# Can an 18500 battery replace 3xAAA carrier (in Techlite Lumen Master 250)?



## ohaya (Mar 10, 2013)

Hi,

I'm new here (been lurking for awhile), but I was wondering if anyone has replaced the 3xAAA carrier in one of the "Techlite Lumen Master 250" lights (from Costco)?

I've seen some posts that indicate that an 18500 battery would work, but I was wondering about if that'd be the case for this light, specifically? Will it be just a simple drop-in (with something wrapped around the battery for the width) to replace the carrier?

The battery that I'm thinking of (actually I already bought one, from a U.S. seller - waiting for arrival) is this one:

http://www.amazon.com/gp/product/B00ABE7J72/?tag=cpf0b6-20

Thanks!

Jim


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## ohaya (Mar 10, 2013)

Hi,

A couple of pieces of info that I omitted in my "2nd" post above:

- I was wrong about the "nub" on the positive end of the carrier. It is not stationary, but rather is spring-loaded.
- I tried measure the length of the carrier to the tip of the nub. I don't have a caliper, but it was ~2.25 inches.

Now I'm thinking that an 18500 will be too short to use as a drop-in (49.8 mm, according to this: http://en.wikipedia.org/wiki/List_of_battery_sizes), so I'm wondering if an 18650 might work (68.16 mm, according to this: http://www.lighthound.com/AW-18650-Protected-2900-mAh-Rechargeable-Lithium-Battery_p_3671.html, and 65.2 mm, according to this: http://en.wikipedia.org/wiki/List_of_battery_sizes).

So I guess that I'm back to my original question: Has anyone actually tried this, with this specific light?

Thanks,
Jim


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## florinache (Mar 11, 2013)

I replaced the AAA's in two of my cheap chinese flashlights with 18650 li-ions, unprotected. The battery was in both cases a bit longer than the carrier and probably they-re not waterproof anymore because of that. A rubber ring or some tape could be a solution if that's a problem. For me it was a good compromise for tripling the running times.


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## ohaya (Mar 11, 2013)

florinache,

Did those cheap lights have a 3-AAA carrier, like the Costco light has? I have both an 18500 and an 18650 coming in, so I'll try both, to see how it goes. I found a Youtube video (http://www.youtube.com/watch?v=Y0EnHCAW2hA), where a guy had altered the carrier to put a different battery (a "Soshine" from DX, I think) into an older version of the Costco lights (a white carrier, rather than the black one like in the ones I have), but I'd prefer a "drop-in" replacement, because there was one part of that video where he had to use a spring to bridge the positive side, which seemed kind of "iffy" to me.

I'll post back after the batteries get here and I've had a chance to try them.

Later, and thanks,
Jim


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## florinache (Mar 11, 2013)

They had a holder with + at one end and - at the other, as in a normal battery. In the clip he-s using cr123 batteries which are shorter than 18500. (I think they-re 16340). So, it may work if you put in 18500. If it's too short you can attach a spring to the tailcap. 
Try to stay away from ultrafire batteries, they are mostly used laptop cells, rewrapped in China. http://www.candlepowerforums.com/vb...!!-Misleading-budget-battery-and-lumen-claims


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## ohaya (Mar 11, 2013)

Hi,

Thanks. 

I had made a post with additional info that didn't make it here (not sure why, but I'm past the 3 posts startup now - YEA!). 

Anyway, the lights already have a tailcap spring, and it's a quite large one, so maybe the 18500 would work. I think I have both an 18500 and an 18650 coming in (plus a 14500 - another story). The 18650 is an "EagleTac", but the 18500 is an "Ultrafire". I only got the latter because it was available from WV, which is close to where I live (Northern VA area), just to try this "quickly".

Again, I'll post back. I'm hoping that the large, already-existant spring will make the 18500 work, because I only got the 18500 for this "experiment" (no other use for it).

Will post back.

Jim


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## ohaya (Mar 11, 2013)

Hi,

Fortunately (or, maybe UNfortunately), I've gotten around to reading some of the "poof" threads here (I ignored those earlier ), and now, I a have an additional question about the Techlite 250 and an 18500 or 18650. If either of those fit, do any of you think that there'd be any problems with this combo "electrically"?

