Expert Logistics, the UK’s leading white goods home delivery company, selected advanced Hawker® batteries, chargers and management systems from EnerSys® for the lift trucks at its new national distribution centre in Crewe. 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."
Expert Logistics distributes white goods for customers who include many of the biggest and best-known high street, multiple and internet retailers, including Appliances Online (owned by DRL Holdings), Tesco and Argos. The company offers an end-to-end service and aims to deliver items next day from stock direct to consumers on its customers’ behalf. Sustained growth led the company to assess its warehousing provision and consolidate multiple sites into ProLogis 360, a 360,000ft2 (33,445m2) facility in Crewe which opened in February 2012. The company anticipates that the advanced facilities will support its growth plans well into the future.
The 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.
"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 PlusTM 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 10oC. 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.
Battery charging is optimised using the latest-generation Hawker LifeIQTM 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."
The battery management system provides a wide range of information that the warehouse team uses to assess performance. This includes the number of completed battery changes, how many batteries were on charge and available for use at any time, when none were available, times of changes, and depth of discharge of batteries connected for charging. The trucks have also been fitted with tracking technology which allows the management team to understand truck operations with even more clarity. During the first few months of operation the system helped the warehouse management team to identify operational issues such as occasional over discharging which they were then able to rectify before this impacted on the long-term well-being of the batteries.
"The system manages battery utilisation very effectively and has already helped us understand operational issues such as under and over use," says Chris Adamson. "We know the batteries are being used evenly, that we have enough capacity to run the fleet and have good power management. The tracker system gives greater ownership to the staff who are then more responsible with their trucks."
Batteries are changed using a Hawker TuggerTM mounted onto Toyota powered pallet truck. The machine pulls up alongside the truck and pulls the depleted battery onto its built-in platform. The battery is placed into a free charging position and the designated fully-charged unit is transferred to the truck. This is simpler and safer than the previous warehouse where changes required a chain lifting rig.
"The whole operation only takes a few minutes and can be completed by one person with no lifting or stretching," says Chris Adamson.
EnerSys provided battery training to members of the 300+ warehouse team in conjunction with the on-site RTITB trainer. Toyota is responsible for all truck maintenance including topping up. The service engineer calls every morning to complete routine checks. One of the many advantages of the Perfect Plus batteries with the electrolyte circulation is that topping up is required much less frequently than with conventional batteries. The more efficient use of the batteries and the optimised charging regime should ensure prolonged performance with lower overall maintenance requirements and costs.
"We would expect the batteries to run for the full contract term of the trucks," says Chris Adamson.
To support the demanding service level commitment made by Expert Logistics the warehouse runs round the clock for 363 days a year. This invariably means that working patterns change throughout the day. The morning shift covers goods inward and stock replenishment tasks which means lots of bulk movements of stacked loads. Sortation ramps up during the day with a peak in the afternoon and early evening before the last loads are despatched at around 4am. The company runs its own fleet of delivery vehicles, including 65 double-decker trailers, which transport loads to its four regional bases to arrive from around 1am. This leaves enough time for items to be cross-docked onto the company’s fleet of 7.5 tonne vehicles for final delivery direct to customers the same day.
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