Problems with PID controll using quad encoders

I have notice every time I plug or unplug a new battery the current PID settings don’t work anymore. We’re using the encoder via the talonSRX and the library of CANTalon. Do you recommend stop using PID control or and using percentage instead.

Are you resetting the encoder values?
Also is there a large difference in the voltage of the battery? Like before it was 8 and now it is 12?

Could you post your code or explain, in detail, how you are setting the PID values? (How are you setting the PID values via the RoboRIO web dashboard or in code?) Which settings don’t work anymore (can you describe the problem in more detail)?