iPhone 6S Plus Battery Disfunction

I Would like to know if their is anyone out there who is experiencing the same issue that I am having with my IPhone 6S Plus. This is the Second phone that I have gotten from Apple since October. The first one I purchased and the one that I currently have both are and have given me the same issue. I think that there is a defect in Apple's Batteries. My battery will show a percentage and Bar at 100%. It will stay that way for the entire day even while in use for a couple of hours. The only time the percentage or bar may go down is when I reboot the IPhone. Even when I charge the phone the percentage will not change. For example, I charged my IPhone this morning at 43% for a couple of hours. When I came back to look at my IPhone it still said, 43% with a low battery bar. I rebooted the phone and it showed 100%. I had to do the same thing with my previous IPhone 6S Plus. I would like to know if anyone else is also experiencing this same issue. If so how did you finally resolve it. If it could not be resolved I think Apple needs to seriously look into this matter.