User report: Charge cooler, drive further

Big Dutchman's logistics centre is bustling with activity this Monday morning: large automatic roller shutters are opening and closing almost every second and forklift trucks in various sizes, shapes and colours are whirring through the numerous aisles, generating a background noise resembling an oversized beehive. Meanwhile several HGVs wait outside to be loaded or emptied. “Up to 50 lorries arrive here daily,” says Bernd Gürtler who, as Senior Manager of Logistics Services, is responsible for the smooth flow of materials in the warehouse. “In order to handle this volume of goods quickly and efficiently, we need efficient and reliable technology.”

Big Dutchman AG specialises in animal housing and feeding systems for modern pork and poultry production. In 1938, the company's founder invented the world's first automatic feeding system in Holland, Michigan (USA). Since then the family company's portfolio has expanded to include simple systems, computer-controlled feeding systems with climate control, exhaust air treatment and waste recycling equipment, as well as hardware and software for the management of pig breeding and fattening plus poultry and egg production. Big Dutchman is active in over 100 countries spanning five continents, and is the global market leader in its industry with a turnover of 688 million euros in 2014.

New logistics centre for increasing demand

The company has been based in Vechta-Calveslage in Lower Saxony since 1985. Roughly 800 of the 2,500 global workforce are employed here, a quarter of whom work in logistics. “Our customers range from farmers who still like to visit us on their tractors, to large-scale enterprises with several million animals,” explains Gürtler. In order to accommodate the ever growing customer base quickly and flexibly, Big Dutchman decided to build a new logistics centre in 2008. “The previous premises were too small and could no longer cope with the demand,” recalls Gürtler. When the new building was commissioned, the company also began converting its fleet of forklift trucks from diesel to electric.

Today Big Dutchman is using 15 reach trucks, 35 front-loaders and nine narrow aisle forklift trucks from several manufacturers at the new logistics centre. A pool of 88 traction batteries ensures that the forklift trucks are always available - the company operates exclusively on a three-shift basis. However, managers were initially unsatisfied with the charging technology used for the energy storage units. “The devices supplied to us by the various manufacturers demonstrated a low level of efficiency and high energy loss,” explains Logistics Manager Gürtler. “The batteries were also extremely hot during charging. This had a negative effect on the service life and caused defects on a regular basis, much to the detriment of our warehouse operations.”

The reason behind this soon became clear: with conventional charging processes, such as 50 Hz transformer technology, the batteries are charged using a fixed characteristic with a predefined current. This leads to a considerable power loss, as the battery cannot completely absorb this high level of current. In addition, excessive overcharging occurs at the end of the charging cycle, which heats up and therefore damages the battery. “The higher the temperature, the greater the damage and the more quickly the service life is reduced,” summarises Gürtler.

Innovative charging process increases efficiency and service life

During the search for a more suitable solution, the logistics managers discovered the Fronius exhibition stand at the 2013 LogiMAT trade fair. The Austrian specialist in innovative battery charging systems had just presented its latest generation of Selectiva battery charging systems for electrically powered forklift trucks. These were equipped with a revolutionary innovation: the specially developed Ri charging process, which minimises energy loss during charging, thus lowering energy costs and CO2 emissions. Furthermore, the ultra cool charge this process provides increases the service life of the batteries. “A new technology that is not only more energy-efficient, but also offers gentler charging - that got my attention immediately,” recalls Gürtler, who promptly requested a test device from Fronius Sales. 

In mid-2013, Big Dutchman began to conduct its first trials with the Selectiva battery charging systems, which produced excellent results: “Our measurements showed that the Fronius devices enable much cooler charging and consume far less energy,” says Gürtler, clearly impressed. The secret to this improvement lies in the Ri charging process. Unlike conventional technologies, the charging process does not follow a standard characteristic. Instead the charging current is determined by the battery's effective inner resistance (Ri), which in turn is dependent on the age, temperature and state of charge of the battery. “Each charging cycle is therefore unique and has an individual characteristic,” explains Stefan Rasche, Technical Consultant for battery charging systems at Fronius. “Overcharging, which causes high energy losses and harmful battery warming, can thus be minimised.” For the operator, this system offers two significant advantages: it increases energy efficiency during charging, thereby reducing energy costs, and it extends the service life of the battery. Since the Selectiva devices also deliver the best results in direct comparison with other HF battery charging systems, Big Dutchman decided to work with Fronius.

Simple, flexible and user-friendly

In February 2014, the company commissioned the first charging station with 21 Selectiva 8120 devices. Around half of the 88 traction batteries in use at the Vechta logistics centre are charged here. Each device has an output of eight kilowatts and is suitable for batteries with a voltage of 12 to 80 V. “This makes things much simpler for our employees and prevents errors, as they don't have to think about which battery to connect to which battery charging system,” enthuses Gürtler on the flexibility enjoyed. An additional product feature also helps to reduce the workload for warehouse employees: a clearly visible LED strip on each battery charging system displays the status of the connected battery. “Orange indicates that charging is in progress, green indicates that the battery is fully charged and blue indicates that the battery has cooled down and is ready to use,” explains Stefan Rasche. A precise, real-time battery charging system display also shows which battery has been fully charged for the longest. “This improves the utilisation of the battery pool and in turn has a positive effect on service life,” emphasises Rasche.

The managers at Big Dutchman are extremely satisfied with the Fronius battery charging systems. “The performance and availability of all batteries - even old batteries - has improved dramatically,” reports Bernd Gürtler. “Faults and downtimes due to defective batteries have also become a much rarer occurrence.” At this stage it is still too early to identify the effects of the system conversion on the overall operating costs. However, Big Dutchman anticipates a considerably longer service life for traction batteries. “With procurement costs averaging around 4,000 euros per battery, this represents a huge potential saving,” says Gürtler. If the Fronius technology continues to prove itself so emphatically, it is only a matter of time before further purchases are made, reports the logistics manager. “The plan is to equip another charging station here in Vechta and our logistics centre in Kuala Lumpur with Fronius devices.” From there, Big Dutchman can provide services to its customers in south-east Asia - perhaps soon with the help of innovative battery charging technology from Austria.