Depth of Discharge (DoD)
The quantity that expresses, as a percentage, the ratio of the energy drawn from a battery to its total capacity. When 50 Ah is taken from a 100 Ah battery the depth of discharge is 50%. In lead-acid and AGM service batteries it is widely recommended to keep this limit around 50% in order to preserve life.
Depth of discharge and state of charge are complements of each other: 30% DoD means 70% full. What matters chemically is how much lead sulphate has built up on the plates and how long it stays there. Deep discharge increases that build-up, and leaving the battery idle for a long time hardens the crystals.
The practical limits vary with chemistry. In lead-acid and AGM, 50% DoD is typically targeted in daily use, and short excursions to 70–80% are acceptable but should not become a habit. In LiFePO4, manufacturers permit markedly deeper use and the cycle life at the same depth is much higher.
In RV planning this ratio goes straight into the capacity choice. If your daily consumption is 60 Ah, about 120 Ah of nameplate capacity is needed on the lead-acid side. Short but high-current loads such as a levelling system increase the average consumption only slightly; their real effect is that on a weak battery they pull the voltage down temporarily and slow the jack movement.
Context in which this term is used: RV automatic levelling guide