What is Depth of Discharge (DoD)?

Different battery types have varying tolerances for DoD, impacting their cycle life and use cases. Here’s a comparison of common battery types and their discharge depths:

• Lead-Acid Batteries:

The recommended DoD is around 50% to extend cycle life. Frequent deep discharges (80% or more) can drastically shorten the lifespan, making lead-acid batteries suitable for medium-frequency charge-discharge applications.

• Lithium-Ion Batteries:

They typically allow a DoD of 80% to 90% and, in some cases, 100%. They can maintain a longer cycle life even under high DoD, making them ideal for applications requiring high energy density and long endurance, such as portable electronics and electric vehicles.

• LiFePO4 Batteries:

These batteries can also achieve 80% to 100% DoD while maintaining excellent cycle life, often over 2000 cycles. With their higher safety and durability, they are well-suited for commercial battery energy storage systems.

• Nickel-Metal Hydride (NiMH) Batteries:

The recommended DoD is around 70% to 80%, as over-discharge can accelerate capacity loss. NiMH batteries are often used in hybrid vehicles and household appliances for moderate-frequency charging applications.

• Solid-State Batteries:

These emerging batteries offer high DoD levels, over 90%, while maintaining extended lifespan. Due to their high safety and energy density, solid-state batteries are seen as an ideal future choice for EVs and portable devices.