sounds more like the wrong charger tbh, like with iphones and ipads where the chargers look identical but have different charge rates, plug the ipad one onto the phone and it seems to take about 20x longer to charge. Takes about 7 hours to charge an ipad and about 40 minutes for a phone
Have to say, something weird has happened to my old iphone, battery life seems much improved. before i used to get. about 8-10 hours of moderate use out of it at a push, now with similar use i'm only needing a charge once every 2 days providing i don't text much.