A Changing World & A Variety of Uses
Natural disasters are just a question of time and rapidly increasing worldwide. Japan in 2007 suffered from several of these natural disasters including two typhoons and two major earthquakes in just one year. Christchurch in New Zealand still has not been rebuilt due to a shortage of skilled labour and supporting infrastructure. In 2007 flooding caused rockslides in Peru that nearly destroyed some of the Nazca geoglyphs which are situated in a desert region and attributed to climate change. To counter such challenges governments have planned disaster-response measures and risk management strategies to cope with these increasing events.
An outdoor power supply must supply power for extended periods of time, withstand operation conditions, be reliable, and be designed to be a light and compact form factor. Outdoor power systems are being purchased by the military not just for emergence operations but also as a backup or primary source of power for mobile platforms. Emergency services also use these devices to help them conduct rescue, extraction and support operations during natural disasters and events caused by region destabilisation. Private corporations and individuals are also starting to recognise the need to keep their operations running with uses relating to communications, operations and security systems in more challenging climates.
The uses of outdoor power supplies include supporting field hospitals, mobile vaccine centres, essential infrastructure, flood monitors and rescue teams. Rescue teams may use these to aid extraction and evacuation activities as well as providing warmth and powering communication systems such as mobile satellites, computers and mobile devices where possible.
In addition to disasters and emergencies out door power sources have uses for mobile teams supporting expeditions, veterinary teams, outdoor events and extreme sports coverage. In the US each year more people are becoming what is termed as ‘mobile homeless’, they sell their possessions and travel the US in RVs to reduce their outgoings. Each one of them needs effective robust power supplies to power fridges, heaters, cookers, as well as all-in-one portable solutions.
Backup Power Supplies
Communication centres and wireless hotspot systems typically use backup power supplies that run-on lead-acid batteries. While these are good when your energy usage is within the performance limits of the battery, they are a low energy density battery meaning you need larger and heavier systems for longer running times. Additionally, for systems that use longer lasting deep cycle batteries, you need to regularly check and maintain the battery. An alternative to lead-acid batteries are nickel metal-hydride (NiMH) batteries that can store up to three times more energy and also have charge-discharge cycles that can operate up to 55 ºC.
Battery Design
Outdoor power supply designs using NiMH technology are designed to protect against extreme weather unfortunately in high temperature environments a fanless design is still difficult to produce. The cabinet or battery case is typically coated with infra-red reflective material to reduce internal temperatures through exposure to radiant heat. In some conditions through integrating conductive techniques to diffuse internal temperature a fully sealed unit is possible and useful in military applications where fan noise should be avoided along with maintenance of wearable parts; the fan.
While battery cell design is fairly simple and easy to add to a new design, the technology driving their usage are critical to their success in terms of dependability, durability, efficiency and safety. An overcharge and over-discharge protection circuit for example is needed so the device does not suffer an early death, while some storage batteries may need a battery deterioration circuit to tell the user when maintenance is required.
The Future of Outdoor Power Supplies
Battery energy densities will be substantially improved through the use of nanomaterials for the battery cells allowing more charge to be stored and have much faster charge and discharge cycles. Currently however these are lab-based prototypes waiting for cost effective manufacturing processes to be designed and allow these to be integrated into the marketplace.
