Qu'est-ce que la profondeur de décharge (DOD) ? Guide complet pour les batteries solaires
Depth of Discharge (DOD) explains how much energy you can safely use from a battery. Learn what DOD means, why it matters, and the best DOD level for LiFePO4 and solar batteries.
18/ 2025.Nov
What Is Depth of Discharge (DOD)?
Depth of Discharge (DOD) describes how much of a battery’s stored energy has been used. Example:
If a 10 kWh battery uses 5 kWh → DOD = 50%
If it uses 9 kWh → DOD = 90%
The higher the DOD, the more the battery has been discharged.
Why DOD Matters for Battery Life
A battery’s lifespan is closely linked to DOD.
Lower DOD = longer lifespan
Higher DOD = more stress on batteries
For example:
Lead-acid batteries:recommended DOD 30–50%
Lithium (LiFePO4) batteries:can safely reach 80–95% DOD
This is why lithium batteries last much longer than lead-acid.
How DOD Affects Cycle Life
Cycle life means how many times the battery can fully charge and discharge.
Type de batterie
Recommended DOD
Cycle de vie
Lead-acid
30–50%
300–600 cycles
NCM Lithium
70–80%
800–1,500 cycles
LiFePO4
80–95%
3,000–6,000+ cycles
LiFePO4 batteries are popular for solar systems because they maintain long cycle life even at high DOD.
State of Charge (SOC) vs DOD
100% SOC = 0% DOD
20% SOC = 80% DOD
Example: If the battery is 20% full, the DOD is 80%.
What Is the Best DOD for Solar Batteries?
For home energy storage and solar systems:
🔋 LiFePO4 (LFP) batteries:best DOD = 80–90%
Stable chemistry
Very long cycle life
Safe for deep discharge
🔋 Lead-acid batteries:best DOD = 30–50%
Deep discharge greatly shortens lifespan
Not ideal for daily solar cycling
How to Choose a Battery Based on DOD
When choosing a battery, look for:
Rated DOD (e.g., 80%, 90%, 95%)
Cycle life at that DOD
Warranty terms
Daily usage scenario
If you use the battery every day (solar system, backup system),choose a lithium battery with high DOD and long cycle life.
Real Example:10kWh Battery with 90% DOD
Usable energy = 10 kWh × 90% = 9 kWh
If the DOD was only 50% → usable energy = 5 kWh
Higher DOD gives more usable power and better efficiency.
Conclusion
Depth of Discharge (DOD) is a key factor in choosing the right solar battery. A higher DOD means more usable energy, but only lithium (especially LiFePO4) can handle high DOD while still keeping long lifespan.
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