Is there lithium rechargeable batteries in AA size?

[picard]

Is there lithium rechargeable batteries in AA size?
I am looking for lithium rechargeable in same voltage as NiMH AA but it should have greater Amp than NiMH.

I can't recall the type of top of my head.

 

[matrixshaman]

All Lithium rechargeable batteries use a chemistry that produces 3.6 volts or some of the newer ones are roughly 3 volts. AFAIK none of the rechargeable Lithium chemistries are anywhere close to 1.2 or 1.5 volts.

 

[mudman cj]

Rechargeable lithium batteries (lithium ion) have a cell voltage of 3.6V nominally. Lithium primaries have a nominal voltage of 1.7V and greater capacity than Nimh, but they are not rechargeable.

 

[picard]

oh crap. How can I use lithium rechargeable for my headlamp? It uses 3 AA NiMH at the moment.

Does this mean that lithium rechargeable batteries will fry my head lamp if I use it?

 

[Marduke]

What's wrong with the NiMH? I think you're under the impression that they have vastly inferior energy, but in reality they actually have less than 14500 Li-Ion

NiMH
1.2v x 2700mAh = 3.24 watt hours

Li-Ion (AW's protected 14500)
3.7v x 750mAh = 2.775 watt hours

 

[LEDninja]

You can use 1 lithium battery and 2 spacers.
3 lithium batteries will fry your headlamp.

oh crap. How can I use lithium rechargeable for my headlamp? It uses 3 AA NiMH at the moment.

Does this mean that lithium rechargeable batteries will fry my head lamp if I use it?

Marduke is almost right. You can use 3xNiMH or 1x14500.
NiMH
3x1.2v x 2700mAh = 9.72 watt hours
Li-Ion (AW's protected 14500)
1x3.7v x 750mAh = 2.775 watt hours

What's wrong with the NiMH? I think you're under the impression that they have vastly inferior energy, but in reality they actually have less than 14500 Li-Ion

NiMH
1.2v x 2700mAh = 3.24 watt hours

Li-Ion (AW's protected 14500)
3.7v x 750mAh = 2.775 watt hours

The main advantage of 14500 over AA is mainly in 1xAA torches. Modern LEDs require 3.4 to 3.6V to light up.
A 14500 has 3.6V and can direct drive the LED at 1000mA to give 200 lumens.
An AA is 1.2V and needs an expensive amplifier to boost the voltage to 3.6V. Also with few exceptions these amplifiers top out at 350mA giving only 90 lumens max.
With 3xAA your headlamp already has 3.6V. So it can direct drive the LED just like a lithium, no amplifier required.
Just swapping a lithium for your AA cells would not increase the brightness. To do that you have to:
1) Upgrade the LED,
2) Upgrade the heatsink to get rid of the extra heat generated,
3) Tweak the dropping resistor to give the right amount of current.
As headlamps are usually not easily mod-able I think you should just let the headlamp be.

 

[Fallingwater]

oh crap. How can I use lithium rechargeable for my headlamp? It uses 3 AA NiMH at the moment.
Does this mean that lithium rechargeable batteries will fry my head lamp if I use it?

If you put LiIon 14500 cells in place of the NiMH ones it now uses you will fry it.

However, three NiMH cells can almost always be swapped out with one LiIon, or a parallel arrangement of LiIons. So you could, in theory, rewire the 3AA holder to a parallel connection and use three protected 14500 cells.

The big question is: why? NiMH cells aren't ancient history, they are still very good for many applications.

 

[rizky_p]

well i am using 9xNimh in my M@g85 instead of granade size Lithium D size bomb

 

[mdocod]

As already stated there would be no reason to switch your headlamp to AA size li-ion cells, as they would have less energy than the NIMH that is already in there.... now, if you wanted to do some MAJOR modifications, you could run a single 18650 size cell and achieve about the same energy as 3xNIMH cells with less self discharge and less weight, but running 3 14500(AA size) cells in place of 3 NIMH AA cells will actually reduce your available power.

If you are having problems with self-discharge, May I suggest you pick up some LSD cells. There are some applications where switching to li-ion has advantages, your application really isn't one of them.