It's not "fake" power, but some third party charging docks, as well as a lot of non-Apple PCs don't provide enough CURRENT to charge a battery properly. They may meet the USB power specs for voltage, but don't have enough umph behind the volts.
Another issue is the device which provides too much voltage... there was at least one third-party speaker set which would actually burnout iPhones. We found out the hard way at the store, when customers began popping their iphones in to test the speakers out, only to have their iphone "popped" instead.
Try charging your iPhone using the wall charger and cable it originally came with. go straight into the wall, don't use a power strip, etc... Try this for several charge cycles (a week or so) and see if the battery life improves.