# Attempting my first drop-in



## hellokitty[hk] (Mar 15, 2011)

Hello everyone, I think now is a good time for me to start planning to build a flashlight.
Firstly, I want to build the light myself, as much as possible. My budget is flexible, but as far as I can see, it will be <$70 USD.

Here is my rough outline:

Solarforce L2 with tailstanding forward clicky from solarforce-sales
UCL lens, though I've heard that KD's UCL lenses are decent and fit better, plus they have free shipping, so I would like to order from them if possible. 
Redilast protected 18650 2900mAh, I have an apache 1215 charger for LiPoly, but I'm going to assume that will work unless someone tells me otherwise.
XM-L (more on this later).
SB 2.8A driver.
I already have 24 gauge wires from illumination supply.
I also picked up a foot of 12mm copper wire from illumination supply; I assume this is for wrapping the p60 reflector.
I have an OP reflector and brass pill from illumination supply.

Now some details...please bear with me for a moment 
KD's search function (IMO) is terrible, and their site is disorganized, if someone could post an item number for the lens I'm looking for, it would be very much appreciated. Right now I'm looking at SKU S004329 and SKU S008213 , but I'm really not sure especially with KD's poor labeling and such.

I hear that neutral white XM-L's may be coming out this month, so I won't actually be buying the LED for a few weeks, but I'd like to post this thread and get things sorted out already. Also, I've heard that cutter's MCPCB's are poor, and that DX's are actually pretty decent, but I can't say I trust their LED's, so I don't know where I can get XM-L's on good 14mm stars. Maybe I won't even use a star, but that sounds like it could be troublesome. I have arctic silver thermal epoxy.

My understanding is that I need an insulation ring of sorts to prevent the aluminum reflector from shorting is that correct? I read on a thread that sticking to pieces of kapton together and cutting a hole for the emitter is a nice solution but I'll ask anyway. 

Is there anything else that I am missing?
How about thermal transfer...I want it to be able to maintain as much output as possible for as long as possible, so if there is anything else I can feasibly do. One last thing, has anyone tried using the copper tape? It seems to me that you might be able to mold and fit aluminum foil or something better than that copper tape, but I am the noob here.


My warmest thanks to everyone on this forum; the people here have provided fantastic help and show the utmost dedication.

EDIT: I remember someone said they might be able to provide a copper pill for me, but I can't say who since it was lost in that mess.


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## PCC (Mar 15, 2011)

First of all, you'll need a 14mm MCPCB because the 16mm ones will be too large to fit the brass pill. Secondly, the P60 kit you got from Illumination Supply will require a pill that has 26TPI threads instead of the more common 1M threads (25.4TPI). A pill with 1M threads will thread onto the reflector, but, it will not thread on easily. The brass pill that comes with the kit is threaded 26TPI.

PM me about the copper pill.

It sounds like you're on the right track to putting together a nice little light. I would caution you to use the high mode on this light sparingly because of heat issues. A good option would be one of the finned 6P heads that are offered in the classifieds section, though one of those will cause you to over run your budget.


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## hellokitty[hk] (Mar 15, 2011)

PCC said:


> First of all, you'll need a 14mm MCPCB because the 16mm ones will be too large to fit the brass pill. Secondly, the P60 kit you got from Illumination Supply will require a pill that has 26TPI threads instead of the more common 1M threads (25.4TPI). A pill with 1M threads will thread onto the reflector, but, it will not thread on easily. The brass pill that comes with the kit is threaded 26TPI.
> 
> PM me about the copper pill.
> 
> It sounds like you're on the right track to putting together a nice little light. I would caution you to use the high mode on this light sparingly because of heat issues. A good option would be one of the finned 6P heads that are offered in the classifieds section, though one of those will cause you to over run your budget.


Fixed the star size.
I will be cautious about heat. I've gathered that if the light is too hot to handle comfortably, then it should be turned off, but that sounds quite general, and will also depend on your thermal path right?
I have seen some finned heads, but yes they would be over-budget, and I think the L2 looks better aesthetically without fins.


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## srfreddy (Mar 15, 2011)

Where did you hear about Cutter MCPCB;s?


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## hellokitty[hk] (Mar 16, 2011)

srfreddy said:


> Where did you hear about Cutter MCPCB;s?


