Does Anyone Make a 22500 Li-ion or emoli?

Something like a 22500 would be almost a direct replacement for those 3xAAA battery holders in so many LED lights, and would likely have more than twice the capacity of the AAA's.

Does anybody make one?

As far as I know 18500s are still your best bet. You can use 18500s which have about 60% more capacity (up to 1500mAh) than 3s NiMH cells (900mAh). The next "size" up that I've seen is 26500, which is too big to replace 3xAAA.

22500 or 22550 would be a really great idea for all these 3xAAA lights, too bad they don't exist

A word of warning from someone who has replaced 3AAA with 18500 and sometimes 18650, many times.

I have burned out several emitters doing this. A combination of slightly higher loaded voltage & less resistance is ofen just too much.

pay attention to what lctorana is saying here as it's very important!!!

what I like to do is measure current across tailcap on the regular 3AAA pack, then compare it to the current with the li-ion. If it's only slightly higher, it'll probably be fine, especially if it's like a 1W emitter or something (like going from ~300mA to say, 450mA)... They can usually handle that.

multi-5mm lights are more sensitive to the voltage difference and can easily double or more their running current on a li-ion cell. This is likely to cause premature failure.

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You can always install a resistor (or replace an existing resistor) to compensate. Or better yet, install a current regulator.

Eric

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PS: another option on some of them, would be to see if a sub-C (NIMH) cell would fit. They are 23440 size... This would leave 6mm of space to install a boost regulator

Just found this cell at Kaidomain:
http://www.kaidomain.com/ProductDetails.aspx?ProductId=5142
May be a bit to long for some 3xAAA lights

mdocod said:

...it'll probably be fine, especially if it's like a 1W emitter... ...They can usually handle that.

multi-5mm lights are more sensitive to the voltage difference and can easily double or more their running current on a li-ion cell. This is likely to cause premature failure.

Click to expand...

Just for the record, my own experience has been the opposite. I have found the multi-5mm LEDs to be robust and survive the battery swap, but have experienced failures with 1W emitters, such as the Zhongsheng ZS20HBA, when subjected to 18500 or 18650 power.