Power Shield reporting wrong battery voltage

[splendid2k]

I'm using a R4 moteino with an R3 power shield. My batteries finally arrived today from China so very excited to have free roam on my sensor locations!

I'm using 3.7v lipo battery for power and my multi-meter reports a voltage of 3.9v currently.

I'm using the below code to get the battery voltage but it is returning a value of around 8.6?

Code Select Expand

int batteryReading = analogRead(A7);
theData.battV = ((float)batteryReading * 3.3 * 9)/(1023*2.976);

Do I need to tweak some parameters or is something else possibly wrong?