The majority of lift trucks used in warehouses and factories are battery powered. This means that battery handling – including charging and changing – can be one of the most important day-to-day tasks. Battery and lift truck suppliers have made great strides in recent years to ensure these routine procedures are carried out quickly, efficiently and above all safely.
Sooner or later a lift truck battery must be recharged. Charging in-situ can take too long in intensive applications and the only way to keep trucks running productively is to replace a depleted battery with a fully charged unit and recharge the original in a charging rack. In the past, batteries were lifted in and out by hand or with some kind of crane. Another way was to pull the battery off the truck by hand and push the replacement back in. Neither process is ideal and, as with any manual handling of large items, there was always a risk of accident or injury. Dropping batteries during change can also lead to acid spillage and the need for containment as well as damage to batteries, floors and related equipment.
Precise information about accidents and injuries related to battery handling is not readily available. Official sources, such as the HSE's RIDDOR, do not break the data into sufficient detail. Nevertheless the decline in overall accident and injury rates in recent years suggest improvements across all parts of industry.
Progress in truck and battery design made by OEM and battery manufacturers means there is no longer any need for manual lifting and handling. Most lift trucks now incorporate a battery compartment with side access and rollers in the floor while charging facilities have battery beds at the same height. The truck drives alongside a charging position, the depleted battery is rolled out and a fully charged replacement rolled back in. For larger vehicles with heavier and bigger batteries, the truck can incorporate mechanical assistance such as magnetic arm to move the battery into position. A special cart, ideally a specially designed battery change cart which typically also incorporates powered rollers and magnetic arms, can be used to transfer the battery if the truck cannot approach the charging station.
The move away from manual handling to semi- or fully-automated battery handling systems was driven by increasingly stringent manual handling regulations. These, and other health and safety legislation, have forced operators to reassess their operations. In particular the manual handling regulations called for operators to remove manual handling processes wherever possible. Although it is not mandatory to provide battery handling equipment to comply with current legislation, progressive operators recognise the resulting safety, reliability and performance benefits often make the investment worthwhile.
Many operators now choose to install dedicated areas where batteries can be charged and changed safely. These are ideally designed with a compact layout, efficient truck movement pathways, and safe parking zones. Tasks such as battery and charger management, battery changing and battery service should ideally be managed by dedicated operatives. If this proves impractical then fully-trained experienced drivers can carry out many of these functions while still significantly reducing any potential risks and hazards. Safety barriers can be installed to restrict access to non-authorised personnel and vehicles.
Good planning minimises truck movements and time spent in charging areas which is safer for operators, pedestrians and bystanders. Ideally the charging stations are arranged along aisles with the outer face towards the truck operating area. The inner face is configured for pedestrian access which removes potential points of contact between moving trucks and staff responsible for managing the installation so that routine checks and maintenance can be carried out safely. Whatever system is used the installation of equipment is important. Safe routing of DC cables on the chargers and the batteries will avoid damage and stop them becoming trip hazards.
Another safety consideration is the small risk of arcing during disconnection or connection when changing batteries. The latest-generation chargers incorporate circuitry and features including "Late Make, Early Break" plugs to minimise this risk. Ventilation systems remove gasses produced but these can be uneconomic in smaller warehouses or when charging stations are dispersed throughout larger sites. Batteries with "low gassing" can represent an ideal alternative.
The standards covering battery rooms and charging are EN50272. These are used as a reference by leading battery and truck manufacturers. Batteries themselves are considered articles under REACH regulation 1907/2006/EC which means they do not require a published safety data sheet. Manufacturers are, however, required to provide safety information on products in an MSDS document. This covers the safe use of batteries with details about composition, the electrolytes, potential hazards, transportation, end-of-life disposal and more. These documents do not generally cover the physical handling, charging or changing of batteries.