Source for *good* MCPCBs for XM-Ls


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## hellokitty[hk] (Mar 17, 2011)

It looks like I will not be using a copper pill, I'll just be using the standard copper pill.
Anyway, if there are any more suggestions/critiques.
Also, I thought that there would be 5000K or 5700K neutral XM-Ls out by now, can anyone tell me where to find them?


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## srfreddy (Mar 17, 2011)

There was a preorder including 14mm MCPCB's on the marketplace from cutter-you should expect them end of marchish.


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## hellokitty[hk] (Mar 20, 2011)

Another question...
What is the spring on the outside of the pill for?
I've watched videos of a p60 installed without the spring on it, and I can't think of any use for the spring.


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## wantsusa (Mar 20, 2011)

Outside spring is useful especially on Solarforce L2P makes it fit nicely...don't think it would connect well without the spring. I believe Nailbender usually keeps a full spring for the L2P but for other setups it may need to be cut down or removed...I don't have a L2 so don't know how much it is needed for your setup


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## hellokitty[hk] (Mar 20, 2011)

I've never done/seen this before, all I did was watch someone put a dropin into a surefire host.
In the video, there is no spring, and it looks like it wouldn't even fit if it had a spring on it, so I was wondering why there is a spring in the first place.


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## Sgt. LED (Mar 20, 2011)

The space for the drop-in is bigger in some hosts. If the host has a wide or deep cavity then you have to use the spring to keep constant negative contact. Sometimes it's the *** end of the drop-in that's smaller than need be, same solution though.


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## PCC (Mar 20, 2011)

On SureFire hosts the dimensions of the cavity that the drop-in sits in is a bit tighter than on, say, a Solarforce host. The Solarforce host is cut very generously in this area. The area that the reflector makes contact with the host is usually anodized so there isn't an electrical path there. On the SureFires the pill makes direct contact with the host in the throat area, most of the time, while with the Solarforce you use the spring for this purpose. If you use the spring with a SureFire host then the spring will not allow the drop-in to seat and there will be a gap between the bezel and the body. If you don't use a spring with a Solarforce host then, more than likely, you won't get negative contact and the light will not turn on. If you wrap the drop-in with copper tape to increase thermal contact then this should be sufficient electrical contact that a spring is not needed and the light will turn on.


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## hellokitty[hk] (Mar 20, 2011)

Oh I see...thanks, that really was a newbie question.


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## hellokitty[hk] (Sep 13, 2011)

Okay, I finally got it done.

There is a bit of a problem though, and it's annoying me a lot. Scroll to the bottom. Also, one roll of 12 inch copper tape was not enough, and (I have no affiliation, and I am not saying that illumination supply is a bad dealer) I believe that the tape is too small width wise too. IMO the 4mm copper tape that Shao has at Shaotech fits better.

Here it is:

All supplies ready.






Reflector, driver, copper heatsink, brass heatsink (unused), in order.





LED's.





Cleaned and shiny.





Nevermind, now all supplies are ready.










Stick the LED on using Arctic silver thermal epoxy.





Center LED (no, it's not centered in this picture).





Stick driver in.





Test fit leads.





Solder leads. Messy flux on the sides. It's 26 gauge 19 strand silver-plated copper wire with teflon insulation; this insulation did not melt.





Testing...didn't screw up yet.





Electrical tape to prevent shorting against the aluminum reflector.





Wrap the reflector in copper tape to keep it snug inside the body. More solid electrical connection, and much much better heat transfer to the body, and the outside air. I actually didn't have enough and wrapped it with aluminum foil too.





Stuff everything in, and the finished product compared to a standard, cheap 2D incandescent. Outdoor beamshots next.





Backyard, control shot with 2s shutter, 1600 ISO, auto white balance, Cannon T1i.





2D, 2s shutter, 1600 ISO, auto white balance, Cannon T1i.





My flashlight, same settings.





2s shutter, 800 ISO (I think).





Same settings.





1s shutter, 800 ISO (I think).





Same settings.





.5s 800 ISO (I think).





Same settings.





