Hybrid car batteries are half of the equation that makes a hybrid car more fuel efficient than a conventional automobile. While normal gas-powered cars also use batteries, there is a difference in how they are constructed and how much energy they store. Both types of batteries can be recharged, but that’s where the similarities end.
The battery in a regular car is called a lead acid battery. It stores just enough energy to drive a small motor. The battery generates enough torque to start a car, turning the engine over at 300 RPMs. When the weather is cold, the engine is tight and the oil is thick. The battery needs to output more energy to get the engine turned over. This is the “cold-cranking amps” that you hear about in advertisements. The engine only needs a short burst of current to start a car. Other accessories such as lights, wipers, radio, lights, and other electrically-powered gadgetry also draw their power from the battery. Once the car is started, the electrical power responsibilities are handed off to the alternator. The alternator also recharges the battery while it is running.
The hybrid car actually uses the same exact lead acid battery for the same purposes that a gas-powered car uses one. Additionally, they are equipped with hybrid car batteries which are different from the lead acid variety. Hybrid car batteries are also known as a deep cycle battery. Unlike the lead acid battery which loses its usefulness when fully discharged, hybrid car batteries are designed to be fully discharged and recharged, much like a cellular phone or camcorder battery. Hybrid car batteries must hold a lot of stored energy to power a car while on the road, unlike the short electrical burst nature of the lead acid battery.
Hybrid car batteries are bulky and heavy. In the late 1990s, an Electric Ranger battery by Ford weighed 1600 pounds. These usually consisted of an array of smaller batteries interconnected to create one high-voltage battery.
A hybrid car, by definition, combines two energy sources into one – in this case, a gas engine and an electric vehicle battery. Instead of lead acid, Nickel Metal Hydride (NiMH) is used in order to reduce weight and offer more energy from a compact package. The gas engine still takes up the majority of the room under the hood, so the battery isn’t as large as the old Electric Vehicle batteries that never caught on. In the Toyota Prius and Honda Civic, the battery voltage is 300 volts and up. While lead acid car batteries measure energy in cranking amps, hybrid batteries use kilowatt amp-hours.
* Prius and the Honda Insight, when they were first in production, used stick-arranged NiMH D cells. The newer Prius and Civics use a battery pack that houses cells that are connected in arrays.