Battery buying help
Car Battery Glossary
A car battery label and a replacement quote use the same handful of terms: capacity in Ah, starting current in CCA, a DIN or JIS size, and a technology such as AGM or EFB. This glossary explains each one in plain English so you can check that a quoted battery matches your car before you approve it.
Ah, CCA and reserve capacity compared
| Rating | What it measures | How to use it |
|---|---|---|
| Ah (ampere-hours) | Capacity: how much charge the battery stores | Match the capacity the vehicle specifies |
| CCA (cold cranking amps) | Starting current in a standard cold test | Meet or exceed the specified figure, using the same test standard |
| RC (reserve capacity) | Minutes the battery can supply 25 A | Compare how long electrical loads are supported without charging |
DIN, JIS and BCI battery sizes compared
| System | Usually found on | How it is labelled | Typical features |
|---|---|---|---|
| DIN | European cars and many newer models | Capacity class, for example DIN 70 Ah | Recessed terminals, hold-down lip on the base |
| JIS | Japanese and Korean cars | Code such as 55B24L or 80D26L | Raised terminals, thick or thin posts |
| BCI | American-market vehicles | Group number such as 24, 35 or 65 | Group number fixes case size and terminal layout |
The region a car was built for matters more than its badge. An imported American-specification model can use a different battery from the GCC-specification version of the same car, so check the existing label or send us the vehicle details.
Battery ratings and label terms
These figures are printed on the battery label. Match them to the vehicle specification rather than choosing the largest number.
- Ampere-hour (Ah)
- Ampere-hours describe battery capacity: how much charge the battery can deliver under a standard test, normally over 20 hours for a car starter battery. A 70 Ah battery stores more energy than a 45 Ah battery, but the correct figure is the one specified for your vehicle and its tray size.
- Cold cranking amps (CCA)
- CCA is the starting current a battery can deliver in a standard cold test at -18 °C. It indicates starting power, not capacity. EN, SAE, DIN and JIS test methods produce different numbers for the same battery, so compare two batteries using the same standard.
- EN rating
- The European Norm starting-current figure, shown in amps with “EN” beside it. It is one of several cold-cranking test standards and is the figure most European-pattern battery labels quote.
- Reserve capacity (RC)
- Reserve capacity is the number of minutes a fully charged battery can supply 25 amps before its voltage falls to 10.5 V. It indicates how long the battery could support essential electrical loads without charging.
- 12-volt nominal voltage
- A car battery has six cells of roughly 2.1 V each, giving a nominal 12 V. A rested, fully charged lead-acid battery reads around 12.6 V or slightly higher. Voltage helps assess charge, but it cannot prove on its own that a battery can still start the engine reliably. Mobile car battery testing in Dubai
- State of charge (SoC)
- How full the battery is at the moment of measurement, as a percentage. A healthy battery can have a low state of charge after lights were left on or after weeks of parking.
- State of health (SoH)
- How much of its original performance a battery can still deliver. A battery can be fully charged and still have poor health. A suitable tester estimates health from the battery technology and its rated values. Mobile car battery testing in Dubai
- Date code
- A stamped or printed code showing when the battery was manufactured. Formats differ by brand. Ask the seller to confirm the production date and note it on the invoice with the warranty start date.
Battery sizes and fitment
A battery must fit the tray, reach the cables and clamp securely. These terms describe the physical format.
- DIN battery
- A battery built to the European case pattern, with recessed terminals and a hold-down lip along the base. DIN batteries are common in European cars and many newer models from other regions. Catalogues list them by capacity, for example “DIN 45 Ah” or “DIN 70 Ah”. Buy a car battery online in Dubai
- JIS battery
- A battery built to the Japanese Industrial Standard pattern, common in Japanese and Korean cars. The code describes the battery: in 55B24L, 55 is the performance rank, B is the width and height class, 24 is the approximate length in centimetres and L or R shows the terminal arrangement. An added S, as in 55B24LS, indicates standard thick terminal posts instead of thin ones. Buy a car battery online in Dubai
- BCI group size
- The North American case-size system from Battery Council International, written as a group number such as 24, 35 or 65. It appears on many American-market vehicles.
- Terminal layout (polarity)
- Which side the positive and negative posts sit on. Two batteries of the same size can have opposite layouts. If the layout is wrong, the cables may not reach or may be strained, so it is checked alongside the case size.
- Thick and thin terminal posts
- JIS batteries are made with either standard thick posts or thinner “pencil” posts. The cable clamps on the car fit only one of them properly.
- Hold-down
- The clamp or bracket that secures the battery in its tray, either across the top or on a lip at the base. A battery that is not held firmly suffers vibration damage and can move against other components.
Battery technologies
The technology your vehicle was built for decides which replacement is suitable. Hot weather alone does not.
- Flooded lead-acid battery
- The conventional starter battery, with lead plates in liquid electrolyte. Also called an SLI battery, for starting, lighting and ignition. It suits vehicles designed for it, usually without automatic start-stop. AGM, EFB and standard battery types
- Maintenance-free (MF) battery
- A sealed flooded battery that does not need topping up with water in normal use. Most car batteries sold today are maintenance-free.
