Question

What may happen if lead acid battery is over discharging?

Answer 1

If a lead-acid battery is over-discharged, it can cause several problems, both short-term and long-term. Here’s what may happen:

1. Sulfation: Over-discharging a lead-acid battery can cause the lead sulfate crystals on the battery’s plates to harden. This is known as sulfation. When the battery is discharged too much, these crystals don’t dissolve back into the electrolyte during charging, reducing the battery's capacity and overall efficiency.
   

1. Reduced Capacity: If the battery is over-discharged repeatedly, the chemical reaction inside the battery becomes less efficient. The battery will not be able to hold as much charge as it used to, resulting in shorter run times and less power output.
   

1. Permanent Damage: In extreme cases, over-discharging can cause permanent damage to the battery. The plates can warp or corrode, and the electrolyte can break down, leading to complete failure of the battery.
   

1. Voltage Drop: As a lead-acid battery discharges beyond its recommended level, the voltage can drop too low. This can cause the battery to stop providing power to the connected load, and in some cases, it might not be able to be recharged.
   

1. Overheating During Charging: If a battery is over-discharged, when you try to recharge it, it may take longer to charge, and the battery may overheat. This can further damage the internal components and reduce the lifespan of the battery.
   

Best Practice:

To avoid these issues, it's important to not discharge a lead-acid battery below a certain voltage (usually around 1.75–1.8 volts per cell). Using a battery monitor or a low-voltage disconnect system can help prevent over-discharging.

In summary, over-discharging a lead-acid battery shortens its lifespan, reduces capacity, and may cause permanent damage. Always try to keep the battery within its recommended charge range.