The main restrictions appear to deal with checked baggage. I usually carry-on all of my spare batteries.
That said, the actual TSA website uses some "equivilent lithium content" unit. Using that we can derive how much is in the CR123...
The limits are expressed in grams of "equivalent lithium content." 8 grams of equivalent lithium content is approximately 100 watt-hours. 25 grams is approximately 300 watt-hours:
A CR123 primary has 3.0v nominal voltage, and I would guess 1300mAH capacity. Which is equal to 3.9 watt-hours. I think what they mean by Lithium Metal batteries are Lithium Primaries, so you have a 2 gram limit PER CELL. 2 grams would be equivalent of approximately 25 watt-hours. So unless you had a 8000mAH 3.0v Lithium Primary, these new rules won't affect you. (Note, there are apparently some Lithium Primary C cells that would have more than 2 grams, but note that these are primaries, aka non-rechargeable. I don't think they're popular at CPF.)
Now let's have a look at Lithium-Ion batteries. Apparently as long as these have less than 8 grams of Lithium Content you aren't affected. What capacity is this for 3.7v Lithium-Ions? 27,000mAH for a 3.7v Lithium-Ion is equivalent to 8 grams. My 3.7v AW C cells are only 12.21 watt hours, or about 1 gram each. Unless I had an 8x Lithium-C light (or RC car), I wouldn't bump into the 8 gram limit. But since each cell is below the 8 gram limit,
technically I could have as many of those floating around as I like the way I read it.
Let's just hope we don't run into screeners who don't know about batteries trying to confiscate our large cells. I fly on the 4th, so I guess I'll see first hand, though to be honest they've never even blinked at my camera bag (with lots of Lithium batteries, electronics, flashlights, flashes, amateur radio equipment, etc).
