The condition of charge of batteries (secondary cells) should be tested on a regular basis. GMDSS regulations stipulate that the voltage of any secondary batteries should be read and recorded each day and in the case of lead/acid batteries, the specific gravity of the electrolyte should be measured and recorded each month.
The crew should be aware of which equipment contains batteries (primary cells) and they should be checked regularly for leakage and must be replaced in accordance with the expiration dates given by the manufacturers. Spares should be carried on board.
Replacing batteries
Batteries have to be correctly connected into the circuit due to the terminals having either positive or negative polarity. Positive terminals should be connected to positive equipment connections and negative terminals should be connected to negative equipment connections.
Connecting the wrong way round is likely to damage both the battery and the equipment.
Charging batteries (secondary cells)
Batteries should be recharged according to the manufacturer's recommendations.
When charging batteries the correct polarity must be observed as well. When connecting a portable charger, the red or positive lead from the charger must go to the positive terminal and the black or negative lead from the charger must go to the negative terminal. Connecting the charger the wrong way round will damage the battery, it could even cause an explosion.
Recommendations on battery care and maintenance
- Batteries should be kept clean and dry.
- Batteries should be kept in a purpose designed battery box that will not allow battery content to pour out under any circumstances.
Only for secondary cells:
- The battery bank should be adequately secured because batteries are heavy and may be dangerous to the crew and the vessel if they get loose in the event of a knockdown.
- Signs of corrosion on batteries and near them should be regulary checked.
- The top of the battery and the terminals should be kept clean. This will prevent stray currents flowing between the terminals and flattening the battery.
- The battery terminals can be protected from corrosion by applying a thin coat of petroleum jelly.
- The vessel’s batteries are usually kept in the bilge where the weight is low down, but this makes them very vulnerable in case of flood or fire. This is an argument for having a dedicated radio battery higher up in the vessel where it is more protected.
Only for lead/acid batteries (secondary cells):
- Lead/acid batteries should be kept in a purpose designed battery box that will allow the flammable hydrogen gas to escape but not allow sea water to get in.
- The electrolyte level should be regularly checked in lead/acid batteries. Only distilled water should be used when topping up the electrolyte, otherwise impurities will be added which will drastically shorten the life of the battery.
- During the charging cycle of lead/acid batteries, when hydrogen gas is given off, the area should be well-ventilated and crew must not smoke in the vicinity.
- Great care must be taken when handling the sulphuric acid electrolyte of lead/acid batteries. A sensible precaution would be to wear rubber gloves, old clothing and safety goggles.