What’s a “Sleeper Flashlight”?
That term comes from what is referred to as a “Sleeper Car”
A sleeper (US English) or Q-car (British English) is a car that has high performance and an unassuming exterior.123 Sleeper cars are so called because their exterior looks little or no different from a standard or economy-class car. In some cases the car appears worse due to seeming neglect on the owner’s part, typically referred to as “all go and no show”. While appearing to be a standard or neglected car, internally they are modified to perform at higher performance levels. The American nomenclature comes from the term sleeper agent, while the British term derives from the Q-ships used by the Royal Navy.
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.
Definitely a sleeper light, cool mod.
Awesome mod!!
Words can be broken,
so can bones.
Nice
Just have one query, the air inside the light is going to get hot fast, and I can not see any vents, try putting some holes at the back for air in and the front for air out, that way the cells, and driver when you get around to putting one in, are kept cool as well.
Cheers David
Nothing to see here folks, move along...
Thanks guys
And it was relatively easy. And like I mentioned, not much risk of screwing up
Anybody need a 6V lantern battery?
Yes you’re right, I will have to do something. Probably holes will be enough for venting. I don’t think I will have to ad a second fan. We’ll see……
By the way, if I drill holes I will lose functionality. This light floats
Orsm. I'd be using an asbestos glove the first time you fire this beast up in anger in case the case turns into the Blob.
djozz quotes, "it came with chinese lettering that is chinese to me".
"My man mousehole needs one too"
old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".
Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.
love sleepers!
PLEASE NOTE
i do not work in "reviews, deals and codes" for the time being
maybe M4D M4X will return one day, but until then:
THANK YOU FOR YEARS OF YOUR SUPPORT AND FRIENDLY CONTACTS!
If I remember correctly the factory is 2.4 amps at 12v for this emitter so you are almost 2x the factory spec. which I thought was something like 4800 lumens.
but maybe my memory is failing me?
from the data sheet
Maximum drive current: 2400 mA (12 V)
Binning condition: TJ = 85 °C; 12 V, IF = 1050 mA
LED junction temperature °C 150
http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/...
(“It’s good that most people can’t remember their previous lives. Otherwise
things would be a lot more complicated than they already are.”
Ajaan Lee Dhammadharo)
Nice mod! Looking forward to the beamshots.
The 12V XHP70 should be at maximum output at 6A, if cooled well, like you do in this mod. But I'm sure it survives a current that is much higher, 8A should be no problem (the XHP70 that I tested in 6V set-up survived 15A with no noticable damage, see OL's XHP70 thread, post #575).
link to djozz tests
nice work!
That Canadian flashlight guy & Lantern Guru -Den / DBSARlight
Gotta love the sleepers!
Love it!
So, other than the XHP70 and base, everything you used was just stuff already laying around the house. Since you could always reused the emitter/base in another light someday, this light really cost you nothing other than some hobby time. Now that is budget at it's best.
Guess you could put a couple small balloons in the light to keep the floating functionality. Just don't test it while taking a bath.
beamshots? i’m drooling…
-Clark
I see you’re on the East Coast too.
Gotta wait for the dark
Mean while I am bench testing and working on an FET switch. No way that wimpy stock switch is gonna handle 6A!
At 12V, that’s 72 watts
lol - I wondered about the switch
Up until now, I have only been bench testing this light. Running it while not assembled and not using the stock switch. The original LED in series with the 15 ohms of resistors probably only drew in the neighborhood of 200 mA. That stock switch probably couldn’t handle 6A, even once. So I built an “FET switch” based on this circuit
This circuit with a low power LED could be used to test various FET’s in a Go-No Go situation. I eliminated the 1K resistor because in this circuit it is a current limiting resistor to power what would have been an indicator LED to signal on and off during the test of the LED. The 2 resistors I had and for the FET I used an automotive FET salvaged from a drill pack. In this case it came from a Ridgid pack, part IRF1404z. It can handle 75A so 6A is a piece of cake! Even with no heat sinking. The stock switch is a push on, push off. Push once and release and the switch stays on. Press again and switches off. Perfect for this application. Now instead of having to pass 6A, it only see a few milliamps.
Nothing fancy, I soldered the 3 components directly to the traces on the back side of the reflector.
At the top of the picture there are 2 connectors that make contact with the switch mounted in the forward top of the light. They connect when the reflector is screwed into the light.
All there is to do now is wait for darkness
Sweet. I need to keep that FET switch circuit in mind.
I updated the OP with beam shots and a short video
(“It’s good that most people can’t remember their previous lives. Otherwise
things would be a lot more complicated than they already are.”
