If your iPhone 5 unit died and won’t come back on, or if it automatically powers itself on, and you are using a third-party cable to charge your handset, a battery replacement won’t solve your problem, because it is more serious than you thought.
UK repair company mendmyi (via iMore) has seen an influx of iPhone 5 units that had run perfectly until their battery completely drained, but after many charging attempts, users couldn’t get past 1% charge, or sometimes nothing but a blank screen.
At first glance, the guys at the repair company thought it was the battery, and they offered to replace it, but the problem persisted. That was the “yo!” moment, when they started investigating the issue and found out the damage that third-party charging cables can cause to iPhone 5 units.
As they have pointed out in a blog post, third-party chargers or USB leads do not regulate the voltage and current to a level protecting the iPhone unit, damaging the U2 IC as a result. This causes the aforementioned symptoms.
Charging your iPhone using a third party charger or USB lead that does not regulate this as much allows for larger variables in voltage and current, this then damages the U2 IC and can leave you with a seemingly dead iPhone 5.
Another common reason for this is also charging your iPhone 5 from the cigarette lighter of your car. This does not regulate the voltage as well as the original AC adapter as the power is coming from the alternator.
The U2 IC is pictured above and has the following tasks: It controls the charge to the battery, runs the power to the power/sleep button, and regulates the charging to the power IC that charges the iPhone 5.
In other words, if you want to protect your iPhone, use an original Apple-certified charger, and if you really need to charge your iPhone in your car, you should get a good-quality inverter, mendmyi recommends. By the way we have used various third party cables to charge our iPhone 5 and haven’t run into any issues, but your mileage may vary. We all take the risk when we buy third party accessories.