# Is it possible to replace 3AAA battery holders with a lithium battery?



## mccririck (Feb 10, 2012)

Anyone know if you can turn a 3AAA flashlight into something that can accept a better battery?


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## Bozzlite (Feb 10, 2012)

What is the overall length and width of the battery pack? In millimeters if possible. You might be able to replace it with a li-ion, if the dimensions are right.


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## mccririck (Feb 10, 2012)

53mm long, 20mm wide


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## Bozzlite (Feb 10, 2012)

Well, the closest li-ion battery size that I know of would be an 18500. It would be a couple mm thinner and a couple mm shorter. I'm sure your flashlight has a positive contact at the top center, but probably doesn't have one at the bottom. That would be a problem with just dropping in an 18500 battery, even with a spacer. 

So if you have a bottom spring or contact, it might work. The voltage would not be a problem, just figuring out how to make the connections. 

You are gonna need a high drain battery like an AW IMR 18500. At least that's what I'm thinking. I know the 3AAA Dorcy I had sucked down the batteries pretty quickly. It put out a lot of light tho. 

Good luck, hope that is at least a starting point.


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## mccririck (Feb 10, 2012)

It has a positive contact at the top and a negative at the bottom. There's a spring on the tail cap and another spring at the top end of the flashlight.


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## mccririck (Feb 10, 2012)

It has a positive contact at the top and a negative at the bottom. There's a spring on the tail cap and another spring at the top end of the flashlight.


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## gerald_clark (Feb 10, 2012)

Many 3AAA flashlights will also take an unprotected 18650. 
You may need to add a cardboard sleeve to increase the diameter.
I have 5 different ones sitting right here.


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## mccririck (Feb 11, 2012)

Which 18650 would you recommend? Is Weiss a good brand? Why do you say unprotected?


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## Bozzlite (Feb 11, 2012)

mccririck said:


> Which 18650 would you recommend? Is Weiss a good brand? Why do you say unprotected?



I think by unprotected he means safer chemistry like the AW IMR 18650. The IMR batteries are sometimes a couple of millimeters shorter than the circuit protected batteries.


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## mccririck (Feb 11, 2012)

65mm is going to be 1.2cm too long though, so the 18650 is out I think.


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## gerald_clark (Feb 11, 2012)

It all depends on the flashlight. You will often see the same flashlight being sold as 3-AAA and 18650.


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## ScaryFatKidGT (Feb 12, 2012)

I have heard they take 18500's


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