A semi-traction battery, also known as a deep-cycle battery, is designed to be repeatedly deeply discharged and recharged. Unlike starter batteries that are primarily meant to deliver short bursts of power, semi-traction batteries can handle significant discharge.

The maximum depth of discharge of a semi-traction battery varies depending on the specific brand, model, and technical specifications of the battery. In general, semi-traction batteries are discharged to about 50-80% of their total capacity.

It is important to avoid fully discharging a semi-traction battery, as this can affect the battery's lifespan and performance. Regularly fully discharging the battery can reduce its capacity and damage it.

To optimize the lifespan of a semi-traction battery, it is often recommended to discharge the battery to about 50-80% of its capacity and then recharge it. By not fully discharging the battery, it maintains a good state and can perform better and have a longer lifespan.

Always refer to the manufacturer's instructions and recommendations for the semi-traction battery for specific information about the maximum depth of discharge and usage of the battery.