4.913,260 reviews on GoogleCar battery glossary
The words on your battery label, your quote and your dashboard, in plain language.
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CardCashThe short answer
A car battery label lists its capacity in amp-hours (Ah), its starting power in cold-cranking amps (CCA), its size standard (JIS, DIN or BCI) and its technology (flooded, EFB or AGM). This glossary explains each of those terms and the others a technician is likely to use.
- AGM battery
- Absorbent glass mat. A sealed lead-acid battery with its acid held in glass fibre mats between the plates, built for start-stop cars with brake energy recovery and for heavy electrical loads.Read more
- Alternator
- The belt-driven generator that powers the car's electrics and recharges the battery while the engine runs. A working one charges at roughly 13.8 to 14.7V.Read more
- Amp-hour (Ah)
- The battery's capacity: how much current it can supply over time. A 70Ah battery can in theory deliver 3.5 amps for 20 hours before it is flat.
- Auxiliary battery
- A second, smaller battery fitted to some cars, including many Mercedes-Benz, Volvo and Jeep models, that supports start-stop or backup functions. It fails separately and shows its own warning message.Read more
- Battery coding
- Changing the battery capacity or type stored in the car when the new battery differs from the old one, for example from flooded to AGM.Read more
- Battery registration
- Telling the car with a scan tool that a new battery has been fitted, so the battery monitoring system resets its ageing data and charges correctly.Read more
- Battery sensor (IBS) and BMS
- The intelligent battery sensor is a small module on the negative terminal that measures current, voltage and temperature. The battery monitoring system uses those readings to manage charging and start-stop.Read more
- BCI
- Battery Council International. The North American size system used by American cars, with group numbers such as 65, 78, 48 (H6), 94R (H7) and 49 (H8).
- Booster pack
- A portable battery with clamps, used to jump start a car without a second vehicle.Read more
- Calcium battery
- A battery whose plate grids are alloyed with calcium in place of antimony. It loses less water and self-discharges more slowly, which is what makes sealed maintenance-free batteries possible.
- Cold-cranking amps (CCA)
- The current a battery can deliver for 30 seconds at -18°C while staying above 7.2V. It is the standard measure of starting power, and a tester compares the measured figure with the one on the label.Read more
- Conductance test
- A quick electronic test that passes a small signal through the battery to estimate its cranking amps and state of health without discharging it.Read more
- Cranking voltage
- The battery voltage measured while the starter is turning the engine. On a healthy battery it usually stays above about 9.6V.
- Date code
- The stamp or sticker showing when a battery was made or shipped. It tells you the age of the battery in a used car and how long a new one has stood in stock.
- DC-DC converter
- The unit in a hybrid or electric car that steps the high-voltage pack down to charge the low-voltage battery. It does the job an alternator does in a petrol car.
- Deep discharge
- Running a battery down far below its normal working range, for example by leaving the lights on overnight. Each deep discharge costs a starter battery some of its capacity for good.
- DIN
- The German and European size standard, with sizes such as DIN55, DIN66, DIN75, DIN88 (H7) and DIN100 (H8). These batteries have a flat top with the terminals set below its surface.
- EFB battery
- Enhanced flooded battery. A flooded battery with reinforced plates that withstands many more engine starts, used in entry-level start-stop cars.Read more
- Electrolyte
- The mix of sulphuric acid and water inside a lead-acid battery that carries current between the plates. UAE heat evaporates the water in it.
- Flooded battery
- The conventional lead-acid design, with plates standing in liquid acid. It suits cars without start-stop.Read more
- Group size
- A code that fixes a battery's length, width, height and terminal position, so that it fits the tray and the cables reach. JIS, DIN and BCI each have their own codes.Read more
- Hold-down clamp
- The bracket that fixes the battery to its tray. A loose one lets the battery vibrate, which damages the plates.
- JIS
- Japanese Industrial Standard. The battery size system used by most Japanese and Korean cars, with codes such as NS40, NS60, 55D23L and 80D26L.
- Jump start
- Starting a car that has a flat battery by borrowing current from another car's battery or a booster pack through jump leads.Read more
- Load test
- A test that draws a heavy current from the battery for a few seconds and watches how far the voltage drops. It shows whether the battery can still crank an engine.Read more
- Low-voltage battery (EVs and hybrids)
- The 12V battery in a hybrid or electric car, or the 16V lithium pack in newer Teslas. It powers the locks, screens and the contactors that connect the main drive battery.Read more
- Memory saver
- A small power supply connected while the battery is out, so the radio, clock and window settings are kept where the car allows it.Read more
- Parasitic drain
- Current drawn from the battery while the car is switched off, by alarms, trackers, control units or a faulty component. A small drain is normal, while an excessive one flattens a healthy battery in days.
