Have an iPhone 5 that won't seem to charge past 1% or boot up at all anymore after the battery was completely depleted? It seems that you aren't alone. According to UK repair company mendmyi, who has seen an influx of iPhone 5's with this particular issue, the problem is a prime example of why you shouldn't use cheap cables to charge your iPhone.
While we all hear the warnings about using cheap chargers and USB cables, we all know that not everyone will listen. In this particular case, cheap chargers and cables are damaging the U2 IC chip that sits on the logic board of the iPhone 5. This particular chip controls the charge to the battery, the sleep/wake button, and certain USB functions. A damaged U2 IC chip ends up causing the iPhone 5 to not turn back on once it's depleted. A replacement battery brings the iPhone 5 back to life, but once that battery depleted, you'll be stuck in the same position again.
Owner of mendmyi, Riki Baker, has this to say about what is causing the issue -
Charging your iPhone using a third party charger or USB lead that does not regulate well 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 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. If you need to charge our iPhone or any electrical equipment in your car, we would recommend a good quality inverter with your original charger and USB lead.
If you have an iPhone 5 that seems to be dead or won't charge past 1% and you're using a non-OEM charger or cord that isn't from Apple, this is most likely your problem. mendmyi is currently offering repairs to fix the U2 IC chip but if you aren't within the UK, you can check with other local repair companies or an Apple Store to see what your options are.
Hit the link below to read mendmyi's explanation of the problem as well as detailed photos showing a working U2 IC chip and a damaged one.