It seems like there *shouldn't* be? It seems like 3xAAA would be ~3.6V - ~4.5V, so the 3xAAA normal battery setup would be more, voltage-wise than approx. the lower of those (~3.6V), but what about current-wise? 

Are there situations where the light could be designed (or mis-designed) such that putting in an 18500 or 18650 would cause a problem? I'm picturing something like where the light is draws a bunch more current than the 18500 or 18650 are designed for? Remember, I'm new here, so it's probably more the other way around, but I'm just being cautious here.

Thanks in advance, and sorry for all the possibly dumb questions !!

Jim


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## ohaya (Mar 13, 2013)

Hi,

Well, both the 18500 and 18650 arrived.

I checked the 18500 using a voltmeter, and it shows 3.90V. That seems too high?

The 18650 is way too long. Couldn't even close the tailcap.

The 18500 is shorter than the original 3xAAA carrier, so I could close the tailcap, and the battery seems to be stable (not moving around) with the tailcap closed, but the light wouldn't come on with the 18500 inserted. 

The spring on the tailcap is quite long, so it seems like there should have been contact, so I'm not sure why that didn't work?

Jim


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## ohaya (Mar 13, 2013)

I've tried a couple of times with the 18500, and at this point, I really don't think that it's the length that the issue, but rather how long the "knob" on the positive end of the battery is, i.e., I think that "knob" is not long enough to contact this "gold-colored" part at the front of the light (inside). The original carrier has a knob also, but it's about 1/4" long, and spring loaded.

Jim


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## HotWire (Mar 13, 2013)

I've put 18500 cells in lights with 3AA carriers. No problems. I don't know about your Techlite, though.


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## ohaya (Mar 13, 2013)

Hi,

Thanks. I'm pretty sure that this can be done, so not sure why it isn't working.

Is there any (easy) way to check for contact when the light is closed up? I mean when the tailcap is on? Since it's all closed up at that point, I'm not sure how to do that ...

Jim


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## ohaya (Mar 13, 2013)

I think that I've figured out what's wrong. I followed the troubleshooting steps on the budget forum, and shorting the end of the battery to the body produced no light. So, I was looking closer at the inside of the light, and it looks like the contact area at the front is recessed quite a bit, whereas the knob at the end of the 18500 battery is quite short. I'll post pics below. 

Given that, is there anyway to make the knob at the front of the battery longer, so that it can reach that contact area?

Looking at the inside/front of the light. That circular golden area is recessed, maybe a couple of mm:








Comparison of the 18500 top vs. the 3xAAA carrier top:








Thanks,
Jim


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## ohaya (Mar 14, 2013)

Hi,

I've gone ahead and ordered some of the "larger" magnetic spacers from Lighthound, e.g.:

https://www.lighthound.com/Magnetic-Spacer-for-Charging-CR2-or-14250-Battery_p_1048.html

to see if they might "safely" work on top of the 18500 battery.

Jim


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## ohaya (Mar 15, 2013)

Question: How strong ARE those mag spacers?

I've never worked with them personally, but I've heard they're quite strong, even the tiny ones?

I was thinking of dropping one of the cylindrical ones that I order from Lighthound, into the barrel of the light, and then trying to move it into position on that golden part at the front (see pic I posted above), but I'm wondering: Are the magnets so strong that I won't be able to budge them once I drop them down the tube (about 3-4") using something like a non-metal stick or something like that?

Jim


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## RI Chevy (Mar 16, 2013)

I bought this sleeve to use with an 18500 to replace my 3-AAA carrier for use in my Solarforce L2i. 

http://www.fasttech.com/products/0/10002938/1219900-3-x-aaa-to-1-x-18650-battery-converter

It is for an 18650, and it fits perfectly inside the host to replace the 3-AAA carrier, but just needs to be cut down for length to fit my specific purpose. I am awaiting 18500 batteries for the final fit. I will need to use a spacer or magnet. I'll report back when I do get it working. An 18650 will fit in a L2i, but the pring in either the drop in or the tailcap will need to be removed or shortened, or both. The host is plenty long enough. Just a work in progress for me. LOL


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## ohaya (Mar 16, 2013)

RI Chevy,

I saw that on Fasttech, and will probably order a couple next time I order from that.

