It says I have full battery when I don't

Kevin, first thing you want to try is a hard reset. Hold the sleep/wake button and the home button at the same time. Hold them until you see the screen go black.Keep holding them until the white Apple logo appears. When it does appear, you can let go. Your phone should now be reboot. If that does not help, try a restore through iTunes. Place the iPhone in DFU mode first.Connect the iPhone to your computer and launch iTunes, Turn the iPhone off (hold down the power button at the top of the iPhone). Hold down the sleep/power button and home button together for exactly 10 seconds, then release the power button only, continue to hold down the Home button. iTunes should pop up a message telling you an iPhone in recover mode has been detected. restore it from there, just remember to do that on the computer you normally sync to since you are going to lose your information. If that shows no results, make sure that your cable is working properly and your dock connector does not show any corrosion, bend or broken pins. If all that is okay, replace the new battery with the old one again. see if it shows the same error. It is possible that the circuit board on the new battery is faulty. If another new battery is going to give you the same error, it is possible that either your charging fuse is faulty or your power management IC LTC4088 has failed. You can try a reflow on that (last resort). Try the easy things first, one step at a time. Hope this helps, good luck.