NLee the Engineer says:

A well-designed motion sensor light with amazing battery life I picked up this at a local warehouse Club purely out of curiosity. I fully expect it to be a battery hog since it says “wireless motion sensor” on the package. Surprisingly, the battery life is far better than I imagined. (More on that later)When I first tested this unit, I almost thought it was defective because the motion sensor does not seem to work. The LED lights won’t turn on no matter how much I wave in front of the sensor. Finally, I noticed there is a photo-sensitive resistor (light sensor) on the side of the unit. It turns out that in AUTO mode, the LED lights will only turn on when it is dark outside AND there is motion detected. (Note to self: read the instruction manual first!)The motion sensor is quite sensitive and can detect slight movement even from 10-12 ft away. Once on, the lights will remain on as long as there is motion detected, or else it will turn off after 60 seconds of non-activity. This is a very logical design once I understood how it works. (Again: read the manual!)I then proceeded to measure the battery consumption:- When the LEDs are on, the unit consumes between 160mA (when powered by three fresh alkaline AA cells) and 110mA (when powered by three )- In standby (AUTO) mode: the unit consumes between 2.2mA (alkaline cells) and 1.7mA (NiMH cells)What the above mean is that: if I put three 2000mAh eneloop cells in there, the unit can remain in standby mode for about 1000 hours, or about 40 days. If I use alkaline cells, it can probably remain in standby for up to 2 months. This is because under very light load, an alkaline AA cell can deliver about 50% more energy than eneloop AA cell.Of course, the actual battery life depends on how frequently the LED lights come on. Assuming the lights are on for 15 minutes every day, then based on my calculation, a set of eneloop cells should power this unit for at least 30 days. That is not bad at all.Finally, although this is called an “under cabinet” light, it can be mounted anywhere – either horizontally or vertically. I have one placed in my living room near the staircase. At night, it automatical lights up whenever I come down the stairs, so I never have to search for the light switch in the dark again. For that I’m happy.[Aside]It turns out that the motion sensor is based on passive infrared, rather than active RF signal. The term “Wireless” on the package is actually referring to the fact that this is a battery-operated LED light – so you don’t need to run wires to the light.

B. Smith "wrigley12" says:

You will need rechargeable batteries. Got these at Costco for a decent price. We did not want to wire the typical under cabinet lights and thought these would be a good option. We have liked the lights and they provide good light output with full powered batteries. Once the batteries start declining in strength so do the lights.Main issues:- The photocell sensor is not sensitive enough and cannot really be adjusted. Our kitchen does not get a lot of light, but enough to not have to turn on the our ceiling lights during the day. Thus, these led lights come on all the time and drains the batteries faster.- Not that energy efficient if you go through batteries every couple of weeks. I now have bought rechargeable batteries and charger and do not care as much as I did when I was burning through regular batteries.Main benefits:- Easy to install and change batteries when installed.- Provides good strong light with full strength batteries. Light is blueish however. Takes some getting used to.Overall, the lights are worth buying at a decent price. I think we paid $20 at Costco and I wouldn’t pay more than that. Make sure you have rechargeable batteries and charger though.