# 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).

**URL canónica**: https://baterias.com/gb/battery-glossary
**Idioma**: en-GB

## Technologies

- [AGM (Absorbent Glass Mat)](https://baterias.com/gb/battery-glossary/agm) — Battery with electrolyte absorbed in a glass fibre mat. Lifespan roughly double that of a conventional battery. Required for advanced Start-Stop.
- [EFB (Enhanced Flooded Battery)](https://baterias.com/gb/battery-glossary/efb) — 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)](https://baterias.com/gb/battery-glossary/gel) — Lead-acid with gelled electrolyte. Specialised for deep cycle use: boats, mobility scooters, solar systems, caravans.
- [SLI (Starting Lighting Ignition)](https://baterias.com/gb/battery-glossary/sli) — Conventional starting battery, flooded lead-acid. Not suitable for Start-Stop. Typical service life 3-5 years.
- [Lead-acid battery](https://baterias.com/gb/battery-glossary/lead-acid) — Base technology for automotive batteries: lead plates + sulphuric acid electrolyte. Invented by Planté in 1859.
- [Deep cycle](https://baterias.com/gb/battery-glossary/deep-cycle) — Battery designed for repeated deep discharges. Uses: marine, solar, caravans, mobility scooters.
- [LFP / LiFePO4 (Lithium Iron Phosphate)](https://baterias.com/gb/battery-glossary/lfp) — Lithium iron phosphate battery: 4-5× longer service life than lead-acid, half the weight, no fire risk.

## Technical specifications

- [CCA (Cold Cranking Amps)](https://baterias.com/gb/battery-glossary/cca) — Current the battery can deliver at -18°C for 30 seconds while keeping above a minimum voltage. Determines cold-start capability.
- [Ah (Amp-hour)](https://baterias.com/gb/battery-glossary/ah) — 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)](https://baterias.com/gb/battery-glossary/voltage) — Potential difference between terminals. Automotive standard: 12 V (6 cells × 2.0 V). Trucks: 24 V (12 cells).
- [RC (Reserve Capacity)](https://baterias.com/gb/battery-glossary/rc) — 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)](https://baterias.com/gb/battery-glossary/c20) — Standard discharge rate: C20 = discharge the battery in 20 h. It is the reference used to publish nominal Ah.
- [SOC (State of Charge)](https://baterias.com/gb/battery-glossary/soc) — Charge state in %. 100% = full battery; 0% = empty. Estimated by reading open-circuit voltage at rest.
- [DoD (Depth of Discharge)](https://baterias.com/gb/battery-glossary/dod) — Depth of discharge: % of capacity consumed. 50% DoD = battery has 50% capacity remaining.
- [SOH (State of Health)](https://baterias.com/gb/battery-glossary/soh) — Battery health: current capacity vs nominal. 100% = new battery; 70-80% = end of practical service life.

## Vehicle features

- [Start-Stop](https://baterias.com/gb/battery-glossary/start-stop) — System that switches off the engine at stops (traffic lights) to save 5-15% fuel. Requires EFB or AGM battery.
- [Regenerative braking](https://baterias.com/gb/battery-glossary/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)](https://baterias.com/gb/battery-glossary/mhev) — Light hybrid system with a secondary 48 V network that assists the engine on acceleration and recovers energy on braking.
- [HEV (Full Hybrid)](https://baterias.com/gb/battery-glossary/hev) — 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)](https://baterias.com/gb/battery-glossary/phev) — Hybrid with a larger rechargeable battery via mains plug. Electric range 40-80 km — daily use without petrol.
- [BEV (Battery Electric Vehicle)](https://baterias.com/gb/battery-glossary/bev) — 100% electric vehicle: no combustion engine, 40-100 kWh traction battery, range 200-600 km.

## Physical & installation

- [Polarity (positive right / left)](https://baterias.com/gb/battery-glossary/polarity) — Position of the positive terminal (+) viewed from the front of the battery with terminals away from the user. Defines mechanical fit.
- [Terminal (post)](https://baterias.com/gb/battery-glossary/terminal) — 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)](https://baterias.com/gb/battery-glossary/case) — Standard EN physical dimensions. L0=175mm, L1=207mm, L2=242mm, L3=278mm, L4=315mm, L5=353mm, L6=394mm (length).

## Maintenance & use

- [Sulphation](https://baterias.com/gb/battery-glossary/sulphation) — Crystallisation of lead sulphate on the plates when the battery spends time discharged. Reduces capacity irreversibly.
- [Smart charger](https://baterias.com/gb/battery-glossary/smart-charger) — Microprocessor-controlled charger that detects battery type, SOC and applies optimal charge phases. Replaces basic chargers.
- [Trickle charger](https://baterias.com/gb/battery-glossary/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)](https://baterias.com/gb/battery-glossary/en-50342) — European standard that defines dimensions, capacities and specifications (CCA, Ah, RC) for lead-acid automotive batteries.
- [DIN (German battery code)](https://baterias.com/gb/battery-glossary/din) — Traditional German 5-6 digit code summarising capacity and CCA. Example: 56519 ≈ 65 Ah / 540 CCA.
- [JIS (Japanese standard, the reference for motorcycle batteries)](https://baterias.com/gb/battery-glossary/jis) — 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](https://baterias.com/gb/battery-glossary/tecdoc) — Unique identifier of a vehicle in the TecDoc database. Lets you find a 100% compatible battery without error.

## Commercial

- [OEM (Original Equipment Manufacturer)](https://baterias.com/gb/battery-glossary/oem) — Brand that fits the car at the factory. Varta supplies many BMW/Audi/Mercedes; Tudor/Exide supplies Renault/PSA.
- [Equivalent / Compatible](https://baterias.com/gb/battery-glossary/equivalent) — Battery from a different brand than the OEM with identical specifications (Ah, CCA, technology, dimensions, polarity).
- [Service life of a battery](https://baterias.com/gb/battery-glossary/service-life) — Average lifespan by technology: SLI 3-5 years, EFB 5-7 years, AGM 6-8 years. Warm climates cut 1-2 years.
- [Battery warranty](https://baterias.com/gb/battery-glossary/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.