Battery Life and Mr Beams


At Mr Beams, we know that battery power allows for more versatile and convenient installation of our lights. We also know that having to replace batteries often can be a pain. This is why we design and test all Mr Beams lights to last up to a full year on a single set of batteries, based on 8-10 daily activations. Nonetheless, battery life can vary depending on the use of your light, and we’re here to explain just why that is.

1. Why is one of my lights draining batteries faster than another?

It is difficult to specify the battery life on a motion-sensing, battery-powered light. It often depends on the way the light is used. For example, the Mr Beams Original Ceiling Light is built to last for over 3,200 activations on a fresh set of Alkaline C batteries. At Mr Beams, we design and test product for one-year battery life, at 8-10 activations per day.
Some installations will experience well over one year of battery life, as some customers report three years or more without replacing the original set of batteries. This is not uncommon for lights placed in attics, basements, sheds, etc. as these areas may be frequented less. Other installations, in heavily trafficked areas, may see a set of batteries drain over several months. Due to these varying results, we suggest referring to activation frequency, compared to our standard of 8-10 daily activations, to determine battery life expectations of your Mr Beams light.

To understand just what happens to a Mr Beams LED light when the battery gets low, see below for a typical AA battery discharge curve:


The Mr Beams Stick Anywhere Night Light uses four AA batteries. It will operate as advertised until an approximate 1V cutoff voltage per cell. Battery performance will vary, based on the rate of discharge needed to power a device, the temperature characteristics of the battery and the manufactured differences between batteries.
On a fresh set of batteries, a Stick Anywhere Night Light might not cross the cutoff voltage for 80 hours of ON time. However, this will vary pending any variations in battery performance. Keep in mind that the motion sensor will turn the light on only when needed and will automatically turn it off after 30 seconds of no motion.

2. Why is my light not as bright anymore?

When battery power falls below the cutoff voltage, two things may happen: 1) the LED will not be as bright. 2) the motion sensor may become unstable.

In the first case, the batteries have been drained to the point that they cannot continue to deliver the same amount of power, resulting in dimmer light output.

3. Why, and how, is my light staying ON when the battery is low?

When the batteries in your light have been drained to the point that the voltage to the motion sensor cannot be held in regulation, it may cause the motion sensor to false trigger. This can often cause a light to stay on continuously, after several months or a year of operating properly, and is an indication that the batteries should be replaced.

If you have questions or concerns about the battery life of your Mr Beams light, please reach out to us at so we can assist you in troubleshooting.