How Batteries Work

Battery arrangement determines voltage and current. Check out serial battery arrangements, parallel arrangements and what maximum current is about.

Battery Arrangement and Power

In many devices that use batteries -- such as portable radios and flashlights -- you don't use just one cell at a time. You normally group them together in a serial arrangement to increase the voltage or in a parallel arrangement to increase current. The diagram shows these two arrangements.

The upper diagram shows a parallel arrangement. The four batteries in parallel will together produce the voltage of one cell, but the current they supply will be four times that of a single cell. Current is the rate at which electric charge passes through a circuit, and is measured in amperes. Batteries are rated in amp-hours, or, in the case of smaller household batteries, milliamp-hours (mAH). A typical household cell rated at 500 milliamp-hours should be able to supply 500 milliamps of current to the load for one hour. You can slice and dice the milliamp-hour rating in lots of different ways. A 500 milliamp-hour battery could also produce 5 milliamps for 100 hours, 10 milliamps for 50 hours, or, theoretically, 1,000 milliamps for 30 minutes. Generally speaking, batteries with higher amp-hour ratings have greater capacities.

The lower diagram depicts a serial arrangement. The four batteries in series will together produce the current of one cell, but the voltage they supply will be four times that of a single cell. Voltage is a measure of energy per unit charge and is measured in volts. In a battery, voltage determines how strongly electrons are pushed through a circuit, much like pressure determines how strongly water is pushed through a hose. Most AAA, AA, C and D batteries are around 1.5 volts.

Imagine the batteries shown in the diagram are rated at 1.5 volts and 500 milliamp-hours. The four batteries in parallel arrangement will produce 1.5 volts at 2,000 milliamp-hours. The four batteries arranged in a series will produce 6 volts at 500 milliamp-hours.

Battery technology has advanced dramatically since the days of the Voltaic pile. These developments are clearly reflected in our fast-paced, portable world, which is more dependent than ever on the portable power source that batteries provide. One can only imagine what the next generation of smaller, more powerful and longer-lasting batteries will bring.

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