Monitor Battery Charge Level

[ElectricalWannabe]

Apologies if I've overlooked a thread discussing this before, but I'm having troubles seeing how people are keeping track of how much energy their discharging batteries have left. I see that the adafruit battery has inbuilt protection for overcharging and overuse (shuts off at 3V). The adafruit powerboost also has an onboard LED that turns on at critically low charge (3.2V). These are useful, but it looks like together they only tell you if your battery is between 3.2V and 3V. Is it possible to use something like this Lipo fuel gauge https://www.sparkfun.com/products/10617 wired to the teensy being used for the buttons to monitor the remaining charge? Is this even necessary, or am I missing the point of some other component?
Thanks

[shitwing]

It has been discussed on this thread: http://sudomod.com/forum/viewtopic.php?f=8&t=175

Doesn't really look like anyone came to a conclusion on the subject though.