Typically, a fully charged lead acid battery discharges roughly 20% to 30% of its capacity in the first hour. The speed of power loss also depends on factors like temperature, age, and the load applied.
Do lead acid batteries need to be fully discharged?
Since that is no longer an issue (and never was an issue with lead acid batteries) there is not a need to fully discharge. By discharging a lead acid battery to below the manufacturer's stated end of life discharge voltage you are allowing the polarity of some of the weaker cells to become reversed.
How long should a lead acid battery stay discharged?
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.
How deep should a lead acid battery be discharged?
Discharging a lead acid battery too deeply can reduce its lifespan. For best results, do not go below 50% depth of discharge (DOD). Aim to limit discharges to a maximum of 80% DOD. This approach helps maintain battery safety, cycle life, and overall efficiency. Maintenance tips are essential for maximizing a lead acid battery's lifespan.
How to prevent damage while discharging a lead acid battery?
By understanding and implementing these practices, users can effectively prevent damage while discharging a lead acid battery and ensure its reliable performance. Discharging a lead acid battery too deeply can reduce its lifespan. For best results, do not go below 50% depth of discharge (DOD).
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.
It's best to immediately charge a lead acid battery after a (partial) discharge to keep them from quickly deteriorating. A battery that is in a discharged state for a long time (many months) will probably never recover or ever be usable again even if it was new and/or hasn't been used much.