Effective 1 January 2008, lithium-ion and lithium-metal batteries face new restrictions for carriage on a passenger aircraft.
• Lithium batteries may not be placed in checked baggage unless installed in/on the powered device (thus, no spares in checked luggage).
• Unlimited numbers of small Li-ion batteries may be carried on as spares, but only 2 spares above 8 grams Li content (about 100 watt-hour capacity) may be carried, the total amount not to exceed 25g (about 300 watt-hours). It appears that these “two large batteries” are in addition to the multiple small batteries you can carry, but read http://safetravel.dot.gov/whats_new_batteries.html to be sure.
• Lithium-metal batteries face even tougher restrictions: Li-metal batteries over 2g are not permitted at all, either attached to devices or carried as spares. Fortunately, the most common Li-metal batteries we deal with are the little button cells that maintain camera clocks and memories; these are OK.
The FAA has a good writeup with a handy chart.
Most pro-level batteries are rated in watt-hours, but prosumer camcorder batteries are rated in amp-hours (Ah) or milliamp-hours (mAh). Conversion factors:
– Watt-hours = battery voltage x amp-hour rating
– Watt-hours = battery voltage x milliamp-hours / 1000
For example, a Specialized Communications high-capacity Li-ion battery for an HVX200 is rated at 7.2v, 6000mAh. That translates to 43.2 Wh. The stock Sony BP-U30 battery for a PMW-EX1 is 14.4v, 1.95Ah, or 28.8 Wh (the “U30” being a battery with a nominal 30 Wh rating, apparently), while the high-capacity BP-U60 is twice as much.
It’s unlikely that any of the prosumer batteries pack more than 100 Wh, so you’re safe carrying on a whole mess of them–but be sure to cover their terminals to prevent short-circuits. I put a bit of gaffer tape over the terminals, or pack each battery in its own plastic bag.
V-Mount and A-B batteries will likely run into the over-8-gram, over-100Wh category, and big ones may exceed the 25 gram limit.
See this news report for a rather graphic example of why these rules make sense. Unlike most of the “security theatre” the TSA has foisted upon us, these FAA rules really are related to safety of flight: lithium batteries contain their own oxidizers, thus if they catch fire they will not self-extinguish, and are almost impossible to stop from burning once they start. If they’re in the cargo compartment, they’ll burn unobserved, and set fire to other things. In the passenger cabin, at least, you’ll notice it when your bag starts smoking, and the batteries can be dumped out onto the cabin floor so they won’t set other things alight.
See http://safetravel.dot.gov/whats_new_batteries.html for more details, and Anton Bauer has details on their batteries.