I am interested in carrying my eBike battery with me on my next flights. I am a bit at loss about which regulations applies (in the EU, but also intercontinental flights, EU-Asia and EU-America).
Let's say the battery is characterized by being a 36 V battery with a capacity of 480 W·h 12.9 A·h.
Does every airline have different rules?
It's not feasible to survey every single airline, but based on my intuition and confirmed by the sample I've checked, this battery is drastically too large (and therefore too dangerous) to bring on a passenger flight. The three airlines I checked: British Airways, Singapore Airlines and United all completely ban, from carry on and hold luggage, batteries over 160Wh. This isn't surprising since IATA makes this specific recommendation.
Batteries over 160Wh "Must be prepared and carried as cargo in accordance with the IATA Dangerous Goods Regulations". Hence they cannot come as passenger baggage.
https://www.iata.org/contentassets/6fea26dd84d24b26a7a1fd5788561d6e/passenger-lithium-battery.pdf
IATA's recommendations are binding on their members, meaning this rule will be enforced by most major airlines. Your battery is three times as big as this. It is not coming with you.
MJeffryes is correct with his answer, that for all practical purposes, you will not be able to fly with your e-bike battery.
Even if you didn't ask: A solution to that problem if you want to bring your e-bike and have a detachable battery, is to leave the battery at home and rent one at your destination. They are for sure not very wide spread and it will probably only work if you have a bike with a common battery type like Bosch or eZee, but there are at least some places where you can rent e-bike batteries. Google for 'e-bike battery rental' at the destinations you are planning to go and see if you find any.
