What Is A Car 12v Battery?
Almost all car batteries are 12-volt, lead-acid batteries. The ability of a 12v battery to supply high surge currents means that cells have a relatively large power-to-weight ratio, making them a great fit for the automotive industry.
Cars have more technology installed that requiring electrical power to operate than ever before. Some of these electrical devices include the ignition system, starter motor, engine controls and most recently, car infotainment systems. A 12v battery is required to enable these electrical systems to store energy to use them when the engine isn’t running, and the alternator isn’t the source of electrical energy.
12v Car Battery Voltage
Modern cars operate using a 12-volt, direct-current electrical system. A 12v car battery has a nominal voltage closer to 12.6-volts, as opposed to the 12v you typically see on battery packaging. A 12v car battery consist of six electrical cells containing lead plates with oxide coatings, separated by a fixed distance. The electrochemical reaction between the plates being dropped in the battery electrolyte causes the voltage difference between the negative and positive battery terminals.
Cranking Amps and Cold Cranking Amps
These two metrics are used for rating the electrical current capacity of a 12v battery. Cranking amps (CA) refers to how many amps a battery can provide for 30 seconds, whilst maintaining voltage of at least 7.2-volts, at a temperature of 0°C. Cold cranking amps (CCA) refers to the same as the above but at a temperature of -17°C. Cold cranking amps are a good indication of a battery’s ability to start a car engine in cold temperatures. The electrochemical process that produces battery energy is limited in cold temperatures, which means a car battery will always produce more cranking amps than cold cranking amps.
Battery Reserve Capacity, Amp Hour and C20
Reserve Capacity (RC) is a useful indicator of a fully charged battery’s ability to perform (operating electrical systems) when the alternator fails.
Amp hour and C20 metrics are used to indicate how much energy is stored within a 12v battery.
12v Car Battery Replacement
We hope that you are now clued up on 12v car batteries and hope that you found this guide useful. We are one of the UK’s largest sellers of high-quality, cheap used 12v car batteries. Shop online or visit our Poole site and find the car battery replacement you need for less. We offer FREE fitting and expert disposal of your old battery on site and every 12v battery sold (online or on site) comes with a FREE 12 month peace of mind warranty.