I was about to place a small order from All Electronics, a great miscellaneous parts and surplus electronics shop, when I checked the front page to see if there was anything new to consider. And that’s where I saw a familiar-looking LED worklight lamp head.
I recognized these as from Dewalt DCL040 LED flashlights ($49 via Amazon).
Advertisement
Here’s their product description:
This good looking fixture is a great beginning for a shelf or display lighting project. Bright, white 1 Watt LED enclosed in a rugged black and yellow hard plastic housing with a conical reflector and a clear plastic front lens. Overall dimensions, 2.16″ diameter x 3.45″ long. Two 4″ wire leads. Operates on 3 Vdc @ 300 mA. For higher voltages use a dropping resistor (see image to left).
The price is $2.50 each, or $2.25 each if you buy 10 or more.
Buy Now(via All Electronics)
These are powered off of 3V (I tested one – it works), and you can use a higher voltage source if you choose an appropriate resistor. There’s a handy chart on the All Electronics website if you’re not familiar with powering LEDs and don’t want to head to Google for answers.
If I wanted to use a 5V power supply, I’d need a 6.67 Ohm resistance. I’d have an easier chance looking for a standard-valued 6.8 Ohm resistor. The power dissipated across the resistor will be 2V x 0.3A = 0.6W, so I’d need a 1W resistor. Or 3/4W, but I assume there’s greater selection of 1W resistors.
(I say I and not you because I’m just thinking aloud here. You’re on your own in determining a safe and reliable way to power these LED modules. I have only tested these lights at 3V, and briefly at that. I’ve got more work to do. Use any of this at your own risk.)
If I wanted to use a 6V power supply, I’d need a 10 Ohm resistance or slightly greater. Again, I’d need a 1W resistor. Maybe 12 Ohms?
1W resistors are fairly easy to find. A quick search on Mouser turned up a couple of options. 6.8 Ohm with 1W power rating and 5% tolerance sells for as low as 10 cents each, individually.
This one, from TE, is 3.1 cents each if you buy 100.
Maybe Amazon, Ebay, or a straight-from-China marketplace would be a good place to look for just a couple resistors. There’s also this Joe Knows Electronics 1W resistor kit for $35, but that’s overkill. I ordinarily use 1/4W or 1/2W resistors and would be hesitant to buy a 1W assortment for myself.
I order from Mouser regularly and will likely spend $10 on a few 1W resistors with my next order.
There are higher rated resistors too, obviously at higher cost.
But if using higher voltage supplies, maybe a voltage regulator is the way to go. Maybe I’d try for a 3.3V voltage regulator, perhaps with a small resistor to drop the voltage to 3V? A 0.3V drop at 0.3A would be what, 90 mW, so a 1/4W resistor would be more than enough.
Ben – your thoughts? How would you power these LEDs from a DC battery source?
I might dig up a fully assembled Dewalt LED flashlight and see what they use to drop the voltage from 20V Max (18V) to 3V.
I knew I wanted a couple, so what the heck, I ordered 10.
They’re a little dirty, with flecks of black (plastic?) stuck on, but they seem easy to clean. They feel a little greasy too. One wire has some fixturing epoxy stuck to it.
Anyone know what that white hot-glue-like fixturing stuff is called?
In other words, it seems that these were removed from assembled work lights. Some of the lenses are scratched a little, but aside from the slight amount of dirt, these look new.
So I’m going to assume they were removed from new equipment.
I’m not quite sure what I’ll do with 10 of them. Some will go to an LED worklight light bar project. Maybe I’ll swap the white LEDs in a few for RGB LEDs.
The output is quite center-concentrated. The deep reflector is a good one, but the output is a little harsh.
I definitely got my money’s worth, but I just have to now find a good way to use them.
Ideas?
At $2.50 each, who else is buying a few?
Oh, and if you do order one and take it apart, I’d appreciate any advice! The yellow housing screws together in one place, but I can’t see an easy way to remove the LED emitter, reflector, and lens assembly – the black part.
I wonder how and why these ended up at a surplus electronics parts store. Maybe something was off-spec. The LEDs? The housings? I doubt anyone at Dewalt will tell me, and All Electronics might not know.
Sideshow Bill says
Mar 14, 2017 at 11:16 amThe hot glue can be either polypropylene/polyethylene, or less likely, a polyester resin. If they were really spending money, it’d be a reactive polyurethane.
Mr. Creek says
Mar 14, 2017 at 11:20 amAny chance the circuitry was stripped from the light and is also for sale under a different name?
Stuart says
Mar 14, 2017 at 4:46 pmDoubtful. I didn’t spot it at All Electronics. It’s also a bit too specialty to be of much use to anyone. Some of the electronics might have battery hand-shake programming.