- Regenerative braking
- Also called brake energy recovery. The alternator or electric motor charges the battery hardest while the car slows down, storing energy that would otherwise be lost as heat.
- Reserve capacity (RC)
- The number of minutes a fully charged battery can supply 25 amps before its voltage falls to 10.5V. It shows how long the car's electrics could run if the alternator stopped charging.
- Resting voltage
- The battery voltage with the engine off after the car has stood for a few hours. About 12.6V indicates a healthy, fully charged battery.
- Smart alternator
- An alternator whose output is controlled by the engine computer. It charges harder when you lift off or brake and eases off under acceleration to save fuel, so its voltage varies by design.
- SMF battery
- Sealed maintenance-free. A flooded battery with a sealed lid that never needs topping up with water, and the common type for ordinary cars in the UAE.
- Specific gravity
- The density of the electrolyte compared with water, measured with a hydrometer on batteries that have removable caps. About 1.26 to 1.28 indicates a full charge.
- Start-stop
- A system that switches the engine off when the car stops in traffic and restarts it as you release the brake. It needs an EFB or AGM start-stop battery.Read more
- Starter motor
- The electric motor that turns the engine to start it, and the heaviest single load on the battery. One click with bright lights usually points to the starter and not the battery.Read more
- State of charge (SoC)
- How full the battery is at this moment, as a percentage. About 12.6V at rest is fully charged, about 12.2V is half and under 12.0V is discharged.
- State of health (SoH)
- How much of its original capacity and cranking power a battery still has, whatever its charge level. A battery can be fully charged and still have a poor state of health.Read more
- Sulphation
- Hard lead sulphate crystals that build up on the plates when a battery is left partly charged. They cut capacity and cranking power and are the usual end of batteries used for short trips.Read more
- Terminal layout (L/R)
- Which side the positive terminal sits on. In JIS codes the final L or R marks it, as in 55D23L, and a battery with the wrong layout may leave the cables too short to connect.
- Trickle charger
- A low-current charger that keeps the battery of a parked car topped up. A smart maintenance type stops charging once the battery is full.
- Vent tube
- A small hose that carries charging gases from the battery to the outside of the car. It must be reconnected on batteries fitted in the boot or under a seat.
Which battery type does your car need
The label on your current battery tells us. These are the four you will meet in Dubai.
Flooded and maintenance-free
SMF- Fits
- Most petrol cars without start-stop: Corolla, Sunny, Accent, Pajero, older Land Cruiser.
- In UAE heat
- The most affected by heat. Expect about two to three summers.
- How to spot it
- Flat top, sometimes a green indicator eye. Labels such as NS60, 55D23L or DIN66.
Enhanced flooded
EFB- Fits
- Entry start-stop cars and many newer Japanese and Korean models.
- In UAE heat
- Handles frequent restarts and partial charge better than a standard battery.
- How to spot it
- "EFB" or "Start-Stop" printed on the label.
Absorbent glass mat
AGM- Fits
- BMW, Mercedes, Audi, Range Rover, Porsche and any car with start-stop and brake energy recovery.
- In UAE heat
- Sealed and vibration-proof. Often in the boot, away from engine heat.
- How to spot it
- "AGM" or "VRLA" on the label. An AGM car must get AGM again.
Lithium low-voltage
Li- Fits
- Newer Tesla models and a growing number of EVs and plug-in hybrids.
- In UAE heat
- Managed by the car. Replaced like for like, never with lead-acid.
- How to spot it
- Small, light, with a data connector as well as power terminals.
More than batteries
While we are at your car, or any other day, the same number books these.
- 24/7 car roadside assistanceBattery, tyre, fuel or a flatbed, from one WhatsApp message at any hour
- Car recoveryFlatbed for breakdowns, accident damage and cars too low to tow
- Flat tyre fixSpare fitted, tyre inflated or a nail hole plugged where you are stuck
- Car AC repairThe fault found with gauges before any part or gas is sold
- Oil changeThe right grade and a new filter, on the schedule UAE heat calls for
- Brake pad replacementNew brake pads fitted, discs measured, sensors and slides sorted.
Battery trouble right now?
Message your location. You will have a price and an arrival time within minutes, and a technician on the way from Arjan.
Open 24 hours. Free delivery and fitting. Up to 24 months warranty.