From my understanding it varies from airline to airline.
I’m looking at the Air Canada page that has details for example which can be found here.
But I’m not sure certain what it means.
Can I have a portable power bank that’s 160W? If I bring that could I also bring on a laptop and a Steam Deck?
It seems like you can bring 15 devices theoretically.
I think you’d have to be a camera crew or something for them to apply the 15 device/battery rule.
I frequently fly for work domestic and international, thats 2 giant laptops, my switch, 2 phones, 2 controllers, power bank etc… I look insane unpacking, and it takes a lot of baskets because the bigger devices should be in individual baskets. It’s also a bit stressful looking after all your stuff.
Most of the battery laws are for checked-in luggage, I bring all this in my 2 carry-on and have no trouble (I dont put the controllers in my checked bag just in case).