- EFB (enhanced flooded battery)
- A strengthened flooded battery that tolerates more charge and discharge cycles than a conventional one. It is fitted to many cars with basic start-stop systems. AGM and EFB start-stop battery replacement
- AGM (absorbent glass mat)
- A sealed lead-acid battery in which the electrolyte is held in glass-fibre mats instead of flowing freely. AGM handles frequent cycling and high electrical demand, and is specified for more advanced start-stop systems and cars with energy recovery. An AGM battery is replaced with another AGM battery. AGM and EFB start-stop battery replacement
- Calcium and silver-calcium battery
- A lead-acid battery whose plate grids use a calcium alloy, sometimes with silver, to reduce water loss and self-discharge. It describes the grid material and can apply to flooded, EFB or AGM batteries.
- Gel battery
- A sealed lead-acid battery with the electrolyte set into a gel. Gel batteries suit slow, deep discharge in applications such as mobility equipment and are rarely specified as car starter batteries.
- Deep-cycle battery
- A battery designed to be discharged deeply and recharged repeatedly, for example in boats or caravans. It is not a substitute for a starter battery unless the vehicle manufacturer specifies one.
- 12 V lithium battery
- A lithium-ion low-voltage battery used by some electric and performance vehicles in place of a lead-acid battery. It needs matching charging control, so it is only fitted where the vehicle was designed for it.
- Auxiliary battery
- A second, smaller battery that supports electronics or the start-stop system in some cars. In hybrids and electric vehicles, the term also refers to the 12 V battery that powers the car’s computers, locks and lights separately from the high-voltage traction battery.
Vehicle charging and battery-management terms
A battery is one part of a system. These terms come up when a new battery keeps going flat or a car needs more than a straight swap.
- Start-stop system
- A fuel-saving function that switches the engine off when the car is stationary and restarts it automatically. It relies on an EFB or AGM battery and a battery sensor. The car suspends it deliberately when cabin cooling demand is high or the battery charge is low. AGM and EFB start-stop battery replacement
- Battery-management system (BMS)
- The vehicle electronics that monitor battery current, voltage and temperature, usually through an intelligent battery sensor on the negative terminal, and adjust charging to suit the battery’s age and condition.
- Battery registration (coding)
- Telling the battery-management system that a new battery has been fitted, using a diagnostic tool. Some vehicles require it after replacement; others relearn automatically. Where it is required and skipped, start-stop and comfort functions can be restricted. AGM and EFB start-stop battery replacement
- Alternator
- The engine-driven generator that powers the car’s electrical system and recharges the battery while the engine runs. A battery warning light that stays on while driving points to the charging system and needs checking, not only the battery. Car electrical diagnostics
- Smart charging
- A charging strategy in which the car varies alternator output to save fuel, charging harder when slowing down and less when accelerating. Charging voltage on these cars moves over a wider range than on older vehicles.
- Parasitic drain
- The small current a parked car draws for its alarm, computers and memory. Added accessories such as dashcams and trackers increase it. Excessive drain flattens a healthy battery and is found by electrical diagnosis, not by fitting another battery. Car electrical diagnostics
Battery faults and service terms
Words you may hear from a technician during a call-out. Leave handling of a damaged battery to a professional.
- Jump start
- Supplying temporary power from another battery or a booster pack so a car with a discharged battery can start. It does not recharge or repair the battery. Connection points differ by vehicle, and a swollen, leaking or damaged battery must not be jump-started. Car jump start service in Dubai
- Battery test (conductance and load testing)
- An electronic conductance tester estimates battery health from the battery’s rating and technology; a load test measures how voltage holds while current is drawn. The usual results are good, charge and retest, or replace. Mobile car battery testing in Dubai
- Self-discharge
- The gradual loss of charge in a battery that is not being used. It speeds up as temperature rises, which is why a car parked through a UAE summer can struggle to start. Car battery care in UAE heat
- Deep discharge
- Draining a battery far below its normal operating range, for example by leaving lights on overnight. A starter battery can be permanently weakened by it, and damage from deep discharge is commonly excluded from battery warranties.
- Sulphation
- The build-up of hardened lead sulphate on the plates when a battery stays partly or fully discharged. It reduces capacity and starting power and is a common result of long parking and repeated short trips.
- Terminal corrosion
- White, green or blue deposits on the battery posts and clamps. Corrosion adds electrical resistance and can cause slow starting even when the battery itself is sound.
- Swollen battery
- A battery case that has bulged, usually from overheating or overcharging. Do not jump-start, charge or continue using it. Keep clear and arrange professional replacement. 24/7 emergency battery service
- Used lead-acid battery (scrap battery)
- The old battery removed at replacement. It contains lead and acid, is classed as hazardous waste and is recyclable. It should be handed to the installer or an approved recycler, never placed in general waste. Battery delivery, warranty and payment FAQ
Not sure what your battery label means?
Send a photo of the label if the battery is safely accessible, or your vehicle make, model and year. We will confirm the compatible battery, the fitted price in AED and the arrival estimate for your location in Dubai, Abu Dhabi or Sharjah.