However, in my case, the problem is not the diameter of the tube, nor even the length of the tube, but that the way that the light is designed, the positive contact is kind of "sunken", so even with a button/nipple top battery, the battery won't contact the positive side.

That's probably why the carrier that came with the light has a spring-loaded thing on the positive end, that projects about 1/4" from the front of the carrier.

Kind of like this:


| BATTERY |
| |
| |
| BUTTON |
========== |===|============ 
=========| ==== |===========
| |
===========================
Light's Positive contact


Jim


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## ohaya (Mar 18, 2013)

Hi,

I got some magnets in from Lighthound.com today, and they fit perfectly on the battery, but, it still doesn't work.

Here's a picture of the battery with the magnet, side-by-side with the original carrier:






I've ohmed the magnet, and that seems fine (low resistance), and I checked the voltage from the top of the magnet to the battery negative, and that's fine (~4.15V). 

I checked the voltage of the carrier, and that was higher, about 4.5V.

Could that (the voltage difference of the 18500 (4.15V) vs. the carrier (4.5V)) be the problem, i.e., the voltage of the 18500 is not enough to cause the flashlight to light?

Thanks,
Jim


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## RI Chevy (Mar 18, 2013)

What drop in are you using? Try it with a low voltage (.8 - 4.2v) drop in and see if it lights up. I doubt that is the issue. Using 3-AAA rechargeable cells should only give you about 3.6 to 3.9v's total. 4.15v's from the 18500 should be more than enough to light up a drop in.


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## ohaya (Mar 18, 2013)

Hi RI Chevy,

I don't understand what you mean by "What drop in"? I literally took the 18500 like shown in the last picture above (wrapped in paper towel  so battery would "fit" the tube, with the magnet on the battery's button), and inserted into the light after removing the carrier.

To make sure that the problem wasn't that the magnet was "off-center", I also tried (1) dropping the magnet into the tube, then (2) maneuver the magnet so that it was standing at the center of the golden-colored positive contact area at the front of the tube, then (3) slid the battery carefully into the tube. That didn't work either.

I also tried, instead of screwing the tailcap in, to slide the magnet+battery in, then short from the negative end of the battery to the uncoated threads inside the tube, and that didn't work either (BTW, doing the same thing with the carrier in the tube worked).

Also, I reconfirmed voltages:

- 18500+magnet = 4.15V
- Carrier+3xAAA = 4.50V

I'm really puzzled about this, as I was pretty sure that it would've worked !!

Jim


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## ohaya (Mar 18, 2013)

Question: One of the things that I was worried about before I tried this was whether the magnet would stick to the golden-colored contact area at the front of the tube, rather than to the battery top, because if it did that, I'd have to somehow get the magnet out later. But, what I'm finding is that the magnet isn't sticking to that golden-contact area at all. Shouldn't the magnet be attracted to that golden contact area?

As I said in my previous post, I had dropped the magnet into the tube, and then moved it around so that it was standing in the center of that golden contact area. When I did that, it didn't feel like it was being attracted to the golden contact area at all.

Jim


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## ohaya (Mar 18, 2013)

Hi,

This is just not making any sense at all !!

I did the following tests:

1) Using the original carrier, outside the light, I used a wire to jumper the positive end of the carrier to the golden/positive contact at the front of the light, and another wire to jumper from the negative end of the carrier to the threads inside the light tube. The light turned on.

2) I did the same as #1, but using the 18500 battery, and the light did not turn on ...

I checked the voltages again, and still about the same:

- 18500+magnet = 4.15V
- Carrier+3xAAA = 4.50V

So I removed the 3xAAA alkaline from the carrier, and replaced them with 3xAAA rechargeables I had, and measure the carrier voltage. That was ~4.00V.

So now the carrier voltage was less than the 18500 battery, right.

I put the carrier into the light, and tried it, and the light lit!!

In other words, the problem with the 18500 not working is NOT the voltage difference.

