Question with Pixhawk PM02

Anyone had similar problem. My battery monitor fluctuate around 0.5v. Inderstand it fluctuate but shouldn’t the battery monitor average out the voltage to be presented?. AThat is a small issue but the main problem would be when every ilI plug in new battery, the monitor sometime will be off by 1volt. And always I have to update the correct voltage in the battery monitor. Is it because PM02 is a bad battery sensor? Or my sensor is spoilt? Is there a better more accurate sensor? How about Mauch?

Found my answer.