# RC (Reserve Capacity)

> Minutes the battery delivers 25 A while staying above 10.5 V. Measures autonomy with engine off or alternator failed.

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

## Definition

RC (Reserve Capacity) indicates how many minutes the battery can deliver a continuous 25 A without the voltage dropping below 10.5 V, starting from 100% charge at 27°C. **It is the key figure for knowing how long consumers will last with the engine off** (radio, navigation, hazard lights) or if the alternator fails on the road. A typical mid-range car battery has 90-150 minutes of RC; premium batteries (deep cycle, large AGM) reach 180-220. Approximate conversion: RC × 0.6 ≈ Ah (not exact). The EN standard does not require it as a primary specification (it prioritises CCA and Ah) but the American SAE/BCI highlight it. For users of **motorhomes, boats or vehicles with many electrical accessories** RC is more relevant than CCA.

## See also

- [Ah (Amp-hour)](https://baterias.com/gb/battery-glossary/ah)
- [CCA (Cold Cranking Amps)](https://baterias.com/gb/battery-glossary/cca)
- [Deep cycle](https://baterias.com/gb/battery-glossary/deep-cycle)

---
[Back to glossary](https://baterias.com/gb/battery-glossary)