DC Velocity - May 2015

with that simple visual system, compliance was spotty, he says.

This method produced limited improvement, so DSC asked its battery supplier for ideas. EnerSys suggested an automated battery management system that could address all of its customer’s concerns.

SURPRISE TEST RESULTS

The automated battery management system installed by EnerSys, called EZ Select, ensures that all batteries are evenly rotated. “The system monitors the chargers, and when a charge is complete, that battery goes into a queue organized by cool-down time,” explains Paul Roeser, national accounts manager for EnerSys.

At DSC’s University Park facility, when an operator enters the battery changing area, he or she uses an automatic bat-tery-change cart to insert the depleted battery into an empty slot before hooking the battery up to a charger. Next, the operator looks at EZ Select’s light-emitting diode (LED) display panel, which is mounted on a pole at one end of the battery charging area. The display panel indicates the number of the charger position where the next available properly charged (and longest-cooled) battery is located, Roeser explains. The operator uses the cart to extract the fresh battery, rolls it back to the lift truck, and installs it in the vehicle.

If an operator attempts to take a battery other than the one indicated on the screen, an alarm immediately sounds. The battery management system also applies a date and time stamp to the error, a feature that identifies which operators are making the mistakes. That allows DSC to coach employees who need more training, an approach that quickly paid off. “Now, the employees get it: If we all follow this, then we’ll all get good batteries,” Chamberlain has a fleet of 45 forklifts, including

22 standup counterbalanced trucks, 11 standup deep-reach trucks, one order picker, and four pallet jacks, all manufactured by Crown Equipment Corp. (The balance are short-term rental trucks.) The fleet is powered by a pool of 85 batteries, all of them purchased from EnerSys, including a single model for all of the standup counterbalanced and deep-reach trucks. That degree of standardization pays off by simplifying vehicle maintenance and opera-tor/technician training; it also helps to keep purchase prices reasonable, says Jim Chamberlain, DSC’s senior director of industrial engineering and continual improvement.

While reviewing reports in DSC’s labor management system (LMS) some years ago, Chamberlain and his colleagues noticed that lift truck operators frequently made more than one battery change per shift.

Short battery run times were compromising productivity, but that wasn’t the only problem. There also appeared to be a correlation between the frequent changes and the batteries’ shorter-than-expected lifespans.

Observation revealed that improper battery selection was to blame, so the operations and industrial engineering teams came up with a “first in, first out” process to help drivers choose batteries that had been charged and fully cooled. In the battery changing area, there would be one empty storage slot; drivers were told to always put their used battery in that slot and take the fresh one immediately to the right.

“In theory, if everyone [follows the procedure], drivers will never get back to the battery they just put in until they have come all the way around [the storage slots],” Chamberlain explains. But even