Why should you follow safety precautions when charging batteries?
Lead-acid batteries contain sulfuric acid. Only trained and authorized personnel should handle them. When talking about lead-acid batteries, people usually call sulfuric acid "battery acid" or the "electrolyte". An electrolyte is a general term used to describe a non-metallic substance like sulfuric acid or salts that can conduct electricity when dissolved in water.
Lead-acid batteries can produce explosive mixtures of hydrogen and oxygen gases when they are being charged. Note that in some cases, hydrogen gas has been found to interfere with carbon monoxide detectors. Check with your detector manufacturer(s) for more information.
- context Charge batteries only in approved, well-ventilated battery-charging areas.
- context Install a safety shower and an eyewash station in a battery-charging area.
- context Always follow the manufacturer’s instructions for safely charging the battery.
What are some precautions to use when watering a battery?
During the normal operation of a forklift with a flooded lead acid battery, the water in the electrolyte evaporates and needs to be refilled (watered) to keep the battery operating effectively and safely.
- context Develop procedures based on the manufacturer’s instructions on how and when to water the battery.
- context In general, a battery should be watered after it has been fully charged and cooled down.
- context Do not water a battery before or during charging, as the water may boil over and cause acid to leak.
- context Use distilled water (not tap water) to refill the electrolyte.
- context Never add sulfuric acid to the electrolyte.
- context Wear appropriate personal protective equipment (PPE) such as eye and face protection (e.g., chemical-resistant splash-proof goggles and face shield), and chemical-resistant gloves. Other personal protective equipment, such as a chemical-resistant apron and footwear, may also be necessary to protect against incidental exposure to the electrolyte. Do not store batteries in hot locations or in direct sunlight. Keep away from combustible and flammable items.
- context Use extreme care to avoid spilling or splashing the electrolyte. It can destroy clothing and burn the eyes and skin.
- context Make sure spill response equipment and personal protective equipment are readily available, and that spill response procedures have been developed.
- context Neutralize spilled or splashed sulfuric acid (electrolyte) with an appropriate neutralizing solution (e.g., baking soda solution), clean the spill area using spill response supplies (e.g., cleaning pads, disposable bags), and rinse the area with clean water. Make sure appropriate personal protective equipment is worn.
- context Dispose of contaminated items safely.
Why is there a danger of batteries exploding?
The charging of lead-acid batteries can be hazardous. When batteries are being recharged, they generate hydrogen gas that is explosive in certain concentrations in air (the flammability or explosive limits are 4.1% to 72% hydrogen in air). The spark-retarding vents help slow the rate of release of hydrogen, but the escaping hydrogen may form an explosive atmosphere around the battery if ventilation is poor. The ventilation system should be designed to provide an adequate amount of air exchange for the number of batteries being charged. This level of ventilation is essential to prevent an explosion.
- context Always keep sparks, flames, burning cigarettes, and other ignition sources away from the battery recharging area.
- context Wear protective eyewear when working near batteries.
- context Do not break "live" circuits at the terminals of batteries.
What should I do when charging batteries?
Natural exhaust ventilation: designed to limit the concentration of flammable gas to 25% of the lower explosive limit (LEL) during the worst-case scenario of charging all batteries at the same time.
Mechanical Ventilation: an exhaust ventilation rate that is effective at limiting the maximum concentration of hydrogen to 1% of the total volume of the room or area during a worst-case scenario when all batteries are being charged at the same time. Alternatively, having a ventilation rate based on the area of not less than 1ft3 / min / ft2 of the floor area of the room.
- context Check the electrolyte level before recharging. If the battery has been outside in cold weather, make sure that the battery is not frozen before recharging it.
- context Check the fluid level after the battery has been recharged. If the electrolyte covers the top of the plates, do not add more water. If water is added, use distilled water, not tap water.
- context Check that the battery ventilation holes or plugs are clear to allow hydrogen gas to escape.
- context When vent plugs need adjustment, follow the manufacturers' instructions carefully.
- context If the battery has sealed vents, do not recharge the battery with a current greater than 25 amps.
- context To reduce the possibility of explosions, follow the recommendations of the recharger manufacturer for attaching and removing cables and for operating the equipment properly. Generally, these recommendations include unplugging or turning off the charger before connecting or disconnecting the clamp connections. Carefully attach the clamps to the battery with the proper polarity (positive [+] clamp, usually red, to the positive terminal and negative (-) clamp, usually black, to the negative terminal).
- context Do not exceed the recommended charging time or overcharge a battery.
- context Only use charging devices that are manufacturer-approved and appropriate for the voltage and amp-hours (ah) of the battery.
- context Ensure that the area is ventilated when the batteries are being charged. Check the health and safety legislation, fire codes, and building codes that apply to your workplace. Guidelines for ventilation in battery charging areas, based on the National Fire Protection Agency Standards (NFPA 855), are provided below: