Incorrect battery voltage

I am using the pm07 PMB. I have set it up in mission planner but voltage shows 0.82 even though I have a 14.8v battery

Them you probably have not set it up correctly.

If you do not provide information of what you did, we can not tell you what is wrong.

Asking the right question is half way to getting the answer you need.

I used the guide here:

Using HW ver Cuav v5/pixhawk4 makes it more accurate, but says 14.9v is 100% for a 4s battery. It should be 20%

The percentage is not related to the battery State-Of-Charge.
The percentage ALWAYS starts at 100% no matter what voltage the battery has, and gets decremented according to the battery_capacity parameter and the integral of the current consumed.

Ok. That makes sense. I got the voltage monitor to work, but current monitor is incorrect.