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SESK: Stuff Everyone Should Know · sesk.info/eng-deep-discharge-dod

A battery discharge to at least what depth of discharge counts as a deep discharge?

80 percent DOD or more.

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  1. 20 percent
  2. 50 percent
  3. 80 percent ✔

Why: Depth of discharge is the share of capacity used up. Going to 80 percent or more is called deep discharge, and cycle life ratings are given for a specific DOD.

Huh, didn't know that: State of charge (SOC) is the opposite view: the share of capacity still left.

The dad joke
My battery hit 80 percent DOD. Now it's having a deep conversation with the charger.
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References

Answer: 80 percent. Depth of discharge is the share of capacity used up. Going to 80 percent or more is called deep discharge, and cycle life ratings are given for a specific DOD.

  1. MIT Electric Vehicle Team, A Guide to Understanding Battery Specifications web.mit.edu/evt/summary_battery_specifications.pdf
    A discharge to at least 80 % DOD is referred to as a deep discharge.
    Checked 2026-10-10.

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