Winter is in full swing! While it's sunny and unseasonably warm out here in Seattle, it's still cold around many parts of the US and Canada. A common phone call this time of year is about sensors under performing. The first reaction is that the sensor is broken or defective but most commonly it's a battery and power problem.
"Cold temperature increases the internal resistance and diminishes the capacity. Batteries that would provide 100 percent capacity at 27°C (80°F) will typically deliver only 50 percent at –18°C (0°F). The capacity decrease is linear with temperature. The capacity decrease is momentary and the level of decline depends on the battery chemistry."-Battery University.
What does this means for sensor users? Your battery will have trouble drawing up enough power to supply the sensor if it is too cold. In the Summer, your batteries will be pushing out at top gear, but also drawing up more energy than you may suspect, weakening them faster.
Testing your sensor is best at room temperature. If you suspect your sensor of under performing, bring it inside and get a fresh set of batteries. Test the sensor with the new batteries, letting the old ones warm up. We usually keep a small radio or base station around to test batteries in, and your base station can be used as a test for those older batteries, once they've warmed up.
It can be frustrating having a sensor that doesn't perform when you need it to. Keep in mind the placement of your sensor and the temperature. Try to keep the sensor in sunlight whenever possible during the Winter, giving the sensor a better chance of retaining some warmth. Oppositely, try and shade the sensor in the Summer, saving your battery life from over expenditure. We recommend changing the batteries every 6 months, but before you throw away those old ones before summer, give 'em a test at room temperature. You may have some good life left in them.