It's unclear to me what the official requirements are. For example this is from the TSA's site:
"Devices containing lithium metal or lithium ion batteries should be carried in carry-on baggage. Most other consumer electronic devices containing batteries are allowed in carry-on and checked baggage."
Taken literally, this is of course widely ignored. There are also various requirements around spare batteries that do include capacity limits.
"Devices containing lithium metal or lithium ion batteries should be carried in carry-on baggage. Most other consumer electronic devices containing batteries are allowed in carry-on and checked baggage."
Taken literally, this is of course widely ignored. There are also various requirements around spare batteries that do include capacity limits.