milkyspit
Flashlight Enthusiast
Pimped-Out Makita 18V Work Light!
At PF6 a longtime friend, MSaxatilus, asked if I might be interested in taking on an unusual modding project: doing an LED conversion on his new Makita 18V Li-ion worklight. Given my many obligations as of late... job search, family time, paying down bills, doctor and dentist appointments, college reunion... how could I resist!
Anyway, let it be said that the Makita 18V worklight is a nice light even in stock form. It pumps out a surprisingly clean hotwire beam... using a smooth reflector, no less! It's nice and bright, runs for roughly 5 hours, sports a shock-resistant bulb filament (or so I am told by the hotwire demigods), and feels good in the hand. It's got that nice heft that's indicative of a good build quality. Head swivels to multiple positions without so much as a flicker. The darned thing even has a tactical clicky!
The stock light. Darned nice!
Well, scavenger that I am, first thing I did was arrange to keep the reflector and bulbs, just in case I find a good use for them in the future, heh heh. :naughty:
Now what to do? After giving it some thought, it came to me! Install a pile of garbage and pawn it off as a mod, and pocket the moolah$$! Er, I MEAN, recycle some idle components into a compelling package for MSax.
Makita degutted!
The centerpiece of this mod is an old Pentium CPU heatsink. To make the thing fit, I had to Dremel off on end (it used to be rectangular)... also Dremel off the fins at the four corners... then fit the sink around the bulb post by removing four pins in the center. To remove those four I used a hardened steel bit that looks a bit like a miniature Medieval spiked club, and is intended for cutting ceramic tile... figured if the thing's hard enough for tile, it ought to do the job on aluminum! And so it did... I used the "timbeeerrrrrrrr!" strategy of cutting notches into the lower portions of the pins, then wiggling them back and forth until they broke free... think chopping down trees in the forest and you'll understand!
I generally like the concept of a press fit to the components in that it's easier to build initially, and easier to fix should something go wrong. At the same time I don't want the light to fall to pieces under normal use! The solution here was to squeeze springs around the heatsink fins more-or-less at the four corners, so they'd press the entire assembly upward, against the plastic lens of the light. Pressure was actually far greater than expected! But it does seem to hold without damaging things, so guess it'll be okay.
The output is now regulated via a simple linear regulation circuit... more on that later.
Heatsink with spring assembly... this side goes INTO the head.
Side view of the assembly... also visible is the LS array and bulb post hookup.
The flanged bulb base pictured above came from an instaflashed Mag bulb (I think)... it sits in the bulb post for power hookup, with the added advantage that it's a non-destructive mod... MSax could mount a regular bulb in there again at a later date if he wishes. The disadvantage, not so much the mod's fault as a design shortcoming of the stock light itself, is that there's no retaining sleeve or tab on the bulb socket. This will be the weak point of the mod... at some point the base might wiggle itself enough out of the socket to disconnect power from the circuit... I've warned MSax of this and he's comfortable with the prospect of opening the head to reseat the bulb base if needed. Hopefully it won't happen though!
Closer look at the bulb hookup.
The circuit takes advantage of the high input voltage (18V nominally) by using a simple LM317 linear regulation chip in constant current configuration. As designed, the LM317, sense resistor (a really HEAVY DUTY PAIR of them!), and four LuxIII's are in series. The circuit sends 250mA constant current through all four emitters. The LM317 isn't exactly the pinnacle of efficiency, and yet it's a good, heavy duty workhorse of a chip... gets added protection by being heatsinked to the, er, heatsink! Assuming a loss of 3V at the LM317 and sense resistor... probably a reasonable estimate... that implies better than 83% efficiency... IMHO not too shabby! :naughty:
As for the emitters themselves: they're very warm white-tinted LuxIII stars substantially underdriven to allow for extremely long runtimes without too much concern for heat buildup. The four stars are super glued together in the shape of a diamond, with copper braid and heavy gauge wire connecting the circuit. The entire array sits on the heatsink, not glued, not even slathered in thermal goop... it sits DRY on the heatsink! Well, not quite... one fringe benefit of this Pentium CPU sink was that it already had a thermal pad mounted on it... the four stars all sit on at least good chunks of that pad, and are held tightly in place from the upward spring pressure of the heatsink assembly beneath.
For those interested, the bins of the four stars are: SX1J, SX1J, SX1J, and SX1K.
LuxIII array.
Time to close 'er up! To my horror, the first time I closed the bezel the thing didn't light. Fortunately, opening the bezel and reseating the heatsink seems to have cured things, and it continues to work even after shipment to MSaxatilus, or so he reports.
:sweating:
Bezel closed.
Time for a test run! This wasn't designed to be a particularly pretty mod, and yet there's a certain beauty to the thing in an industrial sense... plus when lit, one gets a feeling of power, heh heh... :naughty:
Applying the juice!
So how does it work? Does it meet the intended mission? Well, sort of. I'd purposefully used 17mm reflectors in an attempt at more sidespill and less throw, but despite my best intentions the darned thing still manages to pump out one heck of a hotspot!oo: Actually, I found myself carrying this light around house and yard for a day or two afterward, before sending back to MSax. It's one of those rare lights that actually exceeds a modder's expectations. I was shocked at just how useful the thing was! Based on a quick phone chat, Dave (MSaxatilus) seems to agree. It's a keeper!
The obligatory ceiling shot. Note the broad sidespill, and yet with a pronounced hotspot!
(Each ceiling board measures approx. 1.5 inches across, and the light was roughly 1 meter from the ceiling.)
