There are several reasons behind failure of lead acid battery much earlier than expected. Some major reasons are elaborated here which cover both sealed lead acid (SLA) battery and flooded (wet) lead acid battery.
1- Quality of Battery
Quality of battery is majorly responsible for its life span. A good quality lead acid battery can last much longer than a cheaper battery. This is because material used inside battery is refined and purified to certain grades of quality.
2- Usage of Battery
Life span of a lead acid battery is also dependent upon how much it is used. Lead acid battery has several hundreds charge-discharge cycles. Batteries wear out faster when used too much.
3- Charger Quality
There are different kinds of battery chargers, 2 stage, 3 stage etc. A poor charger can destroy the battery faster than anything else. Always use good quality chargers and UPS to increase life of battery. Preferably use SLA batteries with UPS.
4- Overcharging Battery
Overcharging any rechargeable battery is extremely fatal for it. Overcharging leads to corrosion of battery plates which results in premature failure. Getting too much hot is an indication that battery is getting overcharged. Lead acid batteries which has worn out often get overcharged because charging cut off voltage is not attained.
5- Deep Discharging BatteryNot only lead acid batteries, deeply discharging any rechargeable battery is extremely damaging for its health. Due to deep discharge, battery losses its actual capacity and efficiency.
6- Poor Maintenance
SLA batteries are maintenance free but flooded lead acid batteries require regular maintenance i.e. topping up cells with distilled water and cleaning. If not maintained, flooded lead acid battery slowly losses water. If plates get dried, then there is no reversal for failure of battery.
7- Wrong Gravity Of Electrolyte
If gravity of electrolyte is not correct, battery works but losses its actual capacity faster over time. Gravity of SLA batteries can not be tested but if you have flooded lead acid battery, its gravity can be tested using hydrometer.
8- Shorted Battery Cells
Battery cells short if separators between positive and negative plates fail. Sometimes, shedding from battery plates which is settled at battery bottom if rise too much and start touching battery plates, battery plates short resulting in failure of battery.
9- Cracks in Battery Plates
Sometimes, vibrations caused by vehicle lead to cracks and breakage of charging plates resulting in abrupt failure of battery. Connections inside battery can also go loose due to excessive vibrations.
10- Some Other Reasons For Failure
– Breaking of battery posts
– Leakage of electrolyte through cracks.
– Sulphation due to prolonged zero charge state.