Originally Posted by
fastair
Check the drill, carry the batteries. (2) separate regulators impact these rules for different reasons.
TSA=drill is a potential weapon/way to modify aircraft. (Security)
DoT=battery is a fire hazard and should be in with you as you will notice it overheating (thermal runaway) in the cabin much faster than if it were in the pit. (Safety)
http://www.ntsb.gov/investigations/fulltext/hzb0501.htm
Yup. Also, if a battery does go into runaway it's much easier to fight a fire in the cabin than in the luggage compartment.
As for shipping them, many shippers will have restrictions on shipping them as well, especially if that shipper uses comercial aircraft in their operation. (see the link, many of the incidents occured on FedEx/other shipping companies aircraft.) Primary (non-rechargable) are prohibited period, and rechargable ones are restricted based on capacity and where they are stored.
Yup. Every few years I order replacement batteries for UPSes. They arrive in a box marked that it can't be shipped by air.