24/7 · Glossary
Car Battery & Roadside Glossary
The words on a battery label, a repair quote or a roadside call, explained in plain English.
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Battery Basics
The numbers and labels printed on a car battery, and what they tell you.
- 12-volt battery
- The standard battery in petrol and diesel cars, also used as the auxiliary battery in many hybrids and electric cars. It starts the engine and powers the electrics while the engine is off.
- Learn more: Car battery replacement
- Amp-hour (Ah)
- The capacity figure on the label, measured over a 20-hour discharge. Your replacement should match the Ah your car's maker specifies.
- Cold cranking amps (CCA)
- The current a battery can deliver for 30 seconds at minus 18°C while keeping a usable voltage. Dubai never gets that cold, but CCA is still the standard way to compare starting strength between batteries.
- Reserve capacity (RC)
- The number of minutes a fully charged battery can run the car's essentials if the alternator stops charging. A higher figure gives you more time to reach help.
- Resting voltage
- The battery's voltage after the car has been off for a few hours with nothing drawing power. It is the most reliable quick reading of charge, because a running engine or a recent drive pushes the figure up.
- State of charge
- How full the battery is, shown as a percentage. A battery left at a low state of charge for a long time loses capacity for good.
- Battery group size (DIN and JIS)
- The standard that fixes a battery's dimensions, terminal type and layout. European cars mostly use DIN sizes and Japanese and Korean cars use JIS sizes, so the code on your old battery is the quickest way to find a match.
- Terminal layout
- Which side the positive and negative posts sit on. Two batteries of the same size can have mirrored layouts, and the wrong one may leave the cables too short to reach.
Battery Types
The main kinds of battery fitted to cars in Dubai, and the cars each one suits.
- Flooded lead-acid battery
- The traditional battery, with lead plates sitting in liquid electrolyte. It suits cars without start-stop and is usually the most affordable option.
- Sealed maintenance-free (SMF) battery
- A flooded battery built with calcium alloy plates and a sealed lid with no filler caps. The calcium reduces gassing, which is what keeps the electrolyte level steady.
- Enhanced flooded battery (EFB)
- A stronger flooded battery made for entry-level start-stop systems. It copes with frequent restarts far better than a standard flooded battery.
- Absorbent glass mat (AGM) battery
- A sealed battery whose electrolyte is held in glass fibre mats instead of free liquid. It handles the deep, frequent cycling of advanced start-stop systems and heavy electrical loads, and is usually coded to the car when fitted.
- Auxiliary battery
- A small secondary battery that some cars, many German models among them, use to support start-stop and the electronics. When it fails it often triggers a warning message even though the main battery is fine.
- Learn more: Auxiliary batteries
- 12V lithium battery
- A lighter starter battery built on lithium chemistry, found in some sports and performance cars. It needs a charging system designed for it, so it should only replace another lithium battery.
- Heat-resistant battery
- A battery built with extra electrolyte or tougher plates to cope with high temperatures. In Dubai, heat wears batteries out faster than cold weather does in cooler countries.
Charging & Starting
The parts that start the engine and keep the battery charged while you drive.
- Alternator
- The engine-driven generator that charges the battery and powers the electrics while the engine runs. If it fails, the car runs on the battery alone until the battery goes flat.
- Learn more: Alternator and dynamo repair
- Dynamo
- An older type of generator that produces direct current. Many drivers use the word for any car generator, including the alternator.
- Voltage regulator
- The part that keeps the alternator's output within a safe range. A faulty regulator can overcharge the battery or leave it undercharged.
- Drive belt
- The rubber belt, often called the serpentine or alternator belt, that turns the alternator from the engine. A worn or slipping belt can squeal and stop the battery charging properly.
- Starter motor
- The electric motor that turns the engine over when you start the car. A single click with no cranking can point to the starter rather than the battery.
- Battery terminals and clamps
- The posts on the battery and the clamps that connect the car's cables to them. Loose or dirty connections can stop a good battery from starting the car.
Problems & Symptoms
Common signs that a battery or charging system needs attention.
- Slow crank
- When the engine turns over more slowly than usual before it starts. It is often the first sign of a weak battery, especially after a hot spell.
- Parasitic drain
- Power drawn from the battery while the car is switched off, by alarms, trackers or a fault that keeps a module awake. A small drain is normal, but a large one can flatten a battery overnight.
- Deep discharge
- Running a battery down until it is nearly empty. Repeated deep discharges damage the plates and shorten battery life.
- Sulphation
- A build-up of lead sulphate crystals on the plates when a battery stays undercharged. Over time the crystals harden and the battery can no longer hold a full charge.
- Swollen battery case
- A battery whose sides bulge outwards, usually from heat or overcharging. It should be replaced, and it should not be jump started.
- Terminal corrosion
- The white, green or blue crust that forms on battery terminals. It blocks current and can cause starting problems even when the battery itself is healthy.
- Battery warning light
- The red battery symbol on the dashboard. Despite its name, it usually means the charging system is not working, so the alternator and drive belt should be checked.
Roadside & Service Terms
Words you may hear when you call for help at the roadside.
- Jump start
- Starting a car with a flat battery by connecting it to an outside power source for a few moments. Once the engine runs, the alternator takes over the charging.
- Learn more: Jump start service
- Jump starter pack
- A portable battery with its own clamps, charged in advance. It holds enough power to start an engine several times before it needs recharging.
- Battery load test
- A test that puts a heavy load on the battery and watches how far its voltage drops. It shows whether the battery can still deliver starting power, which a voltage reading alone cannot.
- Battery registration
- Telling the car's computer that a new battery has been fitted, using a diagnostic tool. Many modern cars need it so the charging system treats the new battery correctly.
- Start-stop system
- A feature that switches the engine off when the car stops and restarts it when you move off. It puts extra load on the battery, which is why these cars need an EFB or AGM battery.
- Flatbed towing
- Carrying a car on the flat deck of a recovery truck instead of pulling it on its own wheels. The car is winched up the tilted deck and strapped down for the trip.
- Learn more: Car towing
- Car recovery
- Getting a broken-down or damaged car from where it stopped to a place where it can be repaired. Depending on where the car is, it can mean towing, winching or lifting.
- Learn more: Car recovery
- Puncture repair
- Sealing a hole in the tread so the tyre holds air again. Holes in the sidewall cannot be repaired safely and need a new tyre.
- Learn more: Flat tyre repair
- Space saver spare
- A narrow, lightweight spare wheel meant for short distances at reduced speed. It gets you to a tyre fitter but should not stay on the car.
- Learn more: Flat tyre change
- Run-flat tyre
- A tyre with stiff sidewalls that can carry the car for a limited distance after losing pressure. Cars fitted with them often have no spare wheel.
- Hard shoulder
- The emergency lane at the edge of a highway. It is for breakdowns only, so stay well away from passing traffic while you wait for help.
- Learn more: Roadside assistance
Know the term, but not the fault?
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