http://www.gsmarena.com/battery-test.php3
GSM Arena Endurance Rating
Apple iPhone 4s = 45 hrs
Web - 6:56
Video - 9:24
Apple iPhone 5 = 51 hrs
Web - 9:56
Video - 10:12
Apple iPhone 5c = 52 hrs
Web - 9:05
Video - 7:41
Apple iPhone 5s = 54 hrs
Web - 9:58
Video - 10:31
Apple iPhone 6 = 61 hrs
Web - 10:29
Video - 9:24
Apple iPhone 6 Plus = 79 hrs
Web - 9:05
Video - 11:15
Apple iPhone 6s = 62 hrs
Web - 12:27
Video - 10:46
Apple iPhone 6s Plus = 85 hrs
Web - 11:51
Video - 13:57
Apple iPhone SE = 73 hrs
Web - 12:55
Video - 14:17
_
Huawei Nexus 6P - 74 hrs
Web - 8:35
Video - 9:59
LG Nexus 5X = 60 hrs
Web - 8:32
Video - 6:25
Motorola Nexus 6 = 70 hrs
Web - 7:54
Video - 10:01
LG Nexus 5 = 38 hrs
Web - 4:45
Video - 5:01
LG Nexus 4 = 32 hrs
Web = 4:34
Video = 4:55
_
GSM Arena tends to skew the overall scores with talk time, so I pay attention more to the web and video playback scores since that correlates more to screen on time. For my money, the iPhone SE scores the best with SOT among all iPhones. Just add the browsing and video playback time and divide the number by 2. Or just look at phones that gives you a triple-double in all three areas and specifically a double-double or double-dozen (12+ hrs web/video).
Huawei Nexus 6P has surprisingly poor results with web at 8.5 hrs. Their Mate 8 excelled at it with over 17 hrs. Nexus 6 also scored fairly average at only 7:54 hrs for web. The S7 edge (either version) has fantastic video results at 20+ and nearly 17 for the US model. Most iPhones other than the 4s and 5c excelled in both web and video stamina. So yeah, stick to iPhone if you can only depend on a single device.
Some of these results don't always reflect real life though. My HTC One M7 never gave me 10 hrs with web or video. Had the AT&T model which was known to be worse with stamina. More like 5 & 7. My Mom's iPhone 6 Plus tends to drain faster than her 5. She gets mostly 6 hrs instead of 8 from her previous iPhone 5. I believe SE ranks the highest in battery life even with its 73h rating which scored less than the Plus models of 79 and 85. 13 & 12 are great results for the SE.
My Phones
Xiaomi Mi 3 = 66 hrs
Web - 8:04
Video - 9:28
Microsoft Lumia 640 = 76 hrs
Web - 10:23
Video - 9:43
Motorola Moto E (2nd gen) = 82 hrs
Web - 12:42
Video - 13:04
I believe that those results are fairly accurate with my phones. Moto E2 tends to give me the best results with over 10 hrs SOT every single time even if I stream or download videos. The 12 & 13 hr stats isn't far fetched. Only has to power a "4.5/540p with an ample 2390 mAh which is near my Lumia's 2500 mAh size which has to power "5/720p. And 2500 mAh is ample enough for that size/res unlike the HTC One M7, Xperia Z, and Nexus 5 packing smaller to power 1080p.
My LG G3 Beat was not tested with GSM Arena but is similar to the G2 mini (76 hrs) or maybe between the Lumia and Moto (78-80 hr range). Standby on it is fantastic and I took a screenshot of it reaching 11:05 once doing mostly web and occasional streaming with 40 hrs of idle time to boot. I charge it every 3-5 days. Was the champion with its 2540 mAh before the Moto E2 arrived. Battery results tends to matter to me less these days since I just rotate them anytime they reach 30-40% and three of them have a minimum 70 hr rating.
One phone's weakness is another phone's strengths and vice-versa.
One M7, Galaxy S3, Nexus 4, Xperia Z
^ I can't believe 3-3.5 years ago I wanted a Nexus 4 and Xperia Z. The Nexus 4 was on my wishlist for awhile. Now I am grateful I never did as well as never getting the Xperia ZR, Moto X (2013), and Huawei Ascend P6. I can't believe the Snapdragon 410 found in budget phones today like my cheap Moto E2 or ZTE Zmax 2 outperforms the Snapdragon S4 Pro.
It felt like yesterday people were going crazy for a Nexus 4 for $299! Now we have a sub-$100 Moto E2 and ZTE Zmax that outperforms the Nexus 4 and Xperia in performance and battery life. The Moto G4 is also arriving soon which looks like a Nexus 4 but far better. LOL at 32h rating for Nexus 4. Sub-5 hrs for web and video. First gen Galaxy Note also scores shockingly bad for web at 3.5 hrs.
Entry phones now are faster than most 2010-2013 flagships. By 2019, we will have FHD & QHD phones in the sub-$100 market that will outperform some current flagships of today. This is the main reason why I got turned off by flagships as of late. Where is their value when you know none of them will defeat Father Time as seen from my lost interest with many top phones from 2-3 years ago.