Instructables

Rechargable LED Headlamp

First Instructable :)

I am a Caver. I love to run around underground. I also like to tinker with LED's (mainly inspired by Dan's instructable Ultimate Night Vision Headlamp

This is the third headlamp i have created, and the first i think might be worthy to post

Oh yeah a description, This is a LED headlamp made with 3 3.7V lithium batteries and 2 ~4 watt Cree Q5 LED's. The led is driven by the same device as Dan's headlamp, a 3021 BuckPuck from luxdrive.
 
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Step 1: Supplies!

Picture of Supplies!
Gather your supplies.

I bought/gathered my stuff from a few differant places

DealExtreme.com
- 2x Cree Q5 LED
- 2x Reflector
- 6x 18650 Lithium batteries ( they come in packs of 2, so i got 6 total)

Radio Shack (some capitol purchases here.)
- Mini Tool Set
- Soldering gun
- Wire
- 9-volt battery leads
- 3" x 2" x 1" project enclosure

LedSupply.com
- 3021 BuckPuck driver (the 1A version)

My Dad's Shop
- Curly cable from a cell phone car charger
- ~2 inch Aluminum heat sink
- Thermal Grease
- cheep headlamp strap
- Curly cable ( i got mine from an old cell phone charger )

Step 2: Testing

Picture of Testing
This round actually matters. How bright do you want your light to be? how many settings? what kind of batteries, how many? so i got out my old breadboard and played around for a while.

I got a set of reed switches to play with (they are really cool), but ended up going with a double pull double throw switch from radio shack.
Mike Nelson (author) 5 years ago
@dan They are built in to the batteries, the ones that shut them off if they get below a certain voltage? (these drop off at about 2.5 V.) cool thing is if lithiums don't work out, i already have a 6x AAA setup that plugs into a 9V slot, and i can setup a 6x AAA one just as easily. it also runs off of a single 9V, but I'm guessing not much more than an hour or two on dim... those things can't hold too much. @ahicks As far as a fuse, I'm only drawing 1A out of it, do i really need one?
Yes you still need a fuse! It's in case you accidently short the things. Otherwise they have a nasty habit of going BANG and then catching on fire!

As for the Low Voltage Cutoff (LVC) circuit that Dan mentions, the 2.5V in your batteries is a bit low and might shorten the life of the cells. However, luckily it looks from your description that the light might cut off by itself before that which is great! Just watch though that you don't leave it on once it's cut out just in case the buckpuck still tries to suck some small current out which drains the cells.

Looks good though...nice instructable.
rondos4 years ago
not a good idea to solder batteries, look for a holder. think personal safety. nice instructable.
Sandisk1duo5 years ago
Great instructable!
Mike Nelson (author) 5 years ago
After running the light for a 4 hour session on DIM and a 3 hour session on dim (both on the same charge) the battery has dropped from 12.6V to 11.9V. would i be correct in assuming:

.1V drop per hour
minimum voltage needed: 7.4(lights) + 2(driver) = 9.4V
life span on dim = 12.6 - 9.4 = 3.2 / .1/hour = 32 hours?

makes me really excited to see how long it will last on high :)

any more comments will be greatly appreciated.
Cool! Great Instructable! Thanks Joe
Standard cell phone batts won't work, or for long, they can't handle the current draw. Look into some R/C batteries. Some nice, small Li cells w/ built in protection circuits can be found. Price depends on how much capacity you want. j
dan5 years ago
nice write-up and build, but you need a lithium protector circuit if you use lithium batteries. they only last a couple of charges otherwise. the protectors have become really cheap and easy to use:
http://www.all-battery.com/index.asp?PageAction=VIEWCATS&Category=178
ahicks5 years ago
Nice instructions. Good job! One question: where's the fuse? Shorting Li cells can be very bad!
LinuxH4x0r5 years ago
Very good job! I might do something similar, but I would use standard cell phone batteries.
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