So, I am really puzzled at this point, and I don't have any idea why the 18500+magnet would not work !!

Does anyone have any ideas?

Thanks,
Jim

P.S. Re. the question in my post #20: Did some googling, and apparently copper is not attracted to magnets, which answers that question at least ...


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## RI Chevy (Mar 18, 2013)

I was just inquiring as to what type of drop in (LED) that you are using in the light. I am not familiar with the light you have listed. I know other members have used this setup in the past to replace the broken 3-AAA battery holder.


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## Poppy (Mar 19, 2013)

ohaya,
Looking at the magnet and the button top of the carrier, it appears that the diameter of the magnet may be too large. I suspect that the magnet is not reaching the bulb positive terminal.


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## Up All Night (Mar 19, 2013)

Contact issues with the magnet diameter could be possible, but since you've "jumped" the battery with wire leads and the light remained dark, I think you may be dealing with a battery issue. The battery may read 4.15V open circuit, but under load it can't provide any useful energy. I've run a 200 lumen version of this light with an AW 14500 LiCo cell by stretching the tail spring & wrapping the cell. 
You can search the forum for "testing battery voltage with a resistor" to get an idea of what this battery is doing in a closed circuit.
I have no experience with xxxfire batteries, everything I've read here over the years indicates they are iffy at best.


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## ohaya (Mar 19, 2013)

Up All Night,

BINGO !! It was the 18500 battery!!

I was thinking about the problem on my way home today, and thought, "maybe not enough current?", but then I kept telling myself that the 18500 was a new battery, plus it was showing 4+ volts on the meter, so kept discounting it. Then I kept thinking "too bad I don't have another 18500", and then saw your post above about using a 14500 instead. I have a few of those (EagleTacs), but I didn't think about using them for this. So, when I got home, I wrapped one of those temporarily, then moved the magnet to the 14500, and tried it and BLAM! LET THERE BE LIGHT !!

Goes to show that I shouldn't discount possibilities ...

Question: I'm assuming that the 18500 is not good at this point (obvious, huh ?), but is it possible that ALL 18500s wouldn't work, or do you think that it's just this one, particular 18500 (and maybe brand/seller/whatever)? 

If it's not ALL 18500s, I'll go try find another 18500 from another seller/brand, because it has a lot more capacity (mAh) than the 14500s that I have do.

Thanks!

Jim


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## ohaya (Mar 19, 2013)

Hi,

For the record, the magnets that I got were from Lighthound.com:

HCR2Mag	Magnetic Spacer for Charging CR2 or 14250 Battery

LH14Mag	Magnetic Spacer for Charging 1/4" x 1/4"

The first one above was the first one I tried, and it's slightly longer than the 2nd one. Both of them worked with the 14500.

I just ordered some additional magnets, and also one of the protected and one of the unprotected 18500s they carry (figure I'd try them both). Seems like the 18500 batteries are somewhat hard to find?

Thanks,
Jim


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## Up All Night (Mar 19, 2013)

I'm pretty sure that battery is toast. Any quality 18500 will work, the capacity is far greater than a 14500. Make sure your cell is in the light securely, 
especially when using a magnet as a contact. RI Chevy's link for the sleeve looks good.
While my 14500 experiment was done WITHOUT a magnet I still wouldn't EDC it without a more secure method of housing the cell. 
My next battery order will include an AW 18500 to stick in the 160 lumen XP-E version of this light that is part of my daily carry, easily my most used and abused light for the last three years.
You may want to pay attention to how hot this will get on extended runs, the 200 lumen XP-G version gets a little hot near the hour mark running on "duraloops".
Good to see you were successful!
:thumbsup:


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## ohaya (Mar 19, 2013)

Up All Night,

I don't think (actually, I know, because I tried) either the 14500 or 18500 would work, because of what I tried (unsuccessfully) to illustrate in post #16. I don't know what the 150 lumen or 200 lumen lights look like, but in the 250 lumen ones that I have (and I now have 6 of them), the "gold" positive contact area is "sunken", I'd guess, a couple of millimeters, below a metal plate. So what happens with just the battery, without the magnet, is that the shoulder of the battery will hit that metal plate first, but the button on the battery is not tall enough to reach the contact area.

