I have referred https://github.com/craic/pi_power to create UPS. As per author if LiPo voltage drops down to 3.7V it wont be able to power RPI and thats why he suggested to keep 3.75V as safe low battery cutoff voltage. With 3.75V cutoff i am getting only 7.15 hours of run-time from 4400mAh LiPo!!!
As per powerboost documentation
I also read multiple post on different forum's where there is range of 3.2V to 3.7V for low battery safe shutdown.LBO - not a leveraged buy out! this is the Low Battery Output. By default it is pulled high to BAT but when the charger detects a low voltage (under 3.2V) the pin will drop down to 0V. You can use this to signal when its time to shut down or alert the user that the battery is low. There is also a red LED connected to this pin.
Considering my use( average 130 mAh and max 300mAh) what should be safe low battery cutoff voltage?