Technical glossary of key terms about lead-acid, AGM, EFB, LiFePO4 batteries and Start-Stop systems. Clear definitions so you know exactly what your vehicle needs.
Ah unit
Ampere-hour: capacity unit of a battery. A 70 Ah battery delivers 70 A for 1 hour (or 7 A for 10 hours). Higher Ah = more autonomy and accessories without recharging.
CCA A
Cold Cranking Amperes: maximum current the battery delivers at -18 °C for 30 seconds maintaining at least 7.2 V. This determines if your car starts in winter. Small car: 400-540 A. Large/diesel: 700-900 A.
AGM technology
Absorbent Glass Mat: technology where the electrolyte (acid) is absorbed in fiberglass mesh. Lasts up to 3× more cycles than conventional, handles extreme heat (Costa del Sol) and doesn't leak. Mandatory in Start-Stop cars with regenerative braking.
EFB technology
Enhanced Flooded Battery: reinforced lead-acid battery for basic Start-Stop systems without regenerative braking. Mid-range between conventional and AGM. 2× more cycles than conventional, cheaper than AGM.
Start-Stop system
System that automatically stops the engine when the vehicle halts (traffic light, jam) and restarts it. Reduces fuel and emissions but submits the battery to 30-80 starts/day. Requires specific AGM or EFB battery.
BMS electronics
Battery Management System: ECU that manages battery charging in modern cars. After replacing a battery in a BMS car, the new one must be coded into the ECU via OBD-II; otherwise the alternator won't charge at the right voltage and the battery lasts months instead of years.
LiFePO4 chemistry
Lithium iron phosphate: lithium battery chemistry with the best thermal safety (no thermal runaway like NMC). Weighs 1/3 of equivalent lead-acid, allows 80-90% DoD useful, lasts 4-5× longer. Ideal for motorhomes, marine and service applications.
SoH metric
State of Health: percentage of original capacity the battery still holds. New = 100%. Below 60-70% normally requires replacement. Measured with professional Midtronics equipment (5 minutes, free at Málaga Baterías).
DoD metric
Depth of Discharge: how deep the battery is discharged. AGM: 50-60% max for long life. LiFePO4: 80-90% with no damage. A starter battery must NOT be deeply discharged (shortens life); for that, use cyclic or service batteries.
DIN / EN standard
European standards (EN 50342) that standardise dimensions, CCA and capacity of starter batteries. The case (L0, L1, L2, L3, L4, L5, L6) is the physical size; the alphanumeric code (E11, H3, F17...) indicates the commercial reference within the standard.
Sulfation degradation
Formation of lead sulfate crystals on the internal plates when the battery stays discharged. Irreversible if it lasts weeks. That's why a battery left in a parked car for months may become useless even if new.
Recycling legal
Batteries are hazardous waste. In Spain they must be collected by authorised managers under RD 106/2008 and the Regulation (EU) 2023/1542. At Málaga Baterías we collect and recycle your used battery for free with your new one.