Modifying a Milwaukee M18, need suggestions on parts (led, driver, etc)

sactime

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Dec 13, 2007
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Hello,

It's been a long while since I've modified a flashlight and I'm out of date with current tech (last I knew the P7 was the LED to have).

My Milwaukee M18 led light is pretty sad and puts out minimal light. I'd like to upgrade the led and need suggestions on which LED and driver to use (18v input). Ideally I think it will come down to heat and efficiency since I'd like to be able to run this light for at least 30 minutes without worry of overheating. I think I'd like to stick with single mode, but am open to the idea of two mode (low and high).

I attached some photos of the Milwaukee taken apart.

Is 1000 lumens possible without major upgrades to the heatsink? Thanks!
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LEDphile

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Mar 8, 2021
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313
Unless that head is metal, you're likely already thermally limited. That LED looks like one of the "high efficiency" packages from Cree (XT-E or XP-G families), and should be good for north of 400 lumens out of the package. Milwaukee, on the other hand, rates their unit for 100 lumens, suggesting they are not driving at max current. Given that a 3AH pack should be good for 8+ hours of operation at a 2A LED drive (max for XP-G family), there's almost certainly some other reason for the low lumen output. My guess is thermal, given that there doesn't look to be much heatsink in that head.

But if you do want to try driving the LED harder and don't mind stressing components, I'm guessing you should be able to modify the current-set resistor on the driver for higher current with only minimal work (once you have determined which part on the driver board that is, of course).
 

sactime

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Dec 13, 2007
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The head is aluminum. I attached a photo of the area behind where the led is mounted.

I'll be honest I do not know enough about how to modify the resistor on the current driver. It might be easier for me to get a compatible led and driver and wire them together.

Thanks!
20220904_134730.jpg
 

YourFriendBen

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Feb 9, 2023
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Unless that head is metal, you're likely already thermally limited. That LED looks like one of the "high efficiency" packages from Cree (XT-E or XP-G families), and should be good for north of 400 lumens out of the package. Milwaukee, on the other hand, rates their unit for 100 lumens, suggesting they are not driving at max current. Given that a 3AH pack should be good for 8+ hours of operation at a 2A LED drive (max for XP-G family), there's almost certainly some other reason for the low lumen output. My guess is thermal, given that there doesn't look to be much heatsink in that head.

But if you do want to try driving the LED harder and don't mind stressing components, I'm guessing you should be able to modify the current-set resistor on the driver for higher current with only minimal work (once you have determined which part on the driver board that is, of course).
The head is aluminum. I attached a photo of the area behind where the led is mounted.

I'll be honest I do not know enough about how to modify the resistor on the current driver. It might be easier for me to get a compatible led and driver and wire them together.

Thanks!View attachment 31640
Awesome, wondering the exact same thing and then only could find this on all of the vast the world wide web. Glad you asked this and great place to ask. I joined just for this but glad to be in an LED skilled site!

How did you get the screws out of your flashlight housing? Looks to be half the battle.
 

YourFriendBen

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Feb 9, 2023
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Location
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Unless that head is metal, you're likely already thermally limited. That LED looks like one of the "high efficiency" packages from Cree (XT-E or XP-G families), and should be good for north of 400 lumens out of the package. Milwaukee, on the other hand, rates their unit for 100 lumens, suggesting they are not driving at max current. Given that a 3AH pack should be good for 8+ hours of operation at a 2A LED drive (max for XP-G family), there's almost certainly some other reason for the low lumen output. My guess is thermal, given that there doesn't look to be much heatsink in that head.

But if you do want to try driving the LED harder and don't mind stressing components, I'm guessing you should be able to modify the current-set resistor on the driver for higher current with only minimal work (once you have determined which part on the driver board that is, of course).
oooh this helps a lot to know what could be done to fully get the potential of the LED already in the in it. What insight! For those that don't know cobs and the details yet of different models this good to know the a new LED isn't the solution.
As for pushing the driver harder, that would require a new pcb module? The current set resistor can be variably adjusted or soldered off and a higher capacity one soldered in to replace it?
 

YourFriendBen

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Looks to be plenty of room to add a small 1" fan and pull air through the head. Drill a hole and add a 2nd switch to activate.
that's a neat idea rather than shoving some smaller cpu heat sinks into the body cavity trying to make contact with the head's metal housing.
 

YourFriendBen

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Joined
Feb 9, 2023
Messages
4
Location
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The head is aluminum. I attached a photo of the area behind where the led is mounted.

I'll be honest I do not know enough about how to modify the resistor on the current driver. It might be easier for me to get a compatible led and driver and wire them together.

Thanks!View attachment 31640
Sooo curious how you got the screw out of the housing, im enthusiastic to ask again : p
 
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