Autonomie Audit Suite
Prévoyez précisément combien d'heures votre parc de batteries soutiendra vos charges avant d'atteindre des niveaux de décharge critiques.
Données de Charge et de Batterie
Capacité du Parc et Consommation
Le résultat se met à jour en temps réel au fur et à mesure que vous saisissez les paramètres.
La Formule d'Autonomie
L'autonomie de la batterie est déterminée par la quantité d'énergie stockée, la vitesse à laquelle elle est consommée et la profondeur de décharge autorisée.
Calcul de l'Autonomie
Hours = (Ah × V × DoD) ÷ Watts Multipliez la capacité de la batterie (Ah) par la tension pour obtenir des Wh, appliquez le DoD pour obtenir l'énergie utilisable, puis divisez par la charge en watts pour obtenir l'autonomie.
Énergie Utilisable
Usable Wh = Ah × V × DoD Toute l'énergie stockée n'est pas accessible — le DoD limite la profondeur de décharge possible sans endommager la batterie ni raccourcir sa durée de vie.
How to Calculate Battery Runtime
Battery runtime tells you how long a battery bank can power a given load before needing a recharge. This calculation is critical for sizing backup power systems, off-grid solar storage, portable power stations, and UPS systems. The key variables are battery capacity (Ah), system voltage, Depth of Discharge (DoD), and the power draw of connected loads.
Why Peukert's Law Matters for Large Loads
Peukert's Law states that lead-acid batteries deliver less total energy when discharged at higher rates. A 100Ah battery discharged in 1 hour may actually deliver only 55–60Ah. This effect is minimal in lithium batteries but significant in lead-acid. For critical applications, use the C-rate adjusted capacity from your battery datasheet rather than the nominal Ah rating.
DoD Limits by Battery Chemistry
- Flooded Lead-Acid: Maximum safe DoD is 50%. Going deeper dramatically accelerates sulfation and plate degradation — expect 300–500 cycles at 50% DoD.
- AGM / Sealed Lead-Acid: Slightly better at 60–80% DoD depending on the manufacturer's rating. Maintenance-free but less tolerant of overcharging.
- Lithium Iron Phosphate (LiFePO4): Safe to 80–90% DoD with 2,000–5,000+ cycles at that depth. Best long-term value despite higher upfront cost.
- NMC / NCA Lithium: Used in EVs and some portable packs. Higher energy density than LiFePO4 but less thermally stable and typically limited to 80% DoD for longevity.
Sizing for Backup Power
- Define the Load: List all devices that must run during a power outage. Include their wattage and expected hours of operation.
- Calculate Total Wh: Sum all load × hours to get total watt-hours needed per outage event.
- Apply DoD Factor: Divide required Wh by your battery's DoD to get the required gross capacity.
- Convert to Ah: Divide gross Wh by system voltage to get required Ah.
- Add a Safety Buffer: Design for 80% of nominal capacity to account for aging — a battery that starts at 100% capacity will degrade to ~80% over its useful life.