If you bought an extra battery for your cell phone, take note: New rules from the Transportation and Security Administration that take effect on January 1 ban travelers from carrying loose lithium batteries in checked baggage, CNET News reports.

Passengers are allowed to pack "two spare batteries in their carry-on bag, as long as they're in clear plastic baggies."

This doesn't apply to batteries that are already installed in gadgets, such as the one in your cell phone or laptop. This is if you decide to bring along an extra one to power your laptop throughout a cross country flight, or to let you charge one cell phone battery in the hotel while using another one during the day.

New security rules for batteries on planes [CNET News]