Why Should Lead-acid Batteries, When Used As Backup Power For Uninterruptible Power Supplies, Be Avoided From Being Deeply Discharged (below 20%)?

When used as a backup power source in a uninterruptible power source system, lead-acid batteries are considered deeply discharged when their charge level drops below 20%. This state causes excessive lead sulfate crystals to form inside the grid and electrolyte, which are difficult to completely reduce during charging, leading to the permanent loss of active materials.

If lead-acid batteries are frequently subjected to deep discharge and recharge cycles, their usable capacity will significantly decrease, their cycle life will be shortened, and problems such as accelerated capacity decay and increased internal resistance may occur.

In a universal power supply battery backup system, the battery's health directly determines the duration and reliability of backup power. If remaining charge monitoring is neglected or no protection mechanism is implemented, causing the battery to frequently enter deep discharge, it may fail to output the expected power when restarting in a industrial ups power backup system.