The man looks as if someone just told him the Earth is flat. Yet it's actually quite simple: Everything with a battery that isn't permanently installed belongs in carry-on luggage. Period. End of story.
I just did the math myself: My entire electronic equipment adds up to 142 watt-hours. MacBook Air, Sony cameras with spare batteries, smartphone, DJI Osmo Pocket — all together under the magical limit of 160 watt-hours. Calculating this is like cooking with Weight Watchers, except here you don't gain weight — you just might miss your flight.
The airlines have developed a complicated system that's about as transparent as a tax return. Built-in batteries under 160 Wh can go anywhere, but removable spare batteries only in carry-on, e-cigarettes must always go up top (thankfully I'm a non-smoker), and if you show up with an e-skateboard, you might as well turn around and go home.
The calculations remind me of those Japanese computer games where you have to stack items efficiently in a too-small space. Except here the game over screen means you get to throw your 100-euro power bank in the trash. So I just leave it at home.
Though I strongly suspect I'm the only one who bothers to add up their watt-hours. I'm probably once again the fool who's adding up batteries while power banks are merrily traveling in checked baggage under the airplane seats.
Sometimes I dread thinking about how many of these little energy storage devices are actually spinning their forbidden rounds down there, and just hope they behave themselves and don't get too hot uninvited.
Wait, let me calculate quickly: An Airbus A321 Neo has 39 rows with 6 seats - oh right, rows 7 and 13 don't exist because of the superstitious faction. So 37 rows, making about 216 passengers.
Everyone has a smartphone (60 Wh), every second person has a MacBook (50 Wh), two photo nuts like me (another 40 Wh), plus what feels like 40 children's tablets with flashing cases and nerve-wracking games (25 Wh each) — adds up to... Let's see... roughly... about 18,000 watt-hours.
Whew. That's equivalent to the energy of about 9,000 Red Bulls.