What’s a “Sleeper Flashlight”?
That term comes from what is referred to as a “Sleeper Car”
So a “Sleeper Light” would be a high performing light that looks like an average every day light.
My mod started off with one of these:
Found at Home Depot. It comes with a 6V lantern battery and costs $5.25. Extra batteries for it are for sale just below for only a little less, $4.68. Little risk here, if the mod goes south I still have the battery.
Here is a shot of the emitter itself. Interesting reflector and the emitter is on a star of sorts. That original emitter is only good for 50 Lumen.
Next I removed the Bezel-Head-Reflector assembly. No need to use strap wrenches as it came right off!
The “star” is held onto the connector-heatsink plate with some protruding plastic posts that were then melted.
What I have in mind for this mod is an XHP-70 on a copper star afixed to a heat sink with a fan mounted to that, running off a 4S1P 18650 pack. I am going to try Direct Drive in this light, no driver. The copper star for the XHP-70 will be configured for 12V.
There certainly is room for all that.
First thing I had to do is remove the mounting plate (the ONLY metal in the whole light) to get at the original LED
Once I got that off, I could remove the LED.
This is the original “star”, the “driver” is merely 3 - 43 ohm resistors in parallel for a total of about 15 ohms. This to limit the current to the LED. Trouble with this type of driver is the loss across the resistors is energy just thrown away. On the light it says that in stock form it will run for 100 hours. I bet it could run twice that with a proper driver. (I’m guessing a 3V drop across the resistors and a 3V drop across the LED, running off the 6V battery.
Then I took an old CPU heat sink and drilled and tapped mounting holes for the XHP-70 on copper star. Those mounting screws are 2-56 and they are small.
Configured on the star for 12V
Then I had to drill and tap 4 more holes for the mounting plate.
To tap such a small hole with a delicate and brittle tap, I like to insert the tap in the bench drill chuck and turn it by hand.
I couldn’t find the original 50mm fan that went to the heat sink but I did find one in an obsolete Standard Definition TiVo that I had. It pained me to cannibalize it, but what good was it, the world, and I, have moved on to HD.
Next thing to do is make up a 4S1P battery pack. I got this spacer from an old Makita drill pack I found in the recycle bin.
I used 4 laptop pulls that I also found in the recycle bin and wired them up in series.
At this point I am a little nervous about running this in direct drive so I am not yet using my best cells. In fact I only charged these up to 3.85V each. Even so when I bench tested this configuration, the LED drew over 4A. With the heat sink and fan the LED hardly gets warm at 4A, but how much farther can it go?
This mod is essentially done, the only thing to resolve is will it blow with 4 cells in series charged up to a full 4.2V each?
Then what about using IMR’s?
I couldn’t do any beam shots tonight as it is really pouring outside, there are flash flood warnings etc. I’ll get that done tomorrow night.
oh yeah, the business end of the light, the only giveaway of what this “Sleeper Light” really is
8/12/2015
Beam Shots and a Video
My SRK 6 x XM-L2 modded, 3A per emitter, 18A total (no copper)
Sleeper Light XHP-12V copper on 4S1P fully charged “tired” used laptop pulls 5A
It can do better, those tired laptop pulls drop 1.9V upon startup. I will now make another, better pack with new cells. Not ready to try the IMR’s yet though
In the mean time, here is a video comparing the 2 lights. The SRK is up first and is cooler. Also the push on, push off switch on the sleeper is noticeable and quite loud.