Getting down and dirty with airport lighting usually means digging trenches for cables and creating a power infrastructure with generators, but Carmanah has come up with an easy-to-install, solar-powered, LED alternative.
"The technology is designed to operate virtually anywhere in the world," says Allister Wilmott, aviation development manager for Carmanah. The lighting system consists of easy-to-install, individual lights that absorb sunlight during the day, without wires. At night the LEDs are bright without distortion while wearing Night Vision Goggles (NVGs).
Currently used at military bases worldwide, these lights work from the desert of Bagram Airbase in Afghanistan to the extreme elevation of Elmendorf Air Force Base in Alaska at 62 degrees North and have dramatically improved operations at USAF bases. A response to Carmanah from personnel at Bagram quotes "... the pilots love the lights and we have had no complaints. They work extremely well, even with NVGs on. Your lights are all we really have on the runway and taxiways ... perfect for this environment where our power is not reliable and failures are common ... your runway lights are 100 percent reliable — unlike our commercial or generator power ..."
"I would say that the biggest advantage of our technology for military installations is its ease of installation and maintenance free operation at expedited airfields," says Wilmott. This feature makes the lights indispensable in places like Iraq and Kuwait where there isn't always access to conventional power. For example, a 560-light expedited airfield in Bagram was installed and operational in less than a day.
The lights can be installed in minutes, either on mounting stakes or frangible couplings or in some cases, directly bolted to concrete or plywood. They then stay in the field, maintenance-free for up to five years. If the base closes, just pick the lights back up and take them with you. "You're eliminating power ... cabling ... wiring ... operating costs ... engineering drawings ... [and] maintenance," says Wilmott.
The success of Carmanah lights has come from combining two technologies, solar power and light emitting diodes, to create a self-contained unit, explains Wilmott. Each unit is its own power supply, light and control. A polycarbonate lens covers each unit which also has a polymer doming on top and polymer on the bottom to give the light a tough external protection. "You can actually take [the] lights and throw them off the pavement or concrete and they won't break," says Wilmott, who once made a sale because his superior lights could handle being the football for some Navy clients.
Being individual, small, lightweight units speeds shipping and decreases freight. Wilmott recalls that when Ali Al Salem Air Base needed airfield lights right before Operation Iraqi Freedom broke out Carmanah was able to send 300 lights in less than seven business days. And while conventional systems take five pallets on a C-130 to bring an airfield system in, Carmanah's Portable Solar Airfield Lighting System (PSLS), takes only one or two pallets. "And you're getting rid of your generators and your fuel requirements," adds Wilmott.
The solar panel uses a lead-acid gel pack with starved electrolytes, which unlike a car battery, allows it to work in extremely cold temperatures, as well as in extremely hot. The battery will also never deep-cycle, or use more than the top 10 percent of its battery capacity. This allows five to eight years of maintenance-free operation, unlike cell phones or rechargeable flashlights.
In a place like Elmendorf Alaska the light needs to stay on for 20 hours, so when the sun comes up the solar panel makes a direct connection to the battery. The opposite happens in Iraq. Since there is heat and sun for 16 to 17 hours a day, the battery goes into a trickle charge to prevent overcharging. This operation is controlled by a power management system, an individual microprocessor in each light that controls intensity, output, voltage and interacts with the environment.
Automatic Light Control
In addition to the battery, the power management system also runs what Carmanah calls Automatic Light Control (ALC). In normal conditions the light operates at 100 percent intensity based on acceptable levels of sunlight and temperature, but in less than ideal environments, like Elmendorf, the light adjusts.
As December approaches in cold climates the ALC recognizes a decrease in sunlight as well as a drop in the voltage due to colder temperatures. Because the system will not use more than 10 percent of its battery and cannot get more power from the sun, it adapts by dropping its intensity. "The light output decreases, but the autonomy increases keeping the light on through the whole night, all winter long," explains Wilmott. Without ALC, the light would keep running at 100 percent and fail after 70 or 80 hours, but with ALC you can get 150 hours of light output with absolutely no sun at all.
For guaranteed autonomy the lights at Elmendorf are reduced manually to 50 percent intensity. "That's only a reduction in candela output of .04, so you get a slightly dimmer light ... [but also] roughly 400 hours of autonomy," says Wilmott. If the lights were not changed manually, the ALC would control this function, slowly altering the intensity output to adjust for less sunlight. "It will stay at 100 percent for a while and then it will stay at 75," says Wilmott. The changes are gradual to avoid the light "see-sawing" up and down.
The LED (Light Emitting Diodes) technology is very efficient as most of the output is light, not heat, and the light is focused without the need for additional optical components. This focused light makes them NVG compatible. They do not create the blooming or halo effect common with incandescent fixtures. The light is produced by applying a small electrical current through a silicon "chip" made of a special blend of crystals. Colored light is produced by different combinations of crystal materials. LEDs are also extremely durable.
Solar LED technology is brand new to the aviation industry, but with customer comments like "I think Carmanah's solar-powered lighting products will change the way people look at airfield lighting ... everyone is amazed at the brightness of the lights ...," and "Thanks for sending us a quality light and I look forward to doing business with you again ...," it's no wonder Carmanah has more than 7,000 units at 55 different Air Bases worldwide and has positioned itself as the GSA (General Services Administration) sole provider for self-contained, solar LED aviation lighting solutions for the U.S. Air Force, U.S. Army, U.S. Marines, Air National Guard and Air Reserves.