Delete comment from: Ken Shirriff's blog
Hi Ken, awesome experiment. I have been interested for a while to understand how a USB charger of a given rating (e.g. 2.1 A) charges different devices. The motivator is that while Apple says you can use an iPad charger for iPad/iPhone/iPod, which makes sense, using my iPad charger on my iPod for 2 weeks in Mexico completely destroyed its battery's ability to hold charge.
So I opened up an Apple 30-pin cable, cut just the red wire and ran it through an ammeter. The iPad that claimed to be at 65% was only drawing 100 mA. I don't know what kind of feedback control iPads and Apple chargers use to determine when they're in CC/CV modes, but it seems like it should still be charging all out when it's still at 65%.
Any thoughts?
Thanks,
Matt
Nov 27, 2012, 5:06:13 PM
Posted to Apple iPhone charger teardown: quality in a tiny expensive package