Mag-tac converted to 18650. Doesn’t work

Ameture60

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I’m not sure anyone has actually did it, so I gave it a go and drilled out the case to fit a 18650 with a 3/4 drill bit. Anyhoo the bulb lights up super dim and will not stay on.
so now you know it doesn’t work.
maybe I can change the LED/CRE?

46566188605_b7e723276d.jpg
 

grayjay70

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If I understand this correctly, the light originally used 2x CR123 cells in series each delivering 3v, so a total of 6V. Replacing these with a single 18650 only delivers a nominal voltage of 3.7v
The original driver board is likely not optimized for operating from the reduced voltage. You most likely can retain the original LED and get it to work with the 18650 Lion battery but should investigate replacing the driver board to work with the new available voltage.
 

Ameture60

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I’m pretty new and ignorant to all this high tec drivers and stuff. I’m going to be lerking for awhile.
big batteries and crazy bright lights seems like something I can get into.
 

Kestrel

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Hello Armeture60, :welcome:
Not bad at all for a first post, always happy to see new folks add to the knowledge base here.

Only speaking for myself, I would have guessed nearly-max output from one LiIon, which we usually see with the 2xCR123 Surefire & Malkoff lights (with their buck drivers), at least.
 

mmalive12

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Very surprised you would convert Magtac. Maglite is A JOKE these days. Especially the prices they charge. Same goes for Surefire. Much better lights out there that use 18650/CR123A more output and lower price.
 

Ameture60

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I was hoping it would have still worked.
Less voltage more amps shouldn’t be a problem for a 9800 MAH quickfire.
I guess I’ll take some measurements and see what I can fit in there.
It’s strange they made this thing with a extra large case that can fit a 18650. Usually metal is thin as possible must have been expensive and wasteful in production.
 

Ameture60

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We were blowing these out for 15 bucks at work. I was a dumb dumb and only bought one instead of the three we had.
 

Nephron44

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Very surprised you would convert Magtac. Maglite is A JOKE these days. Especially the prices they charge. Same goes for Surefire. Much better lights out there that use 18650/CR123A more output and lower price.

Maglite works for the population it is marketed for.

I haven’t yet had a Maglite fail on me while using it for its intended purpose. Even the Mini Mag incandescent I bought 6 years ago still works...I can’t even count how many times that thing has been through the wash, lost outside for days in all seasons, and dropped in ponds and puddles.

Yes I have better lights, and there are plenty of companies with better offerings, but Maglite just...works.
 

Lynx_Arc

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I was hoping it would have still worked.
Less voltage more amps shouldn’t be a problem for a 9800 MAH quickfire.
I guess I’ll take some measurements and see what I can fit in there.
It’s strange they made this thing with a extra large case that can fit a 18650. Usually metal is thin as possible must have been expensive and wasteful in production.
Amps aren't the problem less voltage usually means less output which also translates to less amps. If your 18650 is touted at 9800mah I would be concerned about the quality of it as the largest capacity 18650s don't go much beyond 3400mah.
 

Fireclaw18

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I think the highest capacity 18650 is 3400mAh. Not sure if there is a 3500 mAh yet.

Any 18650 cells with higher capacity numbers than that has false numbers written on it. In many cases those cells are low capacity 2000 mAh cheapies. In the most egregious cases, the cells are fake. Opening them up sometimes reveals a tiny LiPo cell with maybe 350 mAh capacity surrounded by "mystery powder". Probably plaster.

As far as why your mod didn't work I think the second post hit it on the head.

Most modern LED lights have a "driver" in them. The driver is a a circuit board that takes the power from the battery and sends it on to the LED. The driver contains a small computer (called an MCU) that is programmed with various different features. The MCU is what allows LED lights to have different brightness modes.

The driver is designed to accept 6v input, but a single 18650 is only 4.1v when full. You're probably getting almost no output because the light thinks your batteries are almost dead. Keep in mind the light does not know what batteries you are using... all it knows is the voltage is low for what it was designed to use (2x CR123).