James C says
Mar 14, 2017 at 11:32 amDon’t use a resistor. Do a little more research, spend slightly more, and get an appropriate current or PWM-controlled driver circuit for whatever input voltage you’ll provide. It will be more efficient and you can have multiple output modes, if you’d like.
If you could find a driver that takes 20v input it would be an awesome project to 3D print a DeWalt (or another brand) battery connector / housing and essentially make your own complete flashlight.
Stuart says
Mar 14, 2017 at 5:09 pmGood points.
I’ve used PWM to control servos and know that there are PWM LED controllers, but it’s outside my immediate familiarity.
My intent was to get people started on the right path.
Here’s a PWM controller that can be connected to a microcontroller or variable 0 to 2.5V voltage source for brightness control:
https://www.sparkfun.com/products/13716
And a 3-LED driver: https://www.sparkfun.com/products/13705
They can handle 330mA per channel (I’m seeing disagreeing specs, but both are greater than the 300mA for the LEDs we’re talking about).
BonPacific says
Mar 14, 2017 at 12:01 pmI’d probably wire these up for USB (5v) power. That way you have plenty of options. You could run a bunch off a good USB wall-plug, or off a portable power bank… Or off a regular 18V battery with one of those USB adapters.
Stuart says
Mar 14, 2017 at 5:32 pmThanks, something to think about!
julian says
Mar 14, 2017 at 12:26 pmshould be able to hook them up to a (2) AA battery holder with a simple switch, right?
Great for a drill press or bandsaw task light…
JT
Stuart says
Mar 14, 2017 at 5:31 pmYes, but I don’t think that alkaline batteries won’t last for very long.
Lithium cells would do better.
I’d ordinarily recommend rechargeables, but the voltage is lower. I just tested the light module with 2-cell holders and with rechargeables the light is much paler.
Rechargeables output 1.2V each, and 2.4V is just too far below 3V. You get some light, but it’s not worth it.
If using rechargeables, I’d use a 3-cell holder and appropriate resistor to take the voltage down to 3V.
It’s REALLY bright, though, and way too focused for close-up use. I think it’d be too glarey for an on-tool light.
Wayne says
Mar 14, 2017 at 6:38 pmMaybe rough up the lens surface to diffuse that beam?
Stuart says
Mar 14, 2017 at 7:19 pmIt’s got a very deep reflector. Modifying the lens into a diffuser will have minimal effect. It might help a little, but you’re still going to get that very bright center spot.
Jason says
Mar 14, 2017 at 12:42 pmI wonder what the lights were stripped apart for the crazy LED lights the Amish use
fred says
Mar 14, 2017 at 1:21 pmWould wiring two of them in series off a 6V power supply work?
Stuart says
Mar 14, 2017 at 5:45 pmIt should.
MT_Noob says
Mar 14, 2017 at 1:54 pmIs is silastic?
Stuart says
Mar 14, 2017 at 5:47 pmNot sure. It’s opaque white and hard.
Bill says
Mar 14, 2017 at 2:42 pmThis looks to be an intriguing possibility. I however, have been wanting to convert a floor lamp, which I love the design of, to LED. But I don’t want to simply install an LED bulb and one reason is that this lamp has a 3-way switch. What I really want to do is replace the lamp socket and switch with an LED chip or chips mounted to a pcb along with a touch switch. The floor lamp is the type that points to the ceiling and with the right LED setup I should be able to do this. It may need a diffuser plate set above the LED. Does anyone know of a good source of materials to accomplish this?
Bob S says
Mar 15, 2017 at 10:43 amYou could buy a 3 way LED (30/60/100 watt equivalent) for your lamp. They are $14.97 at Home Depot. I installed a couple of them in 3 way sockets for my living room. I have been pleased with them.
Farid says
Mar 14, 2017 at 4:33 pmStewart,
Ready made drivers are probably the easiest. Try this driver: 10-40VDC input 350mA 2-38V out constant current.
http://www.digikey.com/product-detail/en/triad-magnetics/TLM4036DC-0350/237-1319-ND/1127381
There are others that you can power from ac as well with which you can probably combine series and parallel LEDs for best cost efficiency. Check this search list:
http://www.digikey.com/products/en?FV=fff40009,fff804be&k=led%20driver
If you want to roll your own, there are tons of ICs. Not the most efficient but easy enough is to use an adjustable regulator in constant current mode. LM317 comes to mind.
Stuart says
Mar 14, 2017 at 5:50 pmAn LM317 certainly looks like another good option.
Ready-made drivers are an option, but it comes down to cost. $17 for the one you linked to, plus materials to make it all work?
