Mounted above head height to leave more space in the hall

SPAR is the world’s largest voluntary concentration of grocers in a franchise system. Although the shops, wholesalers and supermarkets bear the same name and have a uniform logo, they are independent companies. The SPAR store fir tree emblem is now famous in 49 countries on four continents – including Switzerland. The retail chain has deep roots here – as far back as 1761, when the predecessor of the present-day SPAR Group established a “delicatessen” in St. Gallen, offering products such as coffee, tea, chocolate, spices, imported goods and other everyday items. In 1944, the thriving grocer’s shop added fruit and vegetables to its list, and also introduced fresh produce in 1967. When the franchise agreement was finally signed in 1989, it marked the foundation of the Swiss SPAR Group, which now acts as a holding company with three operating companies: SPAR Handels AG, TopCC AG and SPAR Management AG. The store network now includes 185 neighbourhood and convenience stores, as well as eleven TopCC cash-and-carries for caterers, business customers, clubs and public institutions.

These are supplied from the SPAR Group central warehouse, which is still located in St. Gallen. The ultra-modern logistics centre does not have much in common with the grocer’s shop of that time, of course: the 33,000 square metre storage area houses around 8,800 different items with a total value of approx. 26 million Swiss Francs. More than 600,000 roll cages leave these halls every day, transported by lorry to stores and partners across the land. An in-house fleet of 100 electric forklift trucks ensures the fast and efficient flow of goods. As SPAR operates a shift system, the forklift trucks and their batteries must be designed for long periods of use. The company does not use back-up batteries.

Until recently, SPAR mostly used 50 Hz devices to charge the traction batteries. These huge units occupied a great deal of space, which is why they were kept in a separate basement room. “It was a rather inconvenient solution, though,” remembers Daniel Stohr, the warehouse division manager. “The service lift had to take each forklift truck to the charging room individually for it to be connected up – an extremely time-consuming process for a fleet the size of ours. Because it was constantly in use, the operating and maintenance costs for the lift were quite considerable too.” 

SPAR therefore decided to modernise the charging infrastructure. The company came across the Austrian company Fronius at a logistics trade fair. Fronius develops customised complete systems for customers who need to charge traction batteries – always with the objective of saving energy and costs and optimising intralogistics processes. “The first thing we did was get together and closely scrutinise the actual situation at SPAR, so that we could then develop proposed solutions for improving daily working procedures,” explains Reto Baumgartner from the battery charging systems sales team at Fronius Switzerland. “We agreed these with the customer and then implemented them together.”

Space-saving and standards-compliant installation

The most important change was moving the battery charging technology from the basement to the ground floor, to the workspace of the forklift truck fleet. Fronius Selectiva battery chargers are ideal for this: they are far smaller and lighter than the 50 Hz devices previously used, allowing a flexible and space-saving approach to installation. Fronius set up a number of decentralised charging areas that are within easy reach for forklift operators. Chargers are attached to the wall, for example – or in one case, are even integrated above head height in the steelwork construction of a high-bay warehouse. A spring balancer ensures that the charging cables do not rest on the floor when not connected to a battery. “Of course, we made sure that all safety rules and standards were met for every variant,” notes Baumgartner.

SPAR employees also benefit from the chargers’ external start/stop function, which means that to charge the batteries, all they have to do is connect the cable – there are no settings that have to be made on the device itself. The Selectiva devices automatically detect the voltage, capacity and state of charge of the connected battery and adapt the charging characteristic accordingly. A pilot contact in the plug also prevents sparking if the charging cable is disconnected prematurely – “after all, highly-explosive oxyhydrogen can be released when charging lead batteries,” remarks Baumgartner. However, Fronius technology makes sure that warehouses are as safe as possible – as well as allowing simple and correct operation.

Gentle charging maintains battery capacity

The Ri charging process of the Selectiva devices is also a particularly gentle and efficient way to power traction batteries. The effective inner resistance (Ri) of the batteries – which depends on various factors such as their age, temperature and state of charge – is recorded, so that the level of charge for each battery is exactly what is required. This minimises harmful warming, maintains battery capacity and extends the service life. Charging times are now also far shorter than before. “This has noticeably improved the availability of our fleet,” explains Thomas Broder, head of logistics technology at SPAR. “The forklift trucks do not go to the charging station as often and are also ready for use again more quickly.”

Lower operating costs are another positive effect. Firstly, the new Selectiva devices reduce energy consumption for charging the forklift trucks by as much as 30%. Secondly, Fronius and SPAR were able to extend the service life of the traction batteries by around one third – meaning that the expensive batteries had to be replaced less often. Water consumption also fell thanks to the gentle charging process, which in turn reduces maintenance expenditure. “The new charging infrastructure has allowed us to make considerable savings,” says a satisfied warehouse manager Daniel Stohr. “Not only that, we have gained valuable space.”

Expert advice, right from the start

A total of 35 Selectiva battery chargers are now in use in SPAR’s central warehouse, where managers are completely satisfied with the result – as they are with the collaboration with Fronius. “Right from the start, we were given expert, constructive and results-oriented advice,” praises Stohr. “A particularly positive aspect for us was having our own designated contact person, from planning, to implementation, to operation – this made the conversion far easier for us.” The warehouse manager also wanted to point out that Fronius looked into the specific situation at SPAR before developing a customised solution. “I am convinced that after working so successfully with Fronius on this, they will be our first choice for future projects as well.”