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September 1st 2007

Hawker's zero-maintenance batteries give 20% higher work rate at Co-operative Retail Logistics

Co-operative Retail Logistics has specified EnerSys' Hawker Motive Power brand of batteries and chargers for the lift truck fleet at its new national distribution centre (NDC) in Coventry.

Hawker's Evolution high-performance sealed-gel batteries, which are completely maintenance free, are combined with 'intelligent' high frequency (HF) chargers linked to an IT-driven battery management system. This enables Co-op Retail Logistics to extract more than 20% more work out of the truck batteries each day than would have been possible with a conventional battery system.

"The Hawker package – high performance batteries and advanced battery management system, plus a high-speed automated battery-changing arrangement – means that the lift trucks can work harder for longer periods with minimum VOR time," explains warehouse manager Glyn Maude.

"That in turn makes a vital contribution to the productivity of the NDC." Co-operative Retail Logistics, until recently known as ACC Distribution, officially opened the 30,000 sq m greenfield site Coventry NDC in the summer last year as part of a move to rationalise operations by separating slow- and fastmoving stock items and processing them through different dedicated centres.

The Coventry site now holds more than 80% of the Co-op's slow-moving stock, around 7500 lines including ambient groceries and wines and spirits, which it supplies to all Co-op stores nationwide via transhipment to its own regional distribution centres and other independent Co-operative society depots. The NDC also delivers direct to around 25 stores in the region. Currently the site, which has around 40,000 pallet locations and 3500 ground-level pick faces, receives up to 3000 pallet loads of goods from suppliers each day and, working round the clock, despatches more than a million picked cases a week.

The Hawker batteries are used for the NDC's large lift truck fleet which, when fully up to strength, will comprise 23 reach trucks, 123 low-level order pickers, 12 powered pallet transporters and three electric counterbalance trucks. Most of the trucks use Hawker's Evolution high performance sealed gel electrolyte batteries. Evolution requires no topping-up throughout its life, and its highly efficient valve-regulated re-combination technology reduces gas emissions to a minimum. Coop Retail Logistics has therefore avoided the necessity of committing heavy investment to building a special vented charging room.

Hawker has installed a dedicated battery charge/change area within the warehouse, comprising 300 charging stations in two separate three-level banks.

Co-op Retail Logistics is a pioneer in the move to triple-level battery charging and has also installed this configuration at its Thurrock depot.

Battery changing is undertaken with Hawker's Pro-Series BBH semi-automated change cart. This electrically driven device runs on concealed rails between the rows of chargers, using a powerful extending electro-magnet to extract the battery from the truck onto its on-board roller bed and then push it into place for charging.

The BBH can be raised to handle the batteries on the second and third levels in the charging banks. The whole battery change process is a very quick and simple one-man job, which again helps sustain truck uptime, and involves no potentially injurious manual handling.

Co-op Retail Logistics uses Hawker's Powertech HF chargers, which offer outstanding energy efficiency, as much as 20% higher than 50Hz chargers. The chargers automatically detect the battery's level of discharge and will supply only the amount of power needed – and no more – to restore full charge. This means less mains power is required to charge a battery. Thus the energy costs per charge are considerably reduced, leading to significant savings in electricity costs. With the Evolution battery these savings can be as much as 30%.

The Coventry NDC also has Hawker's Battery Management System. The 'intelligent' diagnostic software in the Powertech chargers transmits data to a large display screen installed in the battery changing area. The display clearly indicates the order in which batteries, for each type of truck, should be retrieved, ensuring that only fully-charged units are taken. This makes certain that all batteries receive the correct amount of charge before being used, and that the batteries are systematically rotated, overcoming the potential problem of operators simply taking the nearest available battery, regardless of its true state of charge.

"The system ensures that all batteries always receive the correct charge, and that they are used in the right order," says Glyn Maude. "This means we always get optimum performance out of each battery – as much as 20% more work each day.

The efficiency of the battery management system also enables us to slash the total number of batteries needed to operate the fleet round the clock." Another benefit of the Hawker Battery Management System is its ability to recognise different battery types and technologies. "This has been a huge advantage in the early days of the new site when we were using a lot of different types of trucks on short term hire, waiting for the new fleet to come up to strength," says Glyn Maude. "The system recognised up to five different kinds of battery in use on the short term hire trucks."

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