voltage and chargers

i dont know about that, but i do know the blackberry chargers are the fricking bomb. i bought 2 off ebay for like $4 each and they'll take my nexus 5 from 5% charge to 95% in under an hour.

i saw a post on xda about them and they're for real. doesn't seem to hurt the phone to charge that fast.

Cable voltage rating doesn't matter. That just means the cable can accept up to 30V. You need to look at the voltage output of your charger. That cannot be above 5V.

The current is based on the device. Some devices will want to draw roughly 2A to charge, others 1A. You can use a 2A charger to charge the 1A device but charging a 2A device on 1A charger gives a slow charge and could eventually cause the charger to fail.

My S4 stock charger will do the same. Weird because the S3 charger is much slower