Every winter, we get a few questions about how well Mr. Beams Wireless LED Lights will work in very cold environments. One attribute of LEDs that makes them ideal for outdoor applications is their extended temperature range. LED lights can be very durable in cold environments; however, every component that makes up the LED battery-powered light needs to have an extended temperature range.
Taking this into consideration Mr. Beams Wireless LED lights have an operating temperature range of -4 degrees F to 140 degrees F at a relative humidity of 90% (-20 degrees C to 60 degrees C at a relative humidity of 90%). We do this by selecting every component in our products to meet or exceed this temperature range.
To make sure a product can operate over the extreme temperature range, only batteries with an extended temperature range can be used. Energizer, Duracell, Panasonic and other battery manufacturers offer an industrial temperature range battery. Let’s take the example of an Energizer Industrial D Size Alkaline battery. The datasheet for this battery on the Energizer website is http://data.energizer.com/PDFs/EN95.pdf. It has a temperature range of 0 degrees F to 130 degrees F (-18 degrees C to 55 degrees C). The specification for the battery sets the operating temperature of the Mr. Beams MB360 battery-powered LED Security Spotlight with this battery installed. That is still a pretty good operating temperature.
One important point though is that light output will decrease at the very low temperatures. Why? The efficiency of the LED actually improves at colder temperatures (i.e. more light is generated for the amount of power consumed from the battery) so that cannot be the reason. It turns out that the battery performance is considerably reduced at the lower temperatures. Looking at this technical bulletin on the Energizer website at http://data.energizer.com/PDFs/BatteryIR.pdf, you can see in Figure 2 that the internal resistance of the battery increases at the lower temperature. The higher internal resistance of the battery hurts the battery performance. It impacts the performance of the light to more than offset the increase in LED performance therefore overall the light output is decreased. We estimate that the lumen output of any wireless LED light at lower temperatures may drop as much as 20% based on the degradation in performance of the battery in cold weather.
The bottom line is that Mr Beams Wireless LED lights have been installed and working at low temperatures for years. They are a great solution for outdoor lighting in cold weather environments. If you have a cold weather lighting application, we hope you will consider the Mr Beams LED lights. For more information on why Mr. Beams Wireless LED lights are well designed for outdoor lighting applications, please visit our blog entry “How to Choose the Best Outdoor Lighting” or visit our website at www.mrbeams.com.