@whoismoses whoismoses
Thanks for the data points.
Since my initial battery problem, and since I replaced the batteries with known good ones, I haven’t had the same problem anymore.
The first time, when I first received them brand new, I turned one of them on, and the batteries died before it was even 4 months in use.
This time around, it’s been 7 months, and it is still at 75%.
So, obviously, the problem was not in my head, but in the batteries that were in the device from the factory. 
Oh well, I won’t hold it against KEEN. Batteries go bad. The device itself appears to be working just fine, and NOT wasting battery power. Yay! 