Did I mention the circuit should run 10-12 hours in full regulation?oo:
Thanks for reading, folks! :bow:
At PF6 a longtime friend, MSaxatilus, asked if I might be interested in taking on an unusual modding project: doing an LED conversion on his new Makita 18V Li-ion worklight. Given my many obligations as of late... job search, family time, paying down bills, doctor and dentist appointments, college reunion... how could I resist!
Anyway, let it be said that the Makita 18V worklight is a nice light even in stock form. It pumps out a surprisingly clean hotwire beam... using a smooth reflector, no less! It's nice and bright, runs for roughly 5 hours, sports a shock-resistant bulb filament (or so I am told by the hotwire demigods), and feels good in the hand. It's got that nice heft that's indicative of a good build quality. Head swivels to multiple positions without so much as a flicker. The darned thing even has a tactical clicky!
The stock light. Darned nice!
Well, scavenger that I am, first thing I did was arrange to keep the reflector and bulbs, just in case I find a good use for them in the future, heh heh. :naughty:
Now what to do? After giving it some thought, it came to me! Install a pile of garbage and pawn it off as a mod, and pocket the moolah$$! Er, I MEAN, recycle some idle components into a compelling package for MSax.
Makita degutted!
The centerpiece of this mod is an old Pentium CPU heatsink. To make the thing fit, I had to Dremel off on end (it used to be rectangular)... also Dremel off the fins at the four corners... then fit the sink around the bulb post by removing four pins in the center. To remove those four I used a hardened steel bit that looks a bit like a miniature Medieval spiked club, and is intended for cutting ceramic tile... figured if the thing's hard enough for tile, it ought to do the job on aluminum! And so it did... I used the "timbeeerrrrrrrr!" strategy of cutting notches into the lower portions of the pins, then wiggling them back and forth until they broke free... think chopping down trees in the forest and you'll understand!
I generally like the concept of a press fit to the components in that it's easier to build initially, and easier to fix should something go wrong. At the same time I don't want the light to fall to pieces under normal use! The solution here was to squeeze springs around the heatsink fins more-or-less at the four corners, so they'd press the entire assembly upward, against the plastic lens of the light. Pressure was actually far greater than expected! But it does seem to hold without damaging things, so guess it'll be okay.
The output is now regulated via a simple linear regulation circuit... more on that later.
Heatsink with spring assembly... this side goes INTO the head.
Side view of the assembly... also visible is the LS array and bulb post hookup.
The flanged bulb base pictured above came from an instaflashed Mag bulb (I think)... it sits in the bulb post for power hookup, with the added advantage that it's a non-destructive mod... MSax could mount a regular bulb in there again at a later date if he wishes. The disadvantage, not so much the mod's fault as a design shortcoming of the stock light itself, is that there's no retaining sleeve or tab on the bulb socket. This will be the weak point of the mod... at some point the base might wiggle itself enough out of the socket to disconnect power from the circuit... I've warned MSax of this and he's comfortable with the prospect of opening the head to reseat the bulb base if needed. Hopefully it won't happen though!
Closer look at the bulb hookup.
The circuit takes advantage of the high input voltage (18V nominally) by using a simple LM317 linear regulation chip in constant current configuration. As designed, the LM317, sense resistor (a really HEAVY DUTY PAIR of them!), and four LuxIII's are in series. The circuit sends 250mA constant current through all four emitters. The LM317 isn't exactly the pinnacle of efficiency, and yet it's a good, heavy duty workhorse of a chip... gets added protection by being heatsinked to the, er, heatsink!
Assuming a loss of 3V at the LM317 and sense resistor... probably a reasonable estimate... that implies better than 83% efficiency... IMHO not too shabby! :naughty:As for the emitters themselves: they're very warm white-tinted LuxIII stars substantially underdriven to allow for extremely long runtimes without too much concern for heat buildup. The four stars are super glued together in the shape of a diamond, with copper braid and heavy gauge wire connecting the circuit. The entire array sits on the heatsink, not glued, not even slathered in thermal goop... it sits DRY on the heatsink! Well, not quite... one fringe benefit of this Pentium CPU sink was that it already had a thermal pad mounted on it... the four stars all sit on at least good chunks of that pad, and are held tightly in place from the upward spring pressure of the heatsink assembly beneath.
For those interested, the bins of the four stars are: SX1J, SX1J, SX1J, and SX1K.
LuxIII array.
Time to close 'er up! To my horror, the first time I closed the bezel the thing didn't light. Fortunately, opening the bezel and reseating the heatsink seems to have cured things, and it continues to work even after shipment to MSaxatilus, or so he reports.
:sweating:
Bezel closed.
Time for a test run! This wasn't designed to be a particularly pretty mod, and yet there's a certain beauty to the thing in an industrial sense... plus when lit, one gets a feeling of power, heh heh... :naughty:
Applying the juice!
So how does it work? Does it meet the intended mission? Well, sort of. I'd purposefully used 17mm reflectors in an attempt at more sidespill and less throw, but despite my best intentions the darned thing still manages to pump out one heck of a hotspot!
oo: Actually, I found myself carrying this light around house and yard for a day or two afterward, before sending back to MSax. It's one of those rare lights that actually exceeds a modder's expectations. I was shocked at just how useful the thing was! Based on a quick phone chat, Dave (MSaxatilus) seems to agree. It's a keeper! The obligatory ceiling shot. Note the broad sidespill, and yet with a pronounced hotspot!
(Each ceiling board measures approx. 1.5 inches across, and the light was roughly 1 meter from the ceiling.)
Did I mention the circuit should run 10-12 hours in full regulation?
oo:Thanks for reading, folks! :bow:
