Glossary

Car battery glossary

38 terms you will hear from a battery technician, each explained in a sentence or two.

12V system: The low-voltage electrical circuit that nearly every car uses for starting, lights, locks and control units. It is fed by a 12-volt battery and recharged by the alternator, or by a DC-DC converter in hybrid and electric cars.
AGM battery: Absorbent Glass Mat battery. A sealed lead-acid battery whose acid is held in glass-fibre mats instead of moving freely. It accepts charge quickly and tolerates repeated deep cycling, which is why many start-stop and high-specification cars use it.Read more
Alternator: The engine-driven generator that powers the electrical system while the engine runs and recharges the battery. If it fails, the car runs off the battery alone until it goes flat, usually with a battery warning light on the dashboard.
Ampere-hour (Ah): A measure of battery capacity: how much current a battery can supply over time. A 70 Ah battery can in theory give 3.5 amps for 20 hours. The right figure is the one specified for the car.
Auxiliary battery: A second, smaller 12V battery fitted to some cars, common on Mercedes-Benz models and hybrids. It supports systems such as start-stop, the gear selector or electronics while the main battery is busy. It ages and needs replacing separately.
Battery management system (BMS): The electronics that monitor battery voltage, current and temperature and tell the alternator how hard to charge. On many modern cars it must be told when a new battery is fitted so charging matches the new unit.
Battery registration: Telling the car computer through a diagnostic tool that a new battery has been fitted, along with its type and capacity. Many BMW, Audi, Volkswagen and other models need it so the charging strategy resets for a fresh battery.Read more
BCI group size: A North American standard from Battery Council International that codes the length, width, height and terminal layout of a battery, for example Group 35 or Group 65. It is the usual reference for American-built cars.
Booster pack: A portable battery unit with clamps used to jump-start a car without a second vehicle. Technicians use professional packs with surge and reverse-polarity protection, which are safer for modern car electronics than improvised cable connections.Read more
Calcium battery: A lead-acid battery whose plates are alloyed with calcium instead of antimony. It loses less water and self-discharges more slowly, so most maintenance-free batteries are calcium types. It can need a slightly higher charging voltage to recharge fully.
Charging system: The alternator, voltage regulator, battery and the cables linking them. Together they keep the battery charged and supply the car while driving. A healthy system typically shows about 13.8 to 14.7 volts at the battery with the engine running.Read more
Cold cranking amps (CCA): A rating of starting power: the current a battery can deliver for 30 seconds at minus 18°C while staying above 7.2 volts. Higher CCA means stronger cranking. Match or slightly exceed the figure on the original battery.
Deep discharge: Draining a battery far below its normal working level, for example by leaving lights on overnight. Starter batteries are not built for it. Each deep discharge causes lasting plate damage, and a battery left flat for days may not recover.
DIN size: A German and European standard for battery case dimensions and ratings, often written in the Gulf market as codes such as DIN 55 or DIN 75. DIN batteries have recessed terminals and a flush top, and fit most European cars.
EFB battery: Enhanced Flooded Battery. A strengthened version of the conventional wet battery with tougher plates and a polyester scrim that holds the active material in place. It handles more engine starts than a standard battery and is fitted to entry-level start-stop cars.Read more
Electrolyte: The mixture of sulphuric acid and water inside a lead-acid battery that reacts with the plates to store and release energy. In hot climates the water part evaporates faster, which exposes the plates and shortens battery life.
Flooded battery: The conventional wet-cell lead-acid battery, with plates sitting in liquid electrolyte. It is the most widely fitted type and suits cars without start-stop. It is more sensitive to heat, vibration and deep discharge than AGM or EFB.
Grid corrosion: Gradual breakdown of the lead grids that hold the active material inside the positive plates. Heat speeds it up, which makes it a leading cause of battery failure in hot countries. It cannot be reversed, only slowed.
Intelligent battery sensor (IBS): A small sensor clamped to the negative battery terminal that measures current, voltage and temperature and reports them to the car. It lets the car estimate battery condition and manage charging. A faulty one can trigger battery warnings.
JIS size: The Japanese Industrial Standard for battery sizes, written as codes such as 55D23L or NS70. The code gives performance rank, case size and terminal side. Most Japanese and Korean cars in the UAE take JIS batteries.
Jump start: Starting a car with a flat battery by lending it power from a booster pack or another vehicle. It gets the engine running but does not repair a worn battery, so a test afterwards shows whether replacement is needed.Read more
Load test: A test that puts a battery under a controlled electrical demand and watches how its voltage holds up. It shows whether a battery can still start the engine, which a simple voltage reading cannot. Many modern testers measure conductance instead.Read more
Maintenance-free battery: A sealed battery that never needs topping up with distilled water during its service life. Nearly all car batteries sold today are this type. Sealed does not mean everlasting: it still wears out and still needs periodic testing.
Memory saver: A small device that keeps the car supplied with 12V power while the battery is disconnected. It preserves radio presets, clock, window and seat settings and stops some control units from needing to relearn after a battery change.Read more
Open-circuit voltage: The voltage of a battery measured at rest, with nothing drawing from it or charging it. A healthy, fully charged 12V battery reads about 12.6 volts or slightly higher. Around 12.0 volts means it is heavily discharged.Read more
Parasitic drain: Current that the car keeps drawing after it is switched off and locked. A small draw for alarms and memory is normal. A faulty module, light or aftermarket accessory can raise it enough to flatten a battery overnight.
Polarity: The position of the positive and negative terminals on a battery. A replacement must have them on the same sides as the original or the cables will not reach. Connecting a battery the wrong way round can damage electronics.
Reserve capacity (RC): The number of minutes a fully charged battery can supply 25 amps at 27°C before its voltage falls to 10.5 volts. It indicates how long the car could keep running on the battery alone if the alternator stopped charging.
Self-discharge: The slow loss of charge that happens inside any battery even when it is disconnected. Heat speeds it up considerably, so a battery in storage or in a parked car loses charge faster in a UAE summer.
Smart alternator: An alternator whose output is controlled by the engine computer instead of a fixed regulator. It lowers charging while accelerating and raises it while braking to save fuel, so the battery is kept partly charged and works harder.
Start-stop system: A fuel-saving feature that switches the engine off when the car stops and restarts it when the driver releases the brake. It multiplies the number of engine starts, so these cars need an AGM or EFB battery.Read more
Starter motor: The electric motor that turns the engine over until it fires. It draws more current than anything else on the car, often several hundred amps for a second or two, which is why a weak battery shows up at starting.
State of charge (SoC): How full a battery is at a given moment, expressed as a percentage of its current capacity. It changes with every drive and every hour parked. A low state of charge can be fixed by recharging, unlike a low state of health.Read more
State of health (SoH): How much of its original performance a battery still has, expressed as a percentage. It falls as the battery ages and never comes back. A battery tester estimates it, and a low reading means replacement is due.Read more
Sulfation (sulphation): A build-up of hard lead sulphate crystals on the battery plates that happens when a battery sits partly or fully discharged. The crystals block the chemical reaction, cutting capacity and starting power. Mild cases can sometimes be reversed by proper charging.
Terminals: The two lead posts or clamps where the car cables connect to the battery, one positive and one negative. Loose or corroded terminals cause poor starting and charging that can look exactly like a failing battery.
Voltage drop: A loss of voltage along a cable or across a connection caused by resistance, usually from corrosion, a loose clamp or a damaged cable. It also describes the dip in battery voltage while cranking, which testers measure.
VRLA battery: Valve Regulated Lead-Acid battery. A sealed lead-acid battery that recombines the gases produced during charging and vents only through a safety valve if pressure rises. AGM and gel batteries are both VRLA types.

Battery guides

Straight answers on car batteries in the UAE

Written by the people who test and fit batteries every day, with sources where the numbers come from somewhere else.

6 min readHow long do car batteries last in the UAE?UAE workshops commonly quote two to three years for a car battery, which is trade experience and not a formal study. Heat is the main reason: it speeds up grid corrosion, water loss and self-discharge. Short trips, heavy air conditioning load and long periods parked shorten life further. A battery test shows the real condition better than age alone.

All battery guides

Arrange roadside battery assistance

Send your location pin, your car details and a short description of the problem. We confirm whether we can reach you and what the car needs.

Location pin and road
Make, model and year
What the car is doing

Send your location Call 800 692288Open 24/7 · Up to 24 months warranty