Hmm. . . Mod these junky incandescent power tool "flashlights" with LED MR16 bulbs. Great Idea!
-Thanks.
Works like a charm too because the built in driver on the mr16 steps the voltage and the current down so it works on any crappy incandescent 12v and up. These MR16s are down to 3 bucks or so for 6w which is decent power.
12v and up? How far "up"? I've got a "19.2v NiCd" one.
-Garry
Good question, Makita 18v Lithium packs are 21v when fully charged
I never thought of putting an MR16 in any of my cordless drill flashlights! Nice!, now I can have more projects to do 
GottaZoom is right, 18V cordless drill batteries charge up to over 20V. I seem to remember that the MR16’s that I first bought could run on 12-24V. I looked at a couple on the internet, but I could not determine that.
So, I took an extra that I had, standard 3W warm white MR16, and hooked it up to my power supply. Here are the readings.
10V - .06A
12V - .21
13V - .29
14V - .29
15V - .27
16V - .23
18V - .18
20V - .15
22V - .12
24V - .10
and for good measure, I ran it up to 26V and got .09A
This is voltage to the external pins of the lamp and current through the external pins, not the current to the LED’s
The perceived brightness was at a maximum at 14V and decreased slightly from 16V on upwards to 26V. It wasn’t much, but it was noticeable. I will measure the current to the LED’s and post that also. It could be that these lamps are regulated and maybe 18-20V input is no problem. If that is true, then these lamps in cordless drill flashlights would be a sweet setup with no modifications to the lamp at all.
I took the lamp apart to measure the current to the emitters at the various input voltages. I wanted to separate the driver from the lamp for the bench test and this is what i found.
Even though I didn’t run the lamp very long in the previous testing, the driver got hot enough to melt the plastic housing. It still works OK, but I don’t think we could count to last too long at higher input voltages. I have some more of these lamps, I will disassemble another and do the measurements including the temperature of the driver while it is running at 21V input.
Here are pics of that same driver from another post of mine, My $3.96 florescent worklight Mod
Thanks Dave for testing! Would make a really sweet setup to use these!
- Garry
off topic maybe,
Put one of these in a Makita drill for 7.2 volts?;
http://www.fasttech.com/products/0/10002233/1292001-218650-battery-case-with-lead-wires
Or are there better quality ones that stands more amps?
I retested running the driver in the stock MR16 on voltages up to 24V and it is fine. It doesn’t even get hot. It will be fine, as is, in a cordless drill flashlight up to 18V. What I saw and thought was melted plastic turns out to be glue to hold the driver in the base of the light.
Oops.
