Depth of Discharge (DOD)
Definition
Percentage of battery capacity that has been discharged relative to total capacity. 80% DOD means 80% of capacity used, 20% remaining.
Why It Matters
- Cycle life increases dramatically with reduced DOD
- Operating at 50% DOD can double or triple cycle life vs. 100% DOD
- Practical systems often limit DOD to 80% for longevity
- Related to state-of-charge: SOC = 100% - DOD
Common Pitfalls
- Not considering usable capacity vs. total capacity
- Not communicating DOD limits to users/operators
- Ignoring voltage window restrictions at temperature extremes
- Not optimizing DOD vs. cycle life tradeoff for application