How Does a Battery Powered Generator Work?
For mission-critical applications like life-sustaining medical equipment or networked telephone systems, power failure is not an option. For that reason, many businesses and a growing number of home-based handymen are turning to generators that provide some or all of their electricity from a standing battery bank.
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Generator Design
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A battery-powered generator works by using the electricity stored in a battery to provide alternative power to one or more systems that normally work off the main power grid. Because the energy is stored and is immediately available, a battery generator can provide instant cut-over for a failed circuit, with no time spent finding fuel or turning the generator on.
Power Inversion
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Most commercial and residential homes are wired to receive alternating current (AC) power. This type of energy features a power stream where the polarity (direction of electron flow) shifts directions rapidly. Batteries, by contrast, release direct current (DC) power--the same power system in automobiles and battery-powered toys and games. In order to translate DC into AC, you must use an "inverter," but be aware that inverters are not perfectly efficient so some power will be lost in the DC/AC conversion process. Never try to use a device that requires AC on a DC circuit since it can severely damage the device.
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Recharging the Battery
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Batteries are rated for the maximum capacity of energy they can store, and as devices draw power from them, they begin to run down. A temporary battery-powered generator may be sufficient to provide electricity until a gas-powered generator kicks in. However, for many residential and small-business customers, it makes no sense to have two generators, so they will often use a battery-powered generator that includes a small gasoline or diesel engine. This engine turns an alternator that generates current that recharges the batteries. With an external power source keeping the batteries topped off, it is possible to keep a battery-powered generator running continuously. In fact, some businesses run their internal phone systems exclusively off a battery bank, and they keep that bank charged from the main--turning on an external power source only after the main fails during an emergency.
Local Grid Access
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A certified electrician should manage the wiring to add any generator onto a local power circuit. In general, the electrician will bring a power line from the generator to a transformer adjacent to the main circuit breaker. In the event of a power failure, a person simply needs to flip a circuit to bring in the electricity from the battery-powered generator. In more sophisticated setups, certain circuits within a house or building that require continuous power are fed separately through an auxiliary breaker panel; this panel alone is powered by the battery generator, with all other circuits remaining dead until main power is restored. It is possible to purchase transformers that automatically sense a fall-off in the main incoming circuit and will automatically switch between the main and the generator with no manual intervention.
Maintenance and Safety
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A battery-powered generator is safe and easy to maintain. In addition to standard precautions that apply to any kind of generator (e.g., ensuring that wires can handle the flow of current, and keeping the unit safe from children and pets), owners should inspect the batteries every six months. There are several different battery technologies on the market; some can last many years with monthly maintenance, while others require less maintenance but more frequent substitution. Always check the condition of your batteries after extended use, as drawing very close to empty can damage its ability to hold a charge.
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References
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- Photo Credit battery image by Hao Wang from Fotolia.com
