Powering an intense application

The solution devised by EnerSys supports arduous round-the-clock operations while offering an ideal combination of performance, simplicity and energy efficiency.

“We were looking for a long-term commitment from a supplier that could work with us and our established lift truck partner to support our new operation and predicted growth plans,” says Chris Adamson, project manager at Expert Logistics who was responsible for commissioning the new facility. “EnerSys delivered a set of products that offered us a complete solution.”

The company’s previous distribution centre used gas powered counterbalance trucks but these were impractical for the new operation. Instead the company wanted to introduce clean and efficient electric powered equipment. Working with its long-standing partner Toyota the company specified a fleet comprising 22 counterbalance trucks with 1.0, 2.0 and 2.5 tonne capacities.

These are equipped with clamps to handle single and multiple items around the warehouse including the substantial block-stacking area for fast-moving lines such as fridges, washing machines and cookers. In addition, eight Toyota VNA clamp trucks operate in the 22 very narrow aisles with 33,000 locations reserved for slower selling items. The warehouse operates around the clock and the application is demanding which meant the choice of batteries was critical.

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“We assessed a range of potential suppliers and carried out extensive testing and modelling before selecting EnerSys,” says Chris Adamson.

The site is large and a key consideration was to ensure the batteries provided enough power to support shift-long performance. A trial carried out with a truck using a conventional battery was successful but the partners recognised that more powerful batteries would be better for the arduous workloads they expected.

EnerSys proposed its Hawker Perfect Plus range of advanced batteries which incorporate the Hawker Electrolyte Circulation System. This introduces an airflow into the battery which dissipates heat and moves the electrolyte continuously during charging so that it maintains a uniform specific gravity. The plates inside the battery are consequently charged more evenly and efficiently with no need for over-charging which would lead to increased gassing.

This improved efficiency and presence of the airflow helps to reduce battery temperatures by as much as 10 deg C. Charging times can be up to 30% shorter and energy consumption is reduced by up to 20% compared with conventional batteries. Minimised gassing and less sludging help to reduce water consumption by up to 70% which means topping up is required less often.

“These batteries seem to hold their charge for longer which is important because we need our trucks to work hard during every shift,” says Chris Adamson.

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Battery charging is optimised using the latest-generation Hawker LifeIQ high-frequency chargers. These are fully-programmable and offer improved efficiency and lower charging factor than conventional models which results in reduced energy consumption and lower carbon footprint. They automatically detect the battery’s level of discharge and only supply the amount of power needed to restore full charge, shutting down afterwards. This further reduces the mains power required leading to additional savings in electricity costs.

The batteries were supplied as a pool which effectively provides two units for each truck. Charging and changing is overseen by the advanced Hawker battery management system which communicates in real-time with the chargers to manage the entire process. Batteries can only be used when they are fully charged while the systematic rotation across the pool ensures balanced utilisation over time for life-long performance and reliability.

A screen at the end of the charging area clearly indicates the next battery to be retrieved for each type of truck. An alarm sounds if an operator disconnects the wrong battery from its charger. This overcomes the potential problem of operators simply taking the nearest available battery, regardless of its true state of charge. Operations are simplified further in this particular application because all of the counterbalance trucks, except for the lone 2.5 tonne model, use the same specification of battery.

“Most of the trucks have the same batteries which makes everything simpler,” says Chris Adamson. “An alarm sounds if we unplug the wrong battery which I really like.”

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