Fly the Unfriendly Skies
Dec 29--Remember all those news stories about exploding batteries and laptops that caught fire? Well, apparently so does the Department of Transportation, which has decided to do something about it. To wit, starting with the new year here in the US, we have new travel regulations to follow while flying in the US.
Short version: in your checked luggage, all lithium or lithium-ion batteries need to be in the device they power and that device needs to be turned off. Any spare batteries you might wish to bring need to be in your carry-on luggage. There are limits to capacities that can be carried, but only laptop batteries come close to those limits--Nikon camera batteries are well within the limits. And remember this only applies to lithium-based batteries.
However, there's going to be a lot of hassle and confusion on this one, I think. The limits are expressed in grams (which is grossly translated into watt hours), which is not how most of these batteries are marked. Make sure you know how to calculate watt hours (amp hours * voltage; an EN-EL3e battery is 1500mAh and 7.4 volts, so it is 11 watt hours, well under the limits). Second, make sure that the terminals for any extra battery are covered, either by using the cover supplied by the maker, taping over the terminals, or by putting each battery in a separate plastic bag. The rules are also confusing over the number of spare batteries you can carry. It appears that you can carry many under 100-watt hour spare batteries, but only two over 100-watt hour spares. I'm sure there's going to be confusion on this, too. Finally, make sure you know which of your batteries are lithium-based and which are not. And yes, it will be the TSA that is doing the enforcing.
Unfortunately, this new directive intersects with other flying issues: specifically, the weight of your carry-on. More and more the airlines are realizing that heavy carry-ons impact their fuel consumption, and gas prices are one of their biggest costs. Thus, you find more places weighing carry-ons, and in some places, the limits are draconian (the typical limit is 10kg (22 pounds), but some are more limiting than that. A couple of extra EN-EL4a and laptop batteries in your carry-on pushes up the poundage quite quickly.
And yes, this was a last minute change (though apparently brewing behind the scenes for quite some time as the DOT played with blowing up batteries in different ways).