> Unless you can deliver multi-day battery, it's useless to provide anything more than all day battery

The battery time estimates are based on certain usage patterns, not 100% utilization of power-hungry apps. A battery that can last "36 hours" can offer more real-world usage per day than one that only lasts for 24.

Edit: Looks like the only estimates Apple provides any more are video playback hours, which is much more power-efficient than general app usage and internet browsing.

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giarc 5 days ago | parent [-]

But a phone with a 36 hour battery that still requires charging at night leaves the user/owner thinking "This is disappointing, I thought I could get 36 hours". As opposed to a user who has "all day charge" and charges at night thinks "This is what I bought and expect".

	▲	re 5 days ago \| parent [-]
		A user whose phone has "all day charge" that has to plug their phone in at 3pm because they used it too much in the morning would be, IMO, more disappointed. Ultimately "all day"/"36 hours" are marketing labels that are at best rough approximations of reality. Your original argument sounds like "if Apple says that the iPhone Air's 3,149 mAh lasts all day, then a 4,500 mAh battery is useless", but as any heavy phone user can attest, with high usage even a new iPhone battery will need to be charged midday, regardless of what Apple says, and an extra 50% battery capacity can be the difference between regularly needing to charge midday and not.