Does fast charger ruins my battery?

[AC Question]

Hi guys I'm using galaxy s5 with fast adaptive charger 9V-1.67A output. without fast charger my phone battery charges slowly.
should I use fast charger? plz reply

 

[Rukbat]

If you want a faster charge, sure.

"Fast charge" doesn't do anything bad to the battery. The S5 battery is 2.8 Ah (2800 mAh). The danger point is charging it at 2.8 Amps or more - which your charger (with only 1.67 Amps available) can't get close to. Even a 2 Amp charge would be safe.