Calculateur de Capacité Portante du Sol
Calculez la capacité portante du sol pour les fondations.
Total Battery Capacity
57.9 Ah
Total Battery Capacity vs Load Power
Formule
Battery Capacity Sizing
Battery capacity must account for the load, duration, efficiency losses, and depth-of-discharge limits.
Formula
Required Ah = (P / V) x Hours / Efficiency / DoD
where P is load power in watts, V is battery voltage, Hours is the backup duration, Efficiency accounts for inverter and wiring losses, and DoD is the maximum allowable depth of discharge (to protect battery life).
Exemple Résolu
500 W load on a 48V battery system for 4 hours, 80% DoD, 90% efficiency.
- 01Load current = 500 / 48 = 10.42 A
- 02Usable capacity = 10.42 x 4 / 0.90 = 46.3 Ah
- 03Total capacity = 46.3 / 0.80 = 57.9 Ah
- 04Battery energy = 57.9 x 48 / 1000 = 2.78 kWh
Questions Fréquentes
What depth of discharge should I use?
Lead-acid batteries: 50% DoD for long life. Lithium-ion (LFP): 80-90% DoD. Lithium NMC: 80% DoD. Deeper discharge shortens battery cycle life. Manufacturer datasheets show cycle count vs DoD curves.
How does temperature affect battery capacity?
Battery capacity decreases in cold temperatures. Lead-acid loses about 1% capacity per degree C below 25 deg C. Lithium-ion is less affected but still loses 10-20% at 0 deg C. Apply a temperature derating factor.
What battery voltage should I choose?
12V for small systems under 1 kW. 24V or 48V for 1-5 kW. 48V for 5-10 kW. Higher voltage means lower current for the same power, allowing smaller cables and lower losses.
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