Power draw in usage vs battery capacity?
I've never really looked at it like that, but I guess we should take the least generous values from both:
Pure Capacity:
iPhone XR: 2,942 mAh
iPhone SE: 1,624 mAh
Draw:
iPhone XR: "Up to 15 hours", so 196,134 mAh of draw if we take the best case for the iPhone XR.
iPhone SE: 12-13 Hrs on Internet (so, LTE, according to apple) that's roughly 129,92 mAh
; while the capacities are wildly different I don't see the SE being so far behind.
If you can get real power draw numbers you can make your own conclusion. I suspect Apple expects a certain about of idle time (which has been optimised for on the later generations).
So I would guess around 28% of its battery when an XR is at 40%.
https://www.anandtech.com/show/10285/the-iphone-se-review/3
24% longer on wifi web browsing. Worse on the graphics benchmark, but only because the framerate is higher (smaller screen resolution) which keeps the CPU from idling as much.
Makes you wonder what the performance of a modern small iPhone could be like.