My cell phone is starting to charge very very slowly when plugged in. When I unplug it - the power percentage drops rapidly. It started happening when I first got the phone, and then I changed it over to an older style Samsung charger - which my phone took the charge no problem. Now my cell phone is starting to do it again. The only charge that it now seems to take and keep is from my car charger. Someone please help. Do I need to bring my phone in for repairs?