I managed to make (as always in a electronic shop) YT full brightness test myself with both S8 and S8+.  My results were: 14 %/h -S8\ 11-12%/h - S8+. I tested my P2 once again and I received results 7,5-8%\h. When we calculate how many mAh there is from each battery all of these phones have consumed about 400mAh. Also for the first time I played some games on my P2: Asphalt 8/Extreme, Real Racing 3, CSR Racing etc. with full brightness, NFC, BT, localisation, mobile data turned on and....with 5 hours of playing around I lost about 11%/h... It seems that killing P2 under 8,5- 9h is pretty much impossible, I think the camera app also uses the same amount of energy, maybe up to 12% (full brightness photographing or video recording). What's more, I tested the P2 speaker against pretty much every mid-range and flagship phone available officially in Poland. Only phones which are almost as loud or as loud (In my opinion the P2 was never "the quieter one") as the P2 were  Huawei Mate 9 &
9 Pro (but surprisingly IMO normal Mate 9 was louder), iPhone 7 and I liked how the front-facing Moto Z (and Z Play) sounded but still they were a little bit quieter. P2's speaker was noticeably louder and more impressive in terms of quality than the majority mono speakers: the new LG G6, all Samsungs, Asus Zenfone 3, Redmi Note 4, Huawei's P9 or P10 (also Lite versions) or Sony stereo speakers (but those never were the loudest on the market). However, somehow any of those sounded as "non-digital" as the P2, even Mate's and iPhone's. I was surprised that always my P2 was "different", especially while listening to known for me Youtuber's voices P2 is making -for a smartphone obviously- a damn good job.  It seems that GSMArena really wasn't​ lying about the P2 with "It's one of the better single-speaker setups we've encountered lately."