AGM (Absorbent Glass Mat)
Battery with electrolyte absorbed in a glass fibre mat. Lifespan roughly double that of a conventional battery. Required for advanced Start-Stop.
Verified customer reviews about baterias.com on Trustpilot.
Battery Glossary
Clear, verifiable definitions of 35 key concepts in automotive batteries: technologies (AGM, EFB, GEL, LFP), specifications (CCA, Ah, RC, voltage), vehicle features (Start-Stop, regenerative braking, MHEV/HEV/PHEV/BEV), physical/installation (polarity, terminals, case L0-L6), maintenance, standards (EN 50342, DIN, JIS, TecDoc) and commercial topics (OEM, equivalents, warranty).
Technologies
EFB (Enhanced Flooded Battery)
A reinforced lead-acid battery designed for basic Start-Stop. About twice the cycle life of an SLI, at a lower price than AGM.
GEL (Gel battery)
Lead-acid with gelled electrolyte. Specialised for deep cycle use: boats, mobility scooters, solar systems, caravans.
SLI (Starting Lighting Ignition)
Conventional starting battery, flooded lead-acid. Not suitable for Start-Stop. Typical service life 3-5 years.
Lead-acid battery
Base technology for automotive batteries: lead plates + sulphuric acid electrolyte. Invented by Planté in 1859.
Deep cycle
Battery designed for repeated deep discharges. Uses: marine, solar, caravans, mobility scooters.
LFP / LiFePO4 (Lithium Iron Phosphate)
Lithium iron phosphate battery: 4-5× longer service life than lead-acid, half the weight, no fire risk.
Technical specifications
CCA (Cold Cranking Amps)
Current the battery can deliver at -18°C for 30 seconds while keeping above a minimum voltage. Determines cold-start capability.
Ah (Amp-hour)
Electrical capacity: 60 Ah delivers 60 A for 1 hour, or 1 A for 60 hours. Indicates how much energy the battery stores.
Voltage (V)
Potential difference between terminals. Automotive standard: 12 V (6 cells × 2.0 V). Trucks: 24 V (12 cells).
RC (Reserve Capacity)
Minutes the battery delivers 25 A while staying above 10.5 V. Measures autonomy with engine off or alternator failed.
C20 / C5 / C100 (discharge rate)
Standard discharge rate: C20 = discharge the battery in 20 h. It is the reference used to publish nominal Ah.
SOC (State of Charge)
Charge state in %. 100% = full battery; 0% = empty. Estimated by reading open-circuit voltage at rest.
DoD (Depth of Discharge)
Depth of discharge: % of capacity consumed. 50% DoD = battery has 50% capacity remaining.
SOH (State of Health)
Battery health: current capacity vs nominal. 100% = new battery; 70-80% = end of practical service life.
Vehicle features
Start-Stop
System that switches off the engine at stops (traffic lights) to save 5-15% fuel. Requires EFB or AGM battery.
Regenerative braking
The alternator recovers energy during braking and uses it to charge the battery. Reduces fuel use and brake-pad wear.
MHEV (Mild Hybrid Electric Vehicle)
Light hybrid system with a secondary 48 V network that assists the engine on acceleration and recovers energy on braking.
HEV (Full Hybrid)
Vehicle with combustion engine + electric motor that can move the car in EV mode for short distances. Does not plug in.
PHEV (Plug-in Hybrid)
Hybrid with a larger rechargeable battery via mains plug. Electric range 40-80 km — daily use without petrol.
BEV (Battery Electric Vehicle)
100% electric vehicle: no combustion engine, 40-100 kWh traction battery, range 200-600 km.
Physical & installation
Polarity (positive right / left)
Position of the positive terminal (+) viewed from the front of the battery with terminals away from the user. Defines mechanical fit.
Terminal (post)
Electrical connection from the battery to the vehicle wiring. EN standard types: B0/B13/B19 (cars), F1/F2 (motorcycles), Stud (trucks).
Case / Box (L0-L6)
Standard EN physical dimensions. L0=175mm, L1=207mm, L2=242mm, L3=278mm, L4=315mm, L5=353mm, L6=394mm (length).
Maintenance & use
Sulphation
Crystallisation of lead sulphate on the plates when the battery spends time discharged. Reduces capacity irreversibly.
Smart charger
Microprocessor-controlled charger that detects battery type, SOC and applies optimal charge phases. Replaces basic chargers.
Trickle charger
Low-current charger (1-3 A) that keeps the battery at 100% indefinitely. For cars or motorcycles parked for months.
Standards & norms
EN 50342 (European SLI battery standard)
European standard that defines dimensions, capacities and specifications (CCA, Ah, RC) for lead-acid automotive batteries.
DIN (German battery code)
Traditional German 5-6 digit code summarising capacity and CCA. Example: 56519 ≈ 65 Ah / 540 CCA.
JIS (Japanese standard, the reference for motorcycle batteries)
Main coding for motorcycle batteries: YTX14-BS, FTX14-BS, TX14-BS. The first letter shows the manufacturer (Y=Yuasa, F=Furukawa) or may be absent.
K-Type / TecDoc
Unique identifier of a vehicle in the TecDoc database. Lets you find a 100% compatible battery without error.
Commercial
OEM (Original Equipment Manufacturer)
Brand that fits the car at the factory. Varta supplies many BMW/Audi/Mercedes; Tudor/Exide supplies Renault/PSA.
Equivalent / Compatible
Battery from a different brand than the OEM with identical specifications (Ah, CCA, technology, dimensions, polarity).
Service life of a battery
Average lifespan by technology: SLI 3-5 years, EFB 5-7 years, AGM 6-8 years. Warm climates cut 1-2 years.
Battery warranty
A battery warranty covers manufacturing defects, not service life. If a battery has worked correctly for months and then fails, the cause is most likely use or wear, not a factory defect.