Ajaan Lee Dhammadharo)
Thanks Ronin42, so far, you are the only one to respond after I posted beam shots,
To answer your questions, firstly think of the FET as a valve. In fact the names of the pins are “Drain”, “Source” and “Gate”. A water valve, a “Gate” valve, would have a place for the water to enter (the source) a place for the water to exit (the Drain) and a shut off (the Gate). Open the Gate and the water flows, close the Gate and the water stops. Simple as that.
In the circuit for the FET the Gate is closed when it is low (negative) and open when it is high (positive).
In this schematic, when the switch is open, the gate is low meaning that it is negative. It is connected to negative through the 68K resistor. Close the switch and it becomes high and opens up. Even though the 68K resistor still connects it to negative, the much lower 100 ohm resistor opens it up.
Picture of a Gate Valve
Notice in the diagram they use the terms Gate Up (high) when it is open and Gate Down (low) when it is closed.
As to the tint of the XHP-70, it is definitely warmer than the SRK. When I ordered, it was supposed to be 5000K and I think that is about right. The SRK looks COLD in comparison.
And to answer your third question, I am sure the LED would blow up with 5S. I purposely used weak cells just to be safe. Better cells would not drop
a lot less thanas much as 2 volts.BTW, the Sleep Light puts out a lot of freaking light. Compare it to the cars passing by. (no one would have had their high beams on though)
That's a heck of a lot of light coming out of a plastic light. Must feel a little funny holding a plastic light pumping out that many lumens. How does it feel in comparison to the SRK weight wise?
I really like that, thanks for sharing.
In Him (Jesus Christ) was life; and the life was the light of men. And the light shineth in darkness; and the darkness comprehended it not.
http://asflashlights.com/ Everyday Carry Flashlights, plus Upgrades for Maglite.
LOL, it vibrates!
That poor 12V fan is spinning like crazy running on 16V
It’s a flooder though for sure. Like you pointed out in another thread the reflector is shaped so that most of the lumens just spill out.
I wouldn't think the fan needs to spin very fast to effectively cool that heat sink. You planning on putting a resistor in series with the fan or something when you go to the next level of cells?
Looking forward to hearing how your XHP70 handles 4 health cells.
HAHAHA, that is some awesome sleeper man, excellent work!!!
GB anyone?
Grtz
Nico
That’s pretty sweet! Thought about resistor modding the fan to get the voltage lower?
-Clark
Yes I will do, AHEM, “the resistor mod”
I’m gonna have to open her up too as pommie pointed out. It’s gotta breathe, it gets hot in there!
Heck even a “Sleeper Car” might have a hood scoop, right?
I’ll do it discreetly. 0:)
dchomak thank you so much..
Excellent, Excellent, Excellent
Wow your explanation is one anyone can follow (if I can). I had to look at it for a while but now I get how you are using the FET (look at me throwing big words around)
to be the actual switch. I guess with all the resistors it is not open and closed but more and less closed.
Sorry lazy brain, yes I did not take the time to check the voltages at 4s you are already over the 12v for the emitter. Better to go with 4s2p heck, you have the room.
(“It’s good that most people can’t remember their previous lives. Otherwise
things would be a lot more complicated than they already are.”
Ajaan Lee Dhammadharo)
You definitely got it, but I want to make a slight correction to your thought and 1 more analogy here.
In the picture of the water Gate valve, imagine instead of the gate being connected to a screw that is turned to open and close it, but rather just a simple shaft that can slide up and down. In the position that the diagram is in, imagine that when the gate is down it is because gravity, which is always present, pulling it down. To open the valve you have to “pull up” on the shaft, overcoming gravity. As long as you keep pulling up on the shaft, the gate is open. But as soon as you let go, it falls back down and shuts off. I like to think of that 68K resistor as though it were the gravity that keeps the valve shut off.
I did the resistor mod and slowed the fan done some.
I also did some calculations on what it would take to keep the inside of the light cool. At first I thought I could use these 2 small 25mm fans I had but based on their 2.3 CFM airflow, they are not enough to get the job done.
Those fans in a push-pull configuration in order to carry 60W of heat out of the light would have to exhaust air at 152 degrees Fahrenheit. That’s way too high. Turns out using 1- 50mm fan is enough.
Another strange thing about this light, IT GLOWS
So much for plastic reflectors, the XHP-70 is so bright it just blasts thru the reflector!
great pictures
PLEASE NOTE
i do not work in "reviews, deals and codes" for the time being
maybe M4D M4X will return one day, but until then:
THANK YOU FOR YEARS OF YOUR SUPPORT AND FRIENDLY CONTACTS!
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