Which has more power overall CR123A or AA Lithium?

[matrixshaman]

I got caught off guard by a statement in another thread as I had always assumed CR123A Lithiums had more overall power than a AA Lithium. Do AA lithiums really have more capacity? Actual weight of a CR123A is heavier than a AA Lithium which would lead me to believe the overall power available is greater than in a AA Lithium. I know capacity is typically measured in mah but at 1.5 volt or closer to 1.6 volt is it actually more power overall. In other words power (which is a measure of total work done) in watts is voltage times current. So a typical 1550mah CR123A times actual 3.2 volts equals 4.960 watts or watt hours I believe. A Lithium AA might be a max 2900 mah times 1.6 volts which is 4.640 watts which is less power. I have actually never bothered to check into this and had just assumed the CR123A's had more power overall so I'm just throwing out some numbers here and may not have this right. BTW I weighed a Duracell and a Surefire CR123A on a digital postal scale and they both were 0.6 ounces each. An Energizer AA Lithium was 0.5 ounces. This may not even be relevant but was just part of my basis for assuming the CR123A's had more power.

 

[Lurveleven]

I remember seeing some test results from Silverfox on the AA lithiums, if I remember correctly he got 4.5Wh, but I don't remember at what current, I guess 1A .
The best CR123 only gives 3.2Wh at 1A and 4Wh at 0.5A. So it appears the AA lithiums are better.

Sigbjoern

 

[SilverFox]

Hello Matrixshaman,

Here are some numbers to consider...

At 1 amp draw, the Lithium AA has around 3.738 Watt Hours, with a mid point voltage of around 1.2 volts. A CR123 has around 3.167 Watt Hours, with a mid point voltage of around 2.2 volts.

The AA cells weighs around 15 g, and the CR123 weighs around 16.6 g.

Playing a little we come up with around 0.249 Watt Hours per gram for the AA cell, and around 0.190 Watt Hours per gram for the CR123 cell.

Tom

 

[2xTrinity]

I got caught off guard by a statement in another thread as I had always assumed CR123A Lithiums had more overall power than a AA Lithium. Do AA lithiums really have more capacity? Actual weight of a CR123A is heavier than a AA Lithium which would lead me to believe the overall power available is greater than in a AA Lithium. I know capacity is typically measured in mah but at 1.5 volt or closer to 1.6 volt is it actually more power overall. In other words power (which is a measure of total work done) in watts is voltage times current. So a typical 1550mah CR123A times actual 3.2 volts equals 4.960 watts or watt hours I believe. A Lithium AA might be a max 2900 mah times 1.6 volts which is 4.640 watts which is less power. I have actually never bothered to check into this and had just assumed the CR123A's had more power overall so I'm just throwing out some numbers here and may not have this right. BTW I weighed a Duracell and a Surefire CR123A on a digital postal scale and they both were 0.6 ounces each. An Energizer AA Lithium was 0.5 ounces. This may not even be relevant but was just part of my basis for assuming the CR123A's had more power

I think you're actually asking about energy capacity (watt-hours) as opposed to power (watts). CR123s will provide more power, mainly because their chemistry is higher voltage, that's why they're used for things like incandescent tactical flashlights.

At 1 amp draw, the Lithium AA has around 3.738 Watt Hours, with a mid point voltage of around 1.2 volts. A CR123 has around 3.167 Watt Hours, with a mid point voltage of around 2.2 volts.

The AA cells weighs around 15 g, and the CR123 weighs around 16.6 g.

Playing a little we come up with around 0.249 Watt Hours per gram for the AA cell, and around 0.190 Watt Hours per gram for the CR123 cell.

Using those figures then, the Lithum AA is delivering on average 1.2 watts, the CR123 is delivering 2.2 watts, but for less than half the runtime.

 

[xiaowenzu]

AA Lithium have higher current, the highest I've came across is 2800mah. CR123 have only 1700mah but higher voltage, about 3V vs 1.5

It all balance out in the end.

 

[robm]

AA Lithium have higher current, the highest I've came across is 2800mah. CR123 have only 1700mah but higher voltage, about 3V vs 1.5

Those figures are for capacity not for current.
2800mah = 2800ma for 1 hour, or 280ma for 10 hours at the rated voltage of the battery - 1.2V for most NiMH AA, 1.5 for an Alkaline AA
1700mah= 1700ma for 1 hour or 280ma for 6 hours at the rated voltage of the battery 3.7V for most RCR123A, 3.0 for a primary.

These are theoretical/ideal figures as actual capacity also varies with current, and is generally higher at lower current.

 

[matrixshaman]

Thanks everyone for the info and I think what 2xTrinity said explains how I got the impression CR123's had more 'umph' in them