A car's starting battery (SLI) is designed to deliver quick bursts of energy required in starting engines.
Other functions
Supply additional power necessary when the vehicle's electrical load exceeds the supply from the charging system (alternator)
Voltage stabilization of the electrical system. The battery evens out voltage spikes and prevents them from damaging other components in the electrical system.
Features of a good car battery
Rechargeable
Deliver a short burst of high current/power to start the engine
Stabilize the automobile's electrical system
Sometimes referred to as "SLI batteries", (Starting, Lighting, and Ignition), automotive batteries are not designed for deep discharging, and a full discharge can reduce the battery's lifespan.
Early cars did not have batteries as their electrical systems were limited: -
A bell was used instead of an electric horn,
Headlights were gas-powered,
Engine was started with a crank.
Car batteries became widely used around 1920 as cars became equipped with electric starters. The sealed battery (maintenance free), which did not require refilling, was invented in 1971.
Some vehicles use special starter batteries. The 2010 Porsche 911 GT3 RS has a lithium-ion battery as an option to save weight.Heavy vehicles may have two batteries in series for a 24V 70Ah system or may have parallel groups of batteries supplying 12V and 140Ah.
The physical size and performance parameters of a battery is dictated by their size name.
