Originally Posted by TimPotter
I just got back from the Nats, and all my bags were checked, on both flights, but they did not confiscate anything. By reading this article it looks like I was in breach of regualtions by putting 5 packs, not connected to devices in my checked bag.
Update: March 18, 2009
The DOT has a whole slew of tips for traveling with batteries, in addition to the more general battery guidelines that clear up some of the questions being asked in the comments below. Plus, it looks like there has been a change in the number of batteries allowed for personal use. Here are some key points:
Carry spare batteries in the original packaging. If that's not possible, pack the batteries in such a way that the ends of the batteries won't touch one another, and batteries won't come in contact with any other metal objects (coins, keys, jewelry, etc.)
For safe transport of loose batteries, you can also put tape over the battery's contacts (at either end).
Make sure not to pack batteries in such a way as to crush or puncture them, as it can cause a short-circuit.
For personal use, there is no restriction on the number of batteries you can carry on, though there are restrictions for larger lithium ion and lithium metal batteries. Here's the DOT quote: "For personal use, there is generally no restriction on the number of spare batteries allowed in carry-on baggage. This is the case for cell phone batteries, "hearing aid" button cells, and AA batteries [or] AAA batteries available in retail stores, as well as almost all standard laptop computer batteries."