Battery charging division on board
19 March 2014
Gebrüder Weiss has reviewed its procurement procedure and the total cost of ownership for forklift trucks and associated energy packages by considering vehicles, batteries and battery charging systems separately. As a result, the logistics specialist chose to bring the Battery Charging Systems division of Fronius International on board.
It goes without saying that a logistics service provider the size of Gebrüder Weiss operates a large number of distribution centres for land, air and sea transport in which a sizeable fleet of forklift trucks is at work. For example, around 1100 – mainly electrically powered – machines are used by the company's 80 subsidiaries. Around half of these are low-lift pallet trucks, about 20% are counterbalance trucks, and warehouse technology, such as high bay or narrow-aisle stackers, accounts for close to 30%.
"The forklift trucks at Gebrüder Weiss need to be able to withstand demanding and varied conditions,” explains Lukas Strobl of Central Purchasing. "At some sites the vehicles are in use more or less continually, that is up to 20h/day, seven days a week. At peak periods in particular the flow of goods must be handled quickly and efficiently. For us, knowing we can rely on our equipment is of key importance. Any breakdowns would be costly and time-consuming.”
With so many electric forklift trucks, traction batteries and battery charging systems, it was worth taking a closer look at the total cost of ownership for new or replacement equipment. Even though the traction battery and battery charging system - known as the 'energy package' - are only equivalent to 10 to 25% of the total procurement costs, both components have a significant impact on operating costs. This is largely due to increasing energy costs and the high cost of the battery. The energy package affects the dimensioning of the technical infrastructure for new warehouses or logistics centres, such as mains connections, power factor correction measures, space requirements or ventilation systems where batteries are charged.
The forklift provider is frequently the only contact for the purchasing company, since the user often views the forklift truck, traction battery and battery charging system as a single, indivisible entity. This was certainly the case at Gebrüder Weiss. However, the company decided to consider the forklift truck, traction battery and battery charging system as separate elements. Lukas Strobl explains: "Doing business sustainably is part of our quality undertaking. For us intelligent logistics starts with the analysis of the procurement process as a whole, including the procurement of battery charging systems. If the different processes are aligned, everything runs like clockwork and effective use can be made of synergies. This not only helps to save energy, but also reduces CO2 emissions.”
In the procurement process for the three separate components, Gebrüder Weiss evaluated all suppliers on the basis of various criteria, such as quality, sales structure and cost. Lukas Strobl felt that Fronius stood out from the competition and decided to enter into a partnership with the Austrian specialist for the supply of battery charging systems and signed a cooperation agreement to this effect. Lukas Strobl adds: "We view our suppliers as partners and seek to work together on an ongoing basis. In other words, business processes, for example changing vehicle batteries, are evaluated jointly and adjusted if appropriate. Both companies benefit from this continuous development.”
The new Selectiva generation of battery charging systems for intralogistics from Fronius is based on the 'Active Inverter Technology'. The key feature of this is the Ri charging process with its individual characteristic. Ri stands for the effective inner resistance of the battery: a battery-specific value that changes during charging and discharging due to the fluctuating acid concentrations and other effects. What makes the Ri characteristic different is that, by measuring the effective inner resistance, the charging voltage rather than the charging current is specified. This ensures that the charging current is automatically adjusted to remain in line with the effective inner resistance curve of the battery. In each phase of the charging process, the battery only receives the current that it can actually absorb, ensuring that overcharging does not take place.
According to Fronius, the individual Ri charging characteristic means that the newly developed Selectiva devices achieve maximum energy efficiency, reduced CO2 emissions and improved service life for costly traction batteries.