It's gotten to the point where I can actually "tell" when I make contact with the gold contact area when I drop a battery into the tube:

- If I have contact, the sound is more like a "tick"
- If I don't have contact, the sound is more like a "thud".

I'm not kidding ...

So, with no magnet, when I drop the battery into the tube, I hear a "thud". With either of the magnets I showed from Lighthound.com, I hear a "tick".

BTW, I also have some 1 mm magnet discs that I got from Lighthound.com. Those give me a "thud" (i.e., no contact).

Re. the sleeve: Yes, I'm planning to order several from Fasttech, on my next order.... it's on my "wishlist" there already ...

Now that I have this working, I'll be attentive to the heat/temperature.

This is actually pretty cool !!! Gotta get a couple of the 18500s in that work, and then "convert" a couple more of these guys.

Thanks again! 

Later,
Jim


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## ohaya (Mar 19, 2013)

Hi,

BTW, does anyone have a good source for 18500s? I've ordered a couple to start, from Lighthound.com, but looking elsewhere, can't find much. I'd prefer protected 18500s, I think, over 900 mAh (more the better), and non-*fire (at this point)? Preferably shipped from the U.S.

Thanks,
Jim


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## RI Chevy (Mar 19, 2013)

I am working on finding a few good sources for 18500's myself. I am interested in the KeepPower 18500 protected cells. AW and Oveready sell them. Both 18500 IMR's and regular protected 18500's.


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## Poppy (Mar 19, 2013)

ohaya said:


> Hi,
> 
> This is just not making any sense at all !!
> 
> ...


Sorry, I miss-read this to say that the light DID turn on.

Glad you got it figured out.


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## ohaya (Mar 19, 2013)

Poppy said:


> Sorry, I miss-read this to say that the light DID turn on.
> 
> Glad you got it figured out.




Hi,

No problem . I am glad too !!

Jim


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## ohaya (Mar 19, 2013)

Hi,

BTW, I was out in the backyard tonight (pretty much moonless here, or maybe cloud covering moon) with the Lumen Master 250+ ( I just named it that ! ), and comparing it to one with the original 3xAAA and with another el-cheapo light I have, one of the Sipik clones from Amazon. 

I have to admit that I'm probably still pretty easy to impress, but I am truly amazed by the Lumen Master 250+ now !! 

It is very bright, and there's like no comparison between the either the original 3xAAA and the Sipik clone with the 250+

I also have a TF20, but was worried about trying that outside (we live in a fairly heavily populated area) .

Thanks to everybody, and esp. Up All Night!

Jim


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## ohaya (Mar 20, 2013)

Hi,

Learning Question: Circling around to the question of what is wrong with the 18500 battery that I originally tried, is the (mis-)behavior that I encountered, where the battery would show correct voltage when not loaded, but would not drive the flashlight, a sign of high internal resistance in this battery? I haven't actually measured the voltage under load (have DMM, but not the cables, etc. yet).

Thanks, 
Jim


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## ohaya (Mar 23, 2013)

Hi,

Encountered a problem. I received a new 18500 battery today, but it is an IMR 18500, and I didn't realize the implications of that (high current). I put it into the light, and it worked, so I left it on high to see what the runtime would be. After awhile, the light turned off, and would not turn on again, even with the original 3xAAA carrier.

Diagnosing the problem, it appears that the tailcap switch is now bad, e.g., if I switch in a known-good tailcap switch, then the light works again.

I was wondering if anyone has seen something like this, i.e., with an IMR battery, causing the tailcap switch to fail, possibly because the IMR battery supplies too much current for the switch to handle?

FYI, I've disassembled the tailcap switch, and I couldn't see any physical damage, so I'm not sure why it doesn't work.

Thanks,
Jim


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## RI Chevy (Mar 23, 2013)

You should have NO problems at all using the IMR. It can take a higher current draw, but I highly doubt that a 3-AAA light would draw enough to have an issue. It is not being driven hard enough. The IMR battery should be perfectly fine. It should not blow out your switch either. Probably just a bad switch.


