I noticed a motion sensor light was weak so I assumed the batteries were dying and removed them. To make sure I was right, I tested the 4 D alkaline batteries. One was completely dead. One was on the brink (of death). And the other two were about 80% charged. This was the first and only time I'd ever changed the batteries for this light. So this has happened 1 out of 1 times, and NOT happened 0 out of 0 times, to answer a commenter's question.
I have noticed this with another electronic (a motion light) that uses 3 [I use rechargeable] AA batteries; they slide into the tube and touch end-to-end. The first one I pull out- at the anode end- is always very dead. The next one is pretty dead, and the last one (at the cathode end) in the rod-like light is always practically fully charged. This has happened EVERY time I've replaced the batteries in this device.
Why are these devices not draining the batteries equally? Is it because they are inferior products?
The two items are motion sensor lights; they have a PIR (infrared, I believe) sensor that detects movement, then they turn on. They turn off after a certain amount of time (that I swear varies but never measured).
The AA rechargeables are eneloop NiMH 1900mAh; all go into the light fully charged. The D batteries were all brand new, unused alkaline, Amazon Basics.