# 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.

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

## Definition

AGM (Absorbent Glass Mat) is a lead-acid battery technology in which the electrolyte is absorbed into a fibreglass mat between the plates. This construction makes the battery sealed (no maintenance of fluid levels required), vibration-resistant and able to handle far more demanding cycling than a flooded SLI. The cycling protocols defined in EN 50342-6/-7 confirm a much longer service life than a conventional battery, especially under Start-Stop use. AGM is **mandatory in vehicles with Start-Stop and regenerative braking** (present in many European premium models since the late 2000s and in mainstream cars from the mid-2010s) because it tolerates hundreds of microcycles per day. Typical models: Varta E11 (80 Ah AGM), Bosch S5 A11, Exide EK800. Usually costs 1.5 to 2 times the price of an equivalent EFB.

## See also

- [EFB (Enhanced Flooded Battery)](https://baterias.com/gb/battery-glossary/efb)
- [GEL (Gel battery)](https://baterias.com/gb/battery-glossary/gel)
- [Start-Stop](https://baterias.com/gb/battery-glossary/start-stop)
- [Regenerative braking](https://baterias.com/gb/battery-glossary/regenerative-braking)

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