Batteries are part of almost all onboard vital systems as the backup power provider and the proper storage of batteries is crucial. The batteries themselves do not produce power but they provide the stored power which is produced during the charging phase by other power producers.
“The Port State Control code 04103: Emergency, lighting, batteries, and switches is one of the most common inspection deficiency codes marked worldwide and includes battery related items. Most of the findings are related to battery room and protective measures and missing equipment.”
The main types of batteries used on board are:
- Main battery backup system (in the battery room)
- Small batteries used on portable equipment
- Batteries for starting emergency generator and/or boats
For small batteries used on portable equipment and batteries starting emergency generator and boats, storage requirements are the common rules of battery use. Manufacturers’ storage requirements should be followed and the charging circuit should be checked to be free from the presence of dust/liquid as well as the cool temperatures that are needed in storage areas.
However, for the main battery system the storage requirements are detailed in SOLAS as batteries are regarded as hazardous risk sources on-board. On most ships the battery room is an isolated area on open deck. A battery room intended to accommodate the batteries of electric carts and trolleys being charged is a potentially dangerous area. Charging the batteries (particularly those made from lead acid) releases dangerous gases.
Construction guidelines for battery room
- A battery room environment must be dry and well ventilated.
- Charging equipment is to be free from dirt, overheating, loose connections and the indicators should function correctly.
- The ventilation arrangement for the battery locker should be inspected and checked. Battery installations of both lead acid and alkaline require good ventilation. The fans should be of the non-sparking type and should not produce any static charge.
- An independent exhaust fan is to be provided.
- The inlet duct should be below battery level with the outlet at the top of the compartment.
- The use of externally fitted lights or flameproof lights is essential.
- The paint used in the battery room and the materials for ducting should be corrosion resistant.
- All cables should be of adequate size so they can be well connected.
- The use of insulated spanners and plastic jugs for distilled water is necessary to prevent short circuit.
It is of key importance that the storage of batteries is not adjacent to the emergency switchboard. The battery room must not contain other systems related to the essential services of the ship. Pipes should not penetrate into the battery room as leakage of them may cause damage to or failure of the battery system. However, in the case of unavoidable installation of pipes, the pipe joints should be welded joints and flanges. Threaded joints or mechanical joints are not to be used.
A system should be installed to provide the following information into the engine room:
- The battery room temperature.
- The operating condition of the ventilation system in the battery room.
- The operating condition of the cooling system in the battery room.
The battery room temperature should be maintained at 15-25 °C. The door to the battery room should be kept closed at all times. An alarm signal should sound when the door is opened, or a self closing door should be installed. Steel works and decks adjacent to a lead acid battery should be painted with acid resistant paint.
Key equipment of the battery room
Apart from the aforementioned construction requirements, an on-board battery room should be equipped with the following for enhanced safety:
- An eye wash station.- Portable dry powder fire extinguishers or CO2 fire extinguishers of at least 5 kg capacity located near the battery room.
- Personal protection equipment (PPE) for testing and handling the batteries, including face shields or eyeglasses, chemical handling gloves, chemical resistant shoes or boots and a suitable apron. PPE must be stowed clear of the batteries to avoid possible contamination from battery acid.
- A “No Smoking/No flame/No naked light” sign should be posted outside the door.
- Electric resistance floor.
- A battery log to record checks, inspections and the batteries’ maintenance during intervals required by the Safety Management System and manufacturers’ instructions.
Key precautions during maintenance
During maintenance the following precautions should be taken to avoid risks and injury:
1. Battery Acid: Sulfuric acid in a battery is corrosive and can severely burn the skin or eyes, eat through clothing or even a concrete floor. Appropriate personal protective equipment (PPE) is essential when working on batteries or any UPS equipment.
2. Flammable gases: Batteries emit flammable hydrogen gas, especially during charge and discharge cycles. Hydrogen ignites easily and can cause a fire or explosion if allowed to accumulate in a small area. Hydrogen is not toxic, but at high concentrations is a highly explosive gas. In such concentration, all it takes is a source of ignition to cause an explosion. Sparking from a battery terminal as it is connected or disconnected from the charging system is more than adequate as a source of ignition energy. Check of adequate room ventilation should be undertaken.
3. Electrical Shock: Batteries are stored energy devices, meaning no overload protection is available if the battery is connected improperly or short-circuited. Always keep a voltmeter handy to verify correct polarity and expected voltage levels when connecting strings of batteries. Exercise caution when working with metallic tools or conductors to prevent short circuits and sparks. Remove rings, watches and loose jewellery when working with batteries. Never lay tools or other metal parts on top of a battery.
4. Battery Weight: Battery cells used on board can weigh anywhere from 20 to 50 plus pounds each. Use safe lifting techniques while exercising caution of electric shock. Do not attempt to stop a battery if it slides out of the equipment.
Maintenance guidelines for the storage of batteries
As with all systems on-board, batteries should also be checked for adequate operational condition and maintained if required. Inspections and maintenance intervals are needed as per the Safety Management System and manufacturers’ requirements.
Most generic items for maintenance are:
- Batteries are to be maintained in a full charge condition and charging circuit is always connected.
- Battery installation and its charging rectifier to be checked.
- Battery tops are to be clean and dry, and terminal nuts must be tight and a smear of petroleum jelly applied to prevent corrosion.
- Electrolyte should be at the proper level and shall have the correct value of specific gravity by checking with a hydrometer.
- Batteries are to be filled with distilled water as there is a loss of water during charging.
- Battery terminals should be smeared with petroleum jelly and should be kept clean.
- All metal tools used for maintenance should be plastic coated.