Cold temperatures deplete the amount of usable energy from batteries operating the trucks, reports Jimenz at Toyota. “It has been documented that the battery’s capacity in a cold-store environment could be as low as 65 percent of that available at normal ambient temperatures. So in a typical 1000-amp battery, you really have only about 650 amps of energy available. This dramatically reduces run time, leading to lower levels of productivity and requiring either the use of a fast-charge system or more frequent battery changes to get through the work day.”
Recognizing this, Toyota improved the efficiencies of its controllers, drive motors, and lift motors so the energy required by these components lessen their impact on the truck’s energy requirements overall. “We use AC motors and controllers which utilize fewer moving parts, resulting in reduced component heat buildup and improved energy efficiencies,” explains Jimenz. Last year the company introduced its latest-generation four-wheel electric featuring Toyota’s most energy-efficient AC-powered system to date.
The choice of greases and oils is critical to the performance of your trucks, notes Micheletto. “Confirm what type of oil and grease your application requires and understand what their temperature ranges are before their viscosity thickens or thins. Remember that the most expensive oil is often the cheapest in the long run simply because it will do the best job.”
Switches and other electronic devices are also at risk when exposed to cold temperatures. “They can condense on the inside and to prevent that from happening, we introduce various forms of heat to evaporate the moisture,” Micheletto says. “It’s not that it’s bad for them to get wet. The problem arises when you go back into a freezer where switches can freeze closed. By keeping the switches heated, we minimize the risk of any issues developing, extending the life of the switch so the truck will run longer.” This is done using resistance heating, indirect heating to a specific area, or truck-generated heat that is channeled to the required components.
Choosing the right tires for your application is also critical, as freezer and cooler areas are ripe for traction problems. “Many electric lift trucks in these environments are equipped with polyurethane tires rather than rubber tires,” reports Bowles at Mitsubishi Caterpillar. “It’s important to consider a poly-traction tire that is siped, treaded, or even sanded. For instance, we offer a 4,500-pound walkie—popular in the produce industry—that uses an optional rubber or sanded poly drive tire for those cold and wet conditions. A lack of traction can accelerate tire wear and this becomes a maintenance cost over the life of the truck.”
There’s no doubt about it—these environments can become very slippery as trucks sweat, increasing the potential for tip-overs. Toyota offers its System of Active Stability on its sit-down counter-balanced trucks to compensate for these situations. “When the system senses instability, it engages a swing lock cylinder to stabilize the rear axle to help keep all four tires on the ground.”
Driver comfort and safety is high on the list of priorities in choosing the right truck. Because operators must work with heavy and bulky freezer suits, manufacturers are sensitive to providing a user-friendly work area. “We design our equipment so operators are as comfortable as possible when they are working,” says Susan Comfort, product manager, narrow aisle products at The Raymond Corp. in Greene, NY. “Handles and floor mats are heated for their comfort.”
Yale provides the maximum amount of adjustability in its steer tillers, reports Micheletto. “Operators can easily change the position of the steering wheel so that it doesn’t rub against their bodies as they work. Our function controls—such as the handles—are ergonomically designed and engineered so operators can control them even when they are wearing heavy mittens or gloves.”
Maintenance For Performance, Safety
It’s critical to conduct periodic inspections on equipment used in these harsh environments and most manufacturers suggest that end users conduct inspections every 250 hours to 500 hours. “We at Raymond recommend that you adhere to the OEM’s suggested scheduled maintenance,” says Comfort. “Make sure everything is properly greased. Housekeeping is also very important to consider in keeping maintenance costs under control. For instance, pick up loose pallet debris so it doesn’t damage tires, which can lead to premature tire damage.”