Lead batteries have long been at the heart of emergency electrical lighting. Because the simple technology delivers affordable, dependable solutions. The earliest designs used lead-acid batteries and incandescent light bulbs to illuminate exit signs and stairwells during blackouts. Nowadays, of course we have more advanced ways to shed light in emergencies.
Lead-Acid Installations Once Shed Light in Emergencies
Advanced emergency planning evolved, as city trading stores burgeoned into modern skyscrapers. Feeling ones way to the exit door was no longer acceptable, nor stumbling down long staircases in the dark.
Huge lead-acid battery banks stored 120-volt DC charges. Remember, Edison’s light bulbs took power from the national grid, and that was all we had.
The switching technology must have seemed like a miracle at the time. Relays and transistors sensed the moment the mains supply failed, and quickly turned on emergency lights at strategic points. While these may have shed light in emergencies, the best they could manage was a dull glow. If there was smoke present, they were almost no good at all.
The Revolutionary Arrival of Calcium Batteries and LED’s
While early lead-acid batteries were cheap and reliable, they were relatively high maintenance despite having antimony in their plates.
Replacing this with calcium resisted corrosion, and most importantly gave off less gas. This reduced battery size to the point where batteries fitted neatly into light ballasts.
But the real game changer has proved to be the light-emitting devices themselves. LED lights containing diode clusters shed brilliantly bright light, that we can aim, rotate, and focus too. Their batteries are small enough to fit into the bases of the fittings. Tiny transformers convert mains and battery current to low voltages required by devices that shed light in emergencies nowadays. The image is of the International Space Station while the crew sleeps.
Related
Emergency Lighting = Instant Battery Power
Go Green LED Lights Saving The Locals
Preview Image: Emergency Light
