Basically if I charge my iPhone 7 (or Apple Watch) to 100% using my wall charger or from my MacBook Air's USB the charge lasts MUCH longer than if I charge from my USB power bank. I've tried multiple power banks and have the same results every time. Same goes for my Apple Watch.

A friend suggested that perhaps it never enters the slow/ trickle charge stage of charging and just does "fast" charging all the way to 100%. If this is true, wouldn't that be an iOS or iPhone hardware issue?

Anyone else experience or notice this?

Also, my power bank has a 5W 1A output and a 5W 2.1A output. Both seem to do the same.

UPDATE: Okay, so far I've done a few tests and am noticing that charging using a 5W source works great and the problem happens when I charge using a 10W source.

  • 3
    How many times have you tested this to prove your hypothesis? And, how do you test it? Also, have you tried using an app such as Battery Life on your iPhone or installing coconut Battery on your MacBook Air to use it to report back on your iPhone's battery? It'd be interesting to see if you get the same results after charging with your USB power bank as you do with your wall charger etc. – Monomeeth May 9 '17 at 4:46
  • @Monomeeth I'm currently testing this hypothesis. It will take some time to finish. I'm testing the Power bank 5W (5V 1A) port, Power bank 10W (5V 2.1A) port, Apple Wall Charger 12W (5.2V 2.4A), and the Apple Wall Charger 5W (5V 1A). I'll note how long it takes to get from 0% to 80% and then to 100%. I'm also testing how long it takes to discharge back to 0% with my regular use. I think after running the tests a few times my "regular use" will average out and what will be left are the details I'm looking for. – teewuane May 9 '17 at 19:14
  • I mainly asked the question here to see if anyone else had conducted tests like this and to see if there was some common knowledge about power banks and charging that I'm missing :) – teewuane May 9 '17 at 19:15

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