I used some other charger for a couple days and now my phone's battery back up has gone very low, and it takes a lot of time to charge, and if I use the phone while charging the battery rather goes less. The charger also gets heated up and the battery too.
P.S. M using original charger now which came with the cell phone and i use blackberry z10 os 10.3
I have used different chargers and I have never noticed it taking longer. The battery always heats a little while charging and if you are using it at the same time, it will take much longer. That's the same no matter what type of phone you have.