Depth of discharge (DoD): What does it mean for your battery, and why is it important?

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A battery’s depth of discharge (DoD) indicates the percentage of the battery that has been discharged relative to the overall capacity of the battery. For example, if you have a Tesla Powerwall that holds 13.5 kilowatt-hours (kWh) of electricity, and you discharge 13 kWh, the DoD is approximately 96 percent.

The more frequently a battery is charged and discharged, the shorter its lifespan will be. It’s generally not recommend to discharge a battery entirely, as that dramatically shortens the useful life of the battery. Many battery manufacturers specify a maximum recommended DoD for optimal performance of the battery.

For example, if the manufacturer of a 10 kWh battery recommends a maximum DoD of 80 percent, you shouldn’t use more than 8 kWh from the battery without recharging. You can see why DoD is an important factor to consider: a higher DoD means you can use more of the energy being stored in your battery. Many modern lithium ion batteries these days advertise a DoD of 100 percent.

Your battery’s “cyclic life,” or the number of charge/discharge cycles in its useful life, depends on how much of the battery’s capacity you normally use. If you regularly discharge the batteries at a lower percentage amount, it will have more useful cycles than if you frequently drain the battery to its maximum DoD. For example, a battery may have 15,000 cycles at a DoD of 10 percent, but only 3,000 cycles at 80 percent DoD.

Below is a table of some of the more popular battery options, as well as the suggested maximum DoD as given

on the product’s detailed specification sheets.

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