Reading Battery Level if Vcc is constant 5v

Situation: Have a PowerBoost 500 that is pushing a constant 5v to Vcc regardless of battery voltage condition. The PB500 monitors it's own battery level and lights an LED when the LIPO hits 3.3v indicating charging required. It also supplies a Low Battery Output (LBO) that is either HIGH or LOW.

Question: Can I tap off the battery to A1 and measure the voltage there as though I were measuring any other voltage (say a TMP36) so I can write my own routine to display a % indicator on an SPI OLED? As opposed to just indicating BATTERY LOW from the LBO to a Digital Input?

(If there is a solution that I failed to find, please link me up! Thanks)

Jessica

Yes, but battery voltage does not tell you much about the % charge.

MorganS:
Yes, but battery voltage does not tell you much about the % charge.

True. Researching it does appear that SoC is really only across 0.05v on a LIPO. I also researched Coulomb Counting with Arduino, and discovered addons that do what i require. Thanks for your reply! It made me Google something I hadn't thought about.

On the PowerBoost 500, is the input GND the same as the output GND?

larryd:
On the PowerBoost 500, is the input GND the same as the output GND?

Yes. The grounds are not isolated.