Discharging batteries is entirely a function of your particular application. However, below is list of helpful items:
1. Shallow discharges will result in a longer battery life.
2. 50% (or less) discharges are recommended.
3. 80% discharge is the maximum safe discharge.
4. Do not fully discharge flooded batteries (80% or more). This will damage (or kill) the battery.
5. Many experts recommend operating batteries only between the 50% to 85% of full charge range. A periodic equalization charge is a must when using this practice.
6. Do not leave batteries deeply discharged for any length of time.
7. lead acid batteries do not develop a memory and need not be fully discharged before recharging.
8. Batteries should be charged after each period of use.
9. Batteries that charge up but cannot support a load are most likely bad and should be tested. Refer to the Testing section for proper procedure.