Using two depleted CR123 cells in series can be dangerous. If the cells run all the way to empty, one cell can end up reverse-charging the other. In extreme cases this can cause the reverse-charged battery to explode. To prevent this, the flashlight designers probably programmed in low-voltage protection to automatically reduce output or even prevent the light from turning on when voltage gets too low. My guess is your 18650's voltage is just on the borderline. Enough to let the light run in low mode, but not enough to completely trigger the low voltage protection and turn off all output.
 
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Nimitz68

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I think the highest capacity 18650 is 3400mAh. Not sure if there is a 3500 mAh yet.

KeepPower makes both 3500mAh and 3600mAh protected 18650 cells as well as a high drain (10 A) 3500mAh IMR 18650. I have had very good luck with KeepPower cells.
 

alpg88

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maglite does not make it easy to get to driver board, let alone modify it, the whole conversions seems pointless to me, just get $15 convoy s2+, or s3, they will work with 18650, and will outperform mag-tac.
 
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Ameture60

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maglite does not make it easy to get to driver board, let alone modify it, the whole conversions seems pointless to me, just get $15 convoy s2+, or s3, they will work with 18650, and will outperform mag-tac.

Im so out of my league with this stuff but it’s like you just told me you can’t fit a V8 in a chevette, not that there is any point in doing that anymore, much better technology these days with Turbos or electric motors. Problem is I’ll be years on this project just learning how to make the brightest mag-tec:)
I guess a chevette with a big motor is still just a chevette. Lol
 

Ameture60

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It felt good to leave bad feedback on those quickfire cells. I’ve reached out to maglight to see if they will send me a driver and emitter from there rechargeable mag-tec. Pretty sure they will not help.
 

Fireclaw18

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KeepPower makes both 3500mAh and 3600mAh protected 18650 cells as well as a high drain (10 A) 3500mAh IMR 18650. I have had very good luck with KeepPower cells.

Good to know. I haven't paid much attention to the ultra high capacity 18650s since I always buy quality high-drain cells.

Modding flashlights is a fun hobby. It can be very satisfying taking a lemon light and turning it into a hot rod.

Sure it might be a lot easier to just buy a better light. Or buy a Convy and mod that. But it might be a lot more satisying to mod the Mag Tac and know that you have a unique light and probabaly nobody else has one quite like it.
 

alpg88

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Im so out of my league with this stuff but it’s like you just told me you can’t fit a V8 in a chevette, not that there is any point in doing that anymore, much better technology these days with Turbos or electric motors. Problem is I’ll be years on this project just learning how to make the brightest mag-tec:)
I guess a chevette with a big motor is still just a chevette. Lol


you seem to be more familiars with cars, so let me put it in car's language.

you are trying to shoehorn a v8 and awd into a civic, it is possible?, yes, but you will have to do prbly more work than it requires to build stock civic. yet it will be slower, nowhere near as reliable than a stock awd charger, but it sure will be a fun project.

you know all those things what you need to do with a car, it is similar with lights, you replace a power source, you need a different driver, you add more power (current) to the led, you need a led that will handle extra power, you add more powerful led, you need more cooling capacity to your light\better heatpath, or you'll fry your new led., you get a different led, you may need different optics.....
 
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snakebite

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picture not good enough to tell how that light is assembled.
it does look like the led board is like the pr dropins used in the c and d mags.
i have never had the opportunity to play with the magtac so not sure.
i have replaced the led in the older dropins.
the point about the low voltage lockout is probably correct but you were testing with known garbage batteries.
i would try with a known good cell before going further.
 

deRoland

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Maglite works for the population it is marketed for.

I haven’t yet had a Maglite fail on me while using it for its intended purpose. Even the Mini Mag incandescent I bought 6 years ago still works...I can’t even count how many times that thing has been through the wash, lost outside for days in all seasons, and dropped in ponds and puddles.

Yes I have better lights, and there are plenty of companies with better offerings, but Maglite just...works.
I've found enough battery workarounds and bulb upgrades to satisfy my needs for power....the price of the end product results in EDC's that will outlast me
 
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