My Forklift Battery Smells like Rotten Eggs
WHAT’S HAPPENING?
As we know, these batteries are filled with an electrolyte of water and sulfuric acid. When you smell that rotten egg odor, the battery is heating up so much that the sulfuric acid (H2SO4) is being converted into a gas called Hydrogen Sulfide (H2S). This does not happen when a battery is working properly. Normally when a battery is charged, some of the water in the electrolyte is lost through electrolysis where H2O is turned into Hydrogen Gas (H2) and Oxygen.
IS HYDROGEN SULFIDE BAD FOR PEOPLE?
Short answer: yes. At low levels of concentration, Hydrogen Sulfide smells like rotten eggs. At extremely high levels of concentration, Hydrogen Sulfide can result in unconsciousness or even death. Even at low levels of concentration, Hydrogen Sulfide can irritate the eyes, nose, throat, and respiratory system. If your battery is smelling like rotten eggs, it is best to pull it from service immediately and have a professional test the battery and recommend next steps.
WHAT CAUSES A BATTERY TO SMELL LIKE ROTTEN EGGS?
In order to understand why your battery smells, we need to review how a battery is supposed to work. When the battery is charged, the lead plates and the electrolyte turn the electrical energy from the charger into chemical differences between the positive and negative plates. In other words, electrical energy is stored as chemical energy.
When you discharge the battery, the chemical energy is released and returned back to electrical energy to power your forklift. Charging and discharging depend on having healthy positive and negative plates that can store the chemical energy. Over time, however, the plates become less able to store chemical energy. When the plates can no longer store chemical energy, the current from the charger can’t go anywhere and it is converted into heat. This is what causes the cells to heat up and bake the sulfuric acid into hydrogen sulfide.
WHAT SHOULD I DO IF I SMELL ROTTEN EGGS?
Immediately pull the battery out of service. There is at minimum one bad cell in the battery. Continuing to use the battery in its current state does two things:
- Puts excessive strain on the other cells and causes other cells to fail
- Emits dangerous hydrogen sulfide gasses into your work environment
A professional battery service can test the battery and determine how many cells have failed. Based on a variety of factors (age, make, condition, capacity), the service provider should be able to help you decide whether it makes good financial sense to repair the battery or replace it.