Is it bad to fast charge your battery?

[mpedroza]

I've been fast charging my battery for over a year now and I was not aware this is a feature you could disable. Now I'm trying to charge it normally (with the original charger as always) and it says it's charging slow and to use the original charger and it's taking up to 3 or 4 hours to charge. Is this normal? Did I ruin my battery?

 

[IAmSixNine]

Its possible the data port has gunk in it or the original cable is damaged.

As far as your battery goes. It will loos a small percentage of capacity over a year.
What is really bad on lithium batteries is excessive heat (which rapid charging produces) ((especially if your rapid charging and using your device)) and extreme low voltage. Running the battery down and not charging it for a while.

 

[Rukbat]

3-4 hours is normal for a slow charge. A "fast" charge is still well under a 1C charge (charging at the rated capacity of the battery), so it's safe.