My aim is to keep things cheap.
jsbson says
Mar 14, 2017 at 6:38 pmIf you search Aliexpress or ebay for “cc/cv DC-DC power supply” you will find many that would work for wide range DC input one watt led driver. There are also smaller and less expensive ones that are used inside many MR11,MR16 LED replacement bulbs but they are not very flexible. Amazon has them as well but typ. 5X the price.
https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=LM2596+LED+Driver+DC-DC+Step-down+Adjustable+CC%2FCV+Power+Supply+Module
Farid says
Mar 17, 2017 at 9:35 amYep, Ali express has a bunch, and so does flea-bay. Alltronics has an adjustable switching supply for under $8 . Although not consonant current, you can use a low value resistor in series and adjust the voltage out close enough to get you what you need to run off a 20V battery.
If you do go the LM317 route, just keep in mind that the more LEDs you add in series and closer you get to the battery voltage ( allowing for some regulator headroom), the more efficiency you get, otherwise, you’ll get a lot of energy dissipated across the linear regulator as heat. You probably already know this but I’d thought Id mention it.
Also, LED lights need to be driven with constant current for consistant light output, otherwise the light will continue to dim and color will shift as the battery voltage drops if using a simple resistor circuit.
Farid says
Mar 17, 2017 at 10:03 amYou can use a 555 timer as PWM driver and pass thru transistor as well or even a transistor oscillator, but anymore for the cost, using one of the dedicated ICs and and handful pf parts is just as cheap. The only issue is most new ICs are surface mount. I personally try to stick with SOT-23 or SO-8 packages as they are still manageable if I need to tack them on a proto-board.
For the more DIY die hard, companies like TI, Linear tech, etc have online power design tools that help out with part selection and design simulation. I was just using some last week for a new design. If you have the time, you can create switcher regulators for this purpose for around $2-3 each.
One of the simplest ICs to use is Diodes Inc. AL8861 (it only needs one each external diode, capacitor and resistor)
I was able to squeeze a point-to-point soldered Zetex ZXLD1350 (alternate is ZXLD1356) into the battery case of an LED book reading-light and transformed it from a plain battery driven LED to a high efficiency light, thus tripling the battery life. The circuit is simple enough you can cut traces into a PCB using X-acto knife. There are many more examples out there.
Andrew says
Mar 17, 2017 at 8:58 ami would go for an LM7803 or equivalent. such as this https://www.sparkfun.com/products/526
Mr. X says
Mar 14, 2017 at 7:48 pmLooks like it would be easy to fabricate a mount and put a few on a snowblower for better nighttime use.
Chris
Stuart says
Mar 14, 2017 at 10:18 pmI considered that, inspired by the Ego I’ve been testing that has built-in lights (that eventually get covered in snow), although modifying cheap flashlights might be easier. Even if fabricating a weatherproof mount was easy, the modules are not weather sealed.
Joe Hanson says
Mar 14, 2017 at 8:32 pmCould you make one of these run off of a 12V car battery and put a few things together to make a worklight you can leave in your engine bay of your car or truck? I remeber seeing some old trucks had a worklight on a spool that stayed in the engine bay and readily available. Maybe attach a magnet to a swiveling base. Could be a fun little project.
Stuart says
Mar 14, 2017 at 10:21 pmI don’t see why not.
Magnet base + custom frame to replicate the pivoting capability, some electronics including an efficient way to drop the voltage, long wire, and you’ve got it.
casey says
Mar 14, 2017 at 11:46 pmhow would 4 do wired together on a 12v-14v car battery?
Stuart says
Mar 15, 2017 at 12:25 amDon’t know, and to be honest it’s not something I would try. I’d be more inclined to drop the voltage, as car battery voltages can vary, even above 14V.
Jeremy Brown says
Mar 16, 2017 at 1:30 amBest thing I ever did too my dewalt light that used the same led and lens was to glue some dotted translucent Ikea drawer liner I cut in a circle to fit. Diffises the light nicely without distorting the beam too much.
Bill K says
Mar 16, 2017 at 10:04 amHow about putting 4 lights in series and use a 12v supply?
Eric says
Feb 22, 2018 at 5:00 pmOr 6 for 18v? I have been playing around with some of the cheap 3w multi-bulb housings from Amazon and I have been seriously impressed for the price. Most of them claim to run well from 18v and they have not minded being hooked up to tool batteries at all. I got a multipack of the lipo battery alarms and made a harness with a low-voltage warning.
Paul says
Mar 16, 2017 at 3:28 pmAbout 2-3 years ago I made a trip down to Kiem Lumber (Ohio):
http://www.keimlumber.com/
They have a lot of tools there and lets just say that not everything was stock OEM. Two things that I remember are that some of the Bosch Dual Glide miter saws (both 10 and 12″) were modified with a different motor and that on a “junk” or rather “Christmas sales” table were some of the DeWalt flashlights that belong with those heads missing. Instead, they had a standard threaded light bulb socket wired into its place. I found where your lights came from.