "click" the button fully. This arrangement also provides a "momentary-on" feature that can be activated without latching the light in the "fully-on" position.

The driver also has a memory function, meaning that if you leave the light in the "on" position for two seconds or more...the next time you turn the light on it will activate on the last used power setting.

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