At current count, I believe at least one bazillion people have emailed me about the new safety rules for lithium batteries on planes.  Why such interest? Perhaps the new ruling by the Department of Transportation (DOT) ) is a wee bit confusing, yes, a wee bit.  

It seems airline passengers are no longer allowed to pack loose lithium batteries in their checked luggage. The new regulation, designed to reduce the risk of lithium battery fires, continues to allow lithium batteries in checked baggage if installed in an electronic device. When uninstalled and loose, lithium batteries must be placed in carry-on luggage in a plastic bag.

Here comes the confusing part: only two extended-life spare rechargeable lithium batteries with lithium content weighing between 8 grams and 25 grams are allowed. Because almost all consumer-type lithium metal batteries contain less than 2 grams of lithium, this particular rule is really directed toward batteries used for commercial applications, not business travelers.

Damon Darling in The New York Times article  Lithium Battery Ban? Check Again quoted security expert Bruce Schneier as saying,  “Near as I can tell, this affects pretty much no one except audio/visual professionals.” Good news indeed as my A/V cache consists of an iPod and Brownie camera.  

If you're not sure about your battery classification, visit the DOT's online information page which features a battery acceptance matrix: Traveling Safely With Batteries and Battery-Powered Devices.