For use in semi-covered areas, e.g. at the last exit, on loading ramps in logistics or in car parks, luminaires for emergency lighting must not only be waterproof (IP65) but must also be able to withstand large temperature fluctuations without difficulty.
In times of LEDs as a light source, low temperatures are no longer a problem, unlike fluorescent lamps. In order to make the battery temperature resistant as well, we use
a special heating element that does not let the battery temperature drop below 5°C. The battery is not damaged and a reliable function of the luminaire down to -15°C is guaranteed. The heating function also ensures that the battery lasts longer and maintenance costs are lower.
he following temperature/time diagram documents the practical suitability of the constructive approach. Even below -15°C the battery temperature does not drop below 7°C. This corresponds to the operating conditions of our batteries. Overheating is not significantly detectable. After switching off the temperature switch, the condition “ambient temperature = battery temperature” is reached after approx. 20 minutes.
The short heating phase after switching the bi-metal switch is clearly visible, with maximum approx. 13°C around 13:22 o’clock at approx. -7°C chamber temperature. Then the battery temperature of approx. 7°C at -15°C chamber temperature is set.