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## Grmnracing (Mar 23, 2013)

I have been running the Lumen Master with a 14500 for a while now. I am very impressed with the light for being so inexpensive. Beam is not too clean, but very intense hotspot! Throw is pretty decent also. Heat management is surprising as well. All in all I am very impressed by this budget light.


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## ohaya (Mar 23, 2013)

Grmnracing said:


> I have been running the Lumen Master with a 14500 for a while now. I am very impressed with the light for being so inexpensive. Beam is not too clean, but very intense hotspot! Throw is pretty decent also. Heat management is surprising as well. All in all I am very impressed by this budget light.




Hi,

Thanks for letting me know. I started with a 14500, because I didn't have any 18500s at the time. I guess that if the 18500 works, that'd have longer runtime.

Did you have to use a magnet, like I've been doing, for the positive end of the battery?

What did you do for the size (diameter) difference? 

I'm currently/temporarily just using a strip of a paper towel, wrapped around the battery, but I have some of those convertors from Fasttech.

Jim


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## Grmnracing (Mar 23, 2013)

ohaya said:


> Hi,
> 
> Thanks for letting me know. I started with a 14500, because I didn't have any 18500s at the time. I guess that if the 18500 works, that'd have longer runtime.
> 
> ...



I'm using a rubber washer around the 14500 to keep it somewhat centered. And for now I'm using the top of the old aaa carrier to make contact. I'm looking for a good conductive washer or magnet to make the + connection. 


Steven


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## ohaya (Mar 23, 2013)

Grmnracing said:


> I'm using a rubber washer around the 14500 to keep it somewhat centered. And for now I'm using the top of the old aaa carrier to make contact. I'm looking for a good conductive washer or magnet to make the + connection.
> 
> 
> Steven



These are the magnets I've used, both work ok:

http://www.lighthound.com/Magnetic-Spacer-for-Charging-14-x-14_p_1047.html

http://www.lighthound.com/Magnetic-Spacer-for-Charging-CR2-or-14250-Battery_p_1048.html

For spacer, I have ordered these (will have to cut them, since they're meant for 18650):

https://www.fasttech.com/product/1219900

Jim


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## Grmnracing (Mar 23, 2013)

ohaya said:


> These are the magnets I've used, both work ok:
> 
> http://www.lighthound.com/Magnetic-Spacer-for-Charging-14-x-14_p_1047.html
> 
> ...



Thanks for the info. Those magnets are inexpensive. 


Steven


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## ohaya (Mar 23, 2013)

Grmnracing said:


> Thanks for the info. Those magnets are inexpensive.
> 
> 
> Steven




Hi,

Yes, I bought a bunch of both of them in a 2nd order (just received today).

Post back how they work, and I'll do the same when that convertor/spacer comes in.

Later,
Jim


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## ohaya (Mar 24, 2013)

Hi,

A little bit (but not a lot) off-topic, but I was able to replace the dead switch with the clicky from a $2.99 flashlight from a local Microcenter (http://microcenter.com/product/364967/Ultra_Bright_Flashlight), so it's working now, but no more modes, just on and off (I guess that might count as 2 modes to some people ).

Jim


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## Kick (Mar 24, 2013)

ohaya said:


> Hi,
> 
> A little bit (but not a lot) off-topic, but I was able to replace the dead switch with the clicky from a $2.99 flashlight from a local Microcenter (http://microcenter.com/product/364967/Ultra_Bright_Flashlight), so it's working now, but no more modes, just on and off (I guess that might count as 2 modes to some people ).
> 
> Jim



I just read the specs on that and it quoted 9,000 lumens, and it didn't even say _xxxxxFIRE_ on it. Gave me a good chuckle.


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## ohaya (Mar 25, 2013)

Kick said:


> I just read the specs on that and it quoted 9,000 lumens, and it didn't even say _xxxxxFIRE_ on it. Gave me a good chuckle.




A *LOT* of light in a little package, huh ?

Jim


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## texasPI (Mar 25, 2013)

Thanks for all the info. I've got three of the 200 lumen version. I might give your battery mod a try.