There's something wrong with the modes though.
It worked fine when I was testing it outside the body, but I only did that for a few minutes. It cycled right through the three modes. I noticed that the lowest mode had a slight whine, the medium mode had a strong whine, and the highest of course had no whine.
Once I put it in the light, the modes stopped working. It worked for a few minutes, then it would only output high. What's really weird is that I can still hear the whining if I cycle through, and it goes in the same order: low whine, high whine, no whine, repeat. There isn't a difference in brightness though, so I'm very confused.
I tried taking it out, it worked and cycled through the modes just fine. Memory worked too. I played with it a bit outside of the host to see if it'd mess up, but it's fine. I checked all the soldering around the stars, and they all look clean except the third one. I don't see any messed up contacts. The battery is in there tight enough. If I use a wire instead of the tail switch, it still has the problem. The head is stuck in there pretty good with the copper tape and aluminum foil, so I think it's getting solid contact. The driver is soldered to the pill nicely as well. It happens with both my batteries.
A few hours later, I dropped it from about one meter onto hard rock. A bit of a chip... But the driver started working perfectly!..?!?!
Cycled through all three modes, and I could still hear the soft whine from low, and loud whine on medium. 
Worked like that for a while, but then high stopped working. It would switch to high for a split second, then step down to medium and continue cycling to low. I thought it was my batteries going low, but after a few minutes of me screwing around with switching modes, it started working again and it stayed on high for at least a good ten - fifteen minutes. 
Later, it kept showing this problem intermittently. It also did this thing where it would stay on low, but flash once per second. I thought it was a connection problem at first, but it just sat there flashing regularly.
It's very sensitive to movement/bumps. Sometimes it'll bump and randomly switch modes if I set it down gently. I know it's not the battery failing to make contact because I've shaken it, and bumped it with much more force, and the battery is still connected.
At the moment, it's only staying on high right now, though I still hear the whine on medium and low.

Really confused


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## Norm (Sep 13, 2011)

:goodjob: Looking good 

Moved to Homemade and Modified Flashlights Discussion - Norm


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## hellokitty[hk] (Sep 13, 2011)

Eh, that mode thing is pissing me off though.........Sometimes it works properly if I bang it.


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## glockxj (Sep 13, 2011)

Wrap the drop in with aluminum foil. Sounds like the drop in isnt getting good contact.


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## hellokitty[hk] (Sep 13, 2011)

As I said, it's in there tight. I can't pull it out actually.
So, yeah, I'd rather not have to take it out, but if that will help fix the problem.


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## Norm (Sep 13, 2011)

Are you using a large spring for the body contact?
Norm


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## PCC (Sep 13, 2011)

Those drivers work by regulating the negative and shorting the negative gives you direct-drive, but, the driver still tries to do what it was intended on doing. Check the wire where it is soldered to the driver, it could be shorted there if the other end of the wire at the LED is fine. What might be happening is that the tail cap spring pressure is forcing the driver board forward into the back of the pill and causing the short.


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## hellokitty[hk] (Sep 13, 2011)

This looks pretty big...though the driver's spring is a bit small I guess...
It's a solarforce s6.


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## Norm (Sep 13, 2011)

Norm said:


> Are you using a large spring for the body contact?
> Norm


 Sorry I wasn't very clear, I meant are you using a spring on the bottom of the drop in?






Norm


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## hellokitty[hk] (Sep 13, 2011)

I am using a small one at the bottom of the driver, not on the side though.. It is small though; you can see it pretty clearly above.


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## Be-Seen Triker (Sep 13, 2011)

Norm is talking about the large diameter spring on the P60 dropin.

I'm going out on a limb and say you are shorting the negative emitter lead to the reflector...
This tape solution isn't the best insulator and you may actually be shorting to the emitter small pcb itself (the small silver rectangles on the green board).






...and by now you might be only a drop or two away from shorting the driver out all together.
but this is only a quess


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## bshanahan14rulz (Sep 14, 2011)

This sounds like the problem to me too. AMC7135 regulate the current on the return path of the LED. If it shorts at that spot after the LED, it will just drive on direct drive the whole time, and the chips will still be seeing their own Vcc and ground path, but no load connected. 

I cut out a disk from relatively thin plastic, think water bottle thickness, but flat, such as overhead projector transparency sheets. Then I use a hole punch to punch a hole in the middle. 

With elecrical tape, there is enough grip to it that it may stick to the underside o the reflector.

Other than that, this looks like a great build, congratulations! And thanks for documenting all the parts you used. It will be a good resource for anybody else looking to do the same.


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## hellokitty[hk] (Sep 14, 2011)

Thanks everyone.
I should have thought of using a bottle cap and cutting it out...Doh! I'm sure I have plastic or something somewhere.
Anyway, I taped a round circle of electrical tape on the bottom of the reflector, and also two new ones on the leads just in case. The last ones did look like they were slipping.
I'm going to use it for a few days and see how it goes. So far, it's been okay.

I think it starts blinking when I hit the low-voltage warning...I noticed it was on high for a few seconds, then went to low and blinked regularly, about every second or second and a half. I checked the battery and it was getting a bit low. Aside from that, I think it's working properly!


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## Be-Seen Triker (Sep 15, 2011)

Good job! Yes, the NANJG 105C starts to blink when it 2.85V under load. The battery will recover quickly from that state when you remove the load of an XM-L.


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## hellokitty[hk] (Sep 15, 2011)

Seems to work just fine now...thanks everyone.


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## hellokitty[hk] (Sep 20, 2011)

Sorry everyone, but I think I might have another problem...
The low voltage warning (low mode, blinking) seems to go off a lot earlier than it should.

It doesn't really seem to happen when it's supposed to. I'm using a redilast 2900 and a solarforce 2400, both of which can hold their voltage decently. I know it's not my battery sagging too low under load because all I need to do it cycle through, or sometimes shake it a bit and cycle through to high, and it works just fine. I just tried with a nearly full battery, and I still manage to keep it going on high for over half an hour after it first started showing the low-voltage warning. I just had to bump it around a bit and cycle to high again to get it back on high.
It happens randomly, but it always does work properly when my battery is actually low.

It does seem like a loose contact of some sort, but I haven't a clue where it could be.


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## Be-Seen Triker (Sep 20, 2011)

Two possibilities. One I worked on last night was to add a small extension to the small spring on the driver. Easier said than done since you really don't want a failure there. The host I use is a 504B, similar to your L2P. The battery simply wasn't being held in there very tight and every bounce would let the positive end disconnect. With the added 1/8" extension, it is working well enough for my purposes. Just don't kluge anything on the plus end. I would try taping up a few pennies or dimes and dropping it in on the negative end.

Second posibility is one of my pet peeves with high current flashlights. Very few have a quality switch that is meant for anything over 1.5 amp operation. I went so far as to inquire what Ultrafire was using in their very hot 980L XM-L light. Turns out they use a KAN-28 switch rather than the more common Omten PBS-101. If the problem is not inside the switch, it might be how the switch is providing ground. It is worth taking apart and checking the type of switch and the solder connections of that switch to know if it is suspect. 

I have put perfectly good switches on a test circuit and they would poop out 1.5 amps all day which is more than sufficient for XP-G's and XR-E's or higher voltage lights... into a 3 amp circuit. Bypass the switch or put in the KAN-28, and I get the full 3 amps, no quams.


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## hellokitty[hk] (Sep 25, 2011)

Hello again everyone.
I'm pretty confident that I've finally gotten the (or maybe a) problem solved.

As it turns out, if you screw on the L2P head all the way down, _it does not push an illumination supply p60 pill all the way in_. It was stuffed in pretty tightly with foil the first time, so I thought I'd just screw the top on to squish the reflector and pill in. There's still ~2mm more that it can go in.

I'm guessing that caused a weak contact somewhere, I'm not sure where, as I think that battery was still in there pretty solidly. I saw a minor indent on the top of my Redilast battery and the back of both of my batteries have slight markings where the spring makes contact.

For some reason, even though it was pretty difficult to stuff the pill in, it would not stay all the way down. In fact, I needed to use pliers to pull out the drop-in, so I don't understand why it wouldn't stay in without the top screwed on, but oh well.

I pulled out the drop-in and re-wrapped the foil. At the same time, replaced my tape solution with a plastic ring I cut out of a blister pack. I hope it won't melt. It was even harder putting the foil in this time around. I had to put about 25kg of pressure to stuff it in. It's not coming out this time... It's already got a bit of a dent on the side from using the pliers the first time.

Thanks for all your help, it's working fabulously now !


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