Enersys Battery Bank Optimises Warehouse Space

Co-operative Food Retail Logistics called on Enersys to optimise the warehouse space at its distribution centre in County Durham by minimising the area required for charging warehouse-truck batteries. The solution was to build a three-tier battery bank - with potential to go even higher - served by an electric-powered changing cart. Over 90 per cent of the 2,000+ batteries used across the company's 19 warehouses are Hawker Evolution units. With a gelled electrolyte, Hawker Evolution offers a number of maintenance-free benefits because its sealed units require no topping up and there is no risk of spillage.

An efficient valve-regulated re-combination technology reduces gas emissions to an absolute minimum, which makes Evolution suitable for busy food-distribution operations. The best way of minimising the charge-area footprint was to create a bank of multiple tiers to accommodate the batteries on charge. Enersys devised a new version of the BBH with fully electric capability to remove any potential restrictions. Co-operative Food Retail Logistics was keen to build redundancy into the system to ensure it could maintain continuous warehouse-truck operations. The solution incorporated two identical banks, each with space for 42 batteries, arranged back to back with their own BBH.

This means that one of the systems can be taken offline for maintenance, while the other continues to supply charged batteries. An added advantage of this layout is that the central aisle running between the two banks allows engineers to check, monitor and maintain the chargers without entering truck-operating areas. This promotes safety and ensures essential maintenance work can continue without disrupting normal warehouse operations. The Pro-Series BBH is a semi-automated electric-powered change cart that runs on concealed rails alongside the row of chargers. When a change is required, the truck approaches the changing area and the driver disconnects its battery.

The trained member of staff dedicated to the battery area then takes over and completes change. A powerful extending electro-magnet on the BBH extracts the battery from the truck onto its onboard roller bed and then pushes it into place for charging. The device can be raised to handle batteries on the second and third levels in the charging banks. Co-operative Food Retail Logistics uses Enersys' Powertech HF chargers, said to offer energy efficiency as much as 20 per cent 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 and 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 per cent. To ensure maximum efficiency and performance from the power sources, all operations are overseen by the advanced Enersys Battery Management System. The 'intelligent' diagnostic software in the chargers transmits data via the system's PC 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.

There is no need to source two spare batteries for each truck because the balanced charging ensures that the equivalent of one spare is enough. The management system operates in conjunction with the remote monitoring and diagnostic Powernet service from Enersys. At any time, managers from Enersys can connect to the management system from their own sites and download a range of battery-related information. This allows them to analyse and assess overall performance and prepare reports for Cooperative Food Retail Logistics. Metrics available include battery status, batteries used, amps available, amps used, power usage, depth of discharge, charger faults by type and recent alarms. Engineers can also isolate individual batteries and carry out diagnostic tasks to identify specific problems.

Information can then be relayed to the warehouse's team of onsite engineers to help them carry out pre-emptive preventative maintenance. In addition to the battery systems, many other aspects of the site have been devised with sustainability in mind: the lighting automatically adjusts to match external conditions with reduced overall energy consumption; a seven-stage rainwater collection and filtration system provides water for use in staff toilets and vehicle washing;and packaging is returned to the site from stores for recycling in a state-of-the-art combined shredder and baler.