Batteries require maintenance work as stipulated by manufacturers and adapted to the special requirements of each installation. Not following these guidelines could result in:
- A reduction in design life.
- A reduction in useful capacity.
- Possibility of unexpected breaks in service.
The worst problem found in flooded batteries is when electrolyte level s to almost empty.
After 35 years in the business, we have only encountered this problem on two occasions, both under exceptional circumstances – where maintenance was non-existent or where there was a serious, undetected rectifier failure. This problem can lead to terrible results/outcomes.
Causes may include:
- Lack of maintenance: not adding water or not checking electrolyte level (only applies to batteries that need maintenance).
- High room temperature which results in electrolyte evaporation (not checking levels).
- Failure of equipment, causing battery to be overcharged indefinitely.
The consequences on a daily basis would be:
- Capacity reduction, since only a part of the plate would be working. In old batteries, this usually produces an overcharge (rectifier keeps trying to charge the battery after it has reached its nominal capacity), which contributes to high temperatures, so the problem gets worse.
- Unbalanced voltages in cells (middle cells get hotter as they cannot cool as effectively), including negative voltages cause overcharging, thus increasing heat and evaporation and further complicating matters.
- Corrosion on the part of the plate exposed to the air.
But the main problem arises when we need to perform a deep discharge. In this case:
- As the battery usually has good voltage (it’s normally overcharged), discharge begins without any problem.
- The current can only flow through the submerged part of the plate, producing high current density and causing significant heat in this lower part of the plate.
- This heat is transmitted from the plates to the tabs and from there to the post and terminals.
- The terminals heat the cell covers causing a fire.
Now we have a very dangerous and complicated situation:
- Even if the rectifier is disconnected, there is still voltage as part of the plate is always in contact with electrolyte.
- With electrolyte spills, voltage sources may appear at unexpected points, such as the metal racks/cabinets where the batteries are housed (structural voltage points).
- Gases produced when cell covers burn are extremely toxic and opaque, requiring the use of special breathing and lighting equipment when trying to extinguish the fire.
- And don’t forget, that all this is occurring during battery discharge, making it extremely probable that the rest of the plant will be experiencing various problems at the same time as they have run out of battery power.
In conclusion, to avoid these problems we recommend: