Battery Chemistry and Weight Comparison

[icefest]

The recent thread on lightweight torches has made me rethink my current setup.
I spent the evening researching battery chemistries and manufacturers.
The best primary battery for torches is currently the energizer lithium battery.

If you are interested, here are my results:




I also found the theoretical maximum energy densities

This is purely the reactive components, no casing, electrodes, or separators and perfectly stoichiometrically balanced.
Its also ignoring practical discharge curves.

If you want to know more I can highly recommend Linden’s Handbook of Batteries.
I really hope that lithium thionyl chloride cells improve their specific power, they are currently at double the capacity of LiFeS2 but cannot supply the current for a bright headlight. I don't recommend you try - they explode on high discharge.

If you see mistakes tell me and I will change them.

Sources:
AA

http://www.varta-microbattery.com/appli ... DS6205.PDF
http://data.energizer.com/PDFs/123.pdf
http://www.professional.duracell.com/do ... ra_123.pdf

Eneloop

http://www.eneloop.info/fileadmin/web_d ... _sheet.PDF

CR123a

http://data.energizer.com/PDFs/ea91.PDF
http://www.professional.duracell.com/do ... ium_AA.pdf

Technical Data

Lindens Handbook of Batteries, Fourth Edition 2011

[Orion]

...

CR123a

http://data.energizer.com/PDFs/ea91.PDF
http://www.professional.duracell.com/do ... ium_AA.pdf

I believe you have the links for the AA and CR123 batteries reversed.

A few comments.

First, your calculation of energy content is incorrect since it assumes a constant voltage.

Second, are you just reading the current capacity off of those graphs? I blew them up in photoshop and read different numbers than you.

For the Duracell AA bar graph I read ~3120 mAh (to 0.9 V @ 500 mA).
For the Duracell log/log graph I read ~5.70 h for 500 mA which translates into 2850 mAh (to 1.0 V @ 500 mA)
Note that these two are for different final voltages.

For Energizer ea91 I read ~5.86h from the graph --> 2930 mAh (to 1.0 V @ 500 mA).

Comparing apples to apples (discharge to 1.0 V) and given the coarse resolution of these graphs I'm not convinced there is a significant difference between the current capacity of these two batteries in this case. There is a ~10% difference in the typical weight but that's only 1.7g per battery.