The current GoPiGo (Sept 2020) comes with an 8 x AA cell battery holder which when used with quality NiMH cells supplies 1900 or 2500 mAh of power, with the voltage starting around 12v and ending around 7.6-7.8 volts. Panasonic Eneloop 1900mAh cells will provide at least 750 cycles and 2500mAh cells will provide around 250 cycles. The 1900 cells provide a maximum “on time” of about 6 hours and about 1.5 to 2 hours “wander with distance sensor only”, while the 2500 cells provide a max of 8.5 h “think time” and 2 to 2.5 h of wandering, when using a Raspberry Pi 3B.
Using the PiCam and OpenCV onboard has to be very carefully managed to avoid temperature throttling, and can significantly affect “on time.”
Using AA size NiMH cells as the power source enables the native GoPiGo volts() function to report the current battery voltage and allows an estimation of remaining time before needing to recharge.
Lithium chemistry batteries are becoming pervasive and are the current Dexter Industries recommended solution for a ROS/LIDAR based GoPiGo:
Those packs should provide 1.5 hours or 3 hrs of LIDAR + distance sensor GoPiGo wandering with off board computational support that ROS allows.
Edit: The solution does enable the GoPiGo to monitor the voltage because it provides unregulated 9-12.6 volts.
(Due to my GoPiGo robot running 24/7 and “unattended”, I am avoiding joining the “LiPo Powered Life.” The usual recommendations to “always charge LiPo batteries in a fire-safe bag” and “never charge LiPo cells unattended” are just too scary to risk it.)