Lead acid batteries should never stay discharged for a long time, ideally not longer than a day. It's best to immediately charge a lead acid battery after a (partial) discharge to keep them from quickly deteriorating.
Ideally you can configure the cut-off coltage, such as with the depicted unit. So many lead acid batteries are 'murdered' because they are left connected (accidentally) to a power 'drain'. No matter the size, lead acid batteries are relatively slow to charge. It may take around 8 - 12 hours to fully charge a battery from fully depleted.
Personally, I always make sure that anything connected to a lead acid battery is properly fused. The common rule of thumb is that a lead acid battery should not be discharged below 50% of capacity, or ideally not beyond 70% of capacity. This is because lead acid batteries age / wear out faster if you deep discharge them.
The common rule of thumb is that a lead acid battery should not be discharged below 50% of capacity, or ideally not beyond 70% of capacity. This is because lead acid batteries age / wear out faster if you deep discharge them. The most important lesson here is this:
This means that if you (accidentally) short-circuit a lead acid battery, the battery can explode or it can cause a fire. Whatever object caused the short-circuit, will probably be destroyed. Because lead acid batteries can supply such high currents, it's important to assure that you use the right wire thickness / diameter.
Proper maintenance of sealed lead-acid batteries involves regular charging and discharging cycles, keeping the battery clean and dry, and avoiding exposure to extreme temperatures. It is also important to check the battery’s voltage regularly and to replace it when necessary. What is the charging and discharging process of lead acid battery?