International regulations say that you can have in carry-on maximum two 100Wh-160Wh spare lithium-ion batteries, subject to approval by the airline.
There is no such requirement for batteries not exceeding 100 Wh.
Does anyone have any experience how such approval of >100 Wh power banks work in practice? Has anyone ever been rejected to carry a 100-160 Wh power bank?
Theoretically, to be sure, its probably best to request a letter from the airline in writing, before buying the ticket, with a permission to carry a specific power bank, to show the paper at security control in case of problems.
But in practice, is it usually a non-issue, and you can just show up with a 100-160 Wh power bank and go through security without problems? Or are there any stories of people having their 100Wh-160Wh power banks rejected? I am asking in the light of the PLUG Travel Indiegogo campaign of a 42000 mAh/151 Wh battery pack.