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## ohaya (Mar 25, 2013)

Hi,

It's actually not *MY* battery mod. 

When I started looking into this, there were various references to something like this working (people saying "I got it working", w/o saying what "it" was), but not much detail, so I figured I'd post info, in case anyone else wanted to do something like this.

Jim


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## pinetree89 (Mar 25, 2013)

hey guys, just wanted to add my 2 cents here on this thread. I don't know if this applies to the Techlite Lumenmaster mentioned in this thread, but on my version, the tailcap switch is not "dumb" switch like 99% of flashlights have. The tailcap switch appears to have some circuitry in it that assists with mode switching. Not entirely sure how it works as I haven't played with my example very much, but it's something to think about, especially when doing tests of shorting out the negative contact of the battery this circuit will be out of the mix.


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## ohaya (Mar 25, 2013)

pinetree89 said:


> hey guys, just wanted to add my 2 cents here on this thread. I don't know if this applies to the Techlite Lumenmaster mentioned in this thread, but on my version, the tailcap switch is not "dumb" switch like 99% of flashlights have. The tailcap switch appears to have some circuitry in it that assists with mode switching. Not entirely sure how it works as I haven't played with my example very much, but it's something to think about, especially when doing tests of shorting out the negative contact of the battery this circuit will be out of the mix.




Hi,

It's that way with the 250s that I have also, a small PCB in the tailcap, with a small chip (presumably an MCU) and bunch of resistors, and the physical switch. Also presumably, the path from the battery positive terminal to one side of the LED/emitter is direct (i.e., a "direct drive"?).

I've been told (elsewhere) that this is kind of an unusual design (not the direct drive part, but rather the PCB in the tailcap).

FYI, when I was testing this light, I did short the battery negative to the to the threads and it did light up, presumably in high mode. That was with the tailcap completely removed and not in the circuit.

Jim


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## ohaya (Mar 31, 2013)

Hi,

I finally got the adapter tubes from FastTech:

https://www.fasttech.com/p/1219900

I had to cut them in half (so I get 2 of them for each 1 !) but they seem to work, but are a little bit wider than the 18500s I have. However, once you put them into the light, and tighten the tailcap down, they're fine, with no rattling.

Jim


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## justle888 (Apr 28, 2013)

ohaya said:


> Hi,
> 
> I'm new here (been lurking for awhile), but I was wondering if anyone has replaced the 3xAAA carrier in one of the "Techlite Lumen Master 250" lights (from Costco)?
> 
> ...




Hi! I'am new here too! I've tried WY 18500 4000mAh 3.7V on Tech Lite Lumen Master also from Costco (in Taiwan), it works in all three mode normally. However, only turn on for about 1 min., the front part of the light got really hot. Is that ok? Or can it be danger and harmful to the light?

Thank you,

Justin


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## SilverFox (Apr 28, 2013)

Hello Justin,

Welcome to CPF.

One of the issues with replacing 3 Alkaline cells with 1 Li-Ion cell is that the Li-Ion cell will be able to hold a higher voltage and current under load. If the light has excellent thermal engineering and is able to dissipate the heat, there should be no problem. 

In general, warm is OK but HOT is not OK. 

Tom


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## RI Chevy (Apr 28, 2013)

RI Chevy said:


> I bought this sleeve to use with an 18500 to replace my 3-AAA carrier for use in my Solarforce L2i.
> 
> http://www.fasttech.com/products/0/10002938/1219900-3-x-aaa-to-1-x-18650-battery-converter
> 
> It is for an 18650, and it fits perfectly inside the host to replace the 3-AAA carrier, but just needs to be cut down for length to fit my specific purpose. I am awaiting 18500 batteries for the final fit. I will need to use a spacer or magnet. I'll report back when I do get it working. An 18650 will fit in a L2i, but the pring in either the drop in or the tailcap will need to be removed or shortened, or both. The host is plenty long enough. Just a work in progress for me. LOL



I finally got my Sanyo 18500 cells in. The fit with the above adapter is perfect, and the 18500 is a perfect fit (length wise) for the host. It is a great replacement mod for the 3-AAA carrier.


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