Automotive battery
For this reason, automotive batteries are designed to deliver maximum current for a short period of time.
[3] While the engine is running most of the power is provided by the alternator, which includes a voltage regulator to keep the output between 13.5 and 14.5 V. Modern SLI batteries are lead-acid type, using six series-connected cells to provide a nominal 12-volt system (in most passenger vehicles and light trucks), or twelve cells for a 24-volt system in heavy trucks or earth-moving equipment, for example.
[7] Further, an electric vehicle does not have a starter motor, thus needs only a limited amount of power and energy from its auxiliary battery.
The changeover from 6 to 12 V happened when bigger engines with higher compression ratios required more electrical power to start.
[13] Smaller cars, which required less power to start stayed with 6 V longer, for example the Volkswagen Beetle in the mid-1960s and the Citroën 2CV in 1970.
However, the availability of higher-efficiency motors, new wiring techniques, and digital controls, and a focus on hybrid vehicle systems that use high-voltage starter/generators have largely eliminated the push for switching the main automotive voltages.
The filler cap had a small vent hole which allowed hydrogen gas generated during charging to escape from the cell.
A pair of heavy terminals, plated with lead to resist corrosion, are mounted at the top, sometimes the side, of the battery.
Modern units use plastic cases and woven sheets to prevent the plates of a cell from touching and short-circuiting.
"Low-maintenance" (sometimes called "zero-maintenance") batteries use a different alloy for the plate elements, reducing the amount of water decomposed on charging.
A modern battery may not require additional water over its useful life; some types eliminate the individual filler caps for each cell.
The cells each have an automatic pressure release valve, to protect the case from rupture on severe overcharge or internal failure.
As the battery discharges, the acid of the electrolyte reacts with the materials of the plates, changing their surface to lead sulfate.
For weight savings, the 2010 Porsche 911 GT3 RS has a lithium-ion battery as an option;[19] from 2018 onward, all Kia Niro conventional hybrids feature one as well.
In theory, at 80 degrees F, a 100 Ah battery should be able to continuously provide 5 amps for 20 hours while maintaining a voltage of at least 10.5 volts.
[34] SLI batteries (starting, lighting, and ignition) are not designed for deep discharge, and their life is reduced when subjected to this.
Modern car batteries have reduced maintenance requirements, and may not provide caps for addition of water to the cells.
This can be substantially reduced by enclosing one set of plates in plastic separator bags, made from a permeable material.
The 12-volt car battery is the most recycled product in the world, according to the United States Environmental Protection Agency.
Pure Earth estimates that over 12 million people in developing countries are affected by lead contamination from ULAB processing.
