The DoD Defