We performed a real-world test with a singly hosued mouse training on FR1 for 5 days.  Here is the battery discharge curve, indicating that FED3 can last about 5 days of continuous use on a charge.  This can probably be improved by optimizing sleep modes further (it currently sleeps whenever a pellet is in the well), but it seems good enough for our purposes.

He took 345 pellets during this time, also note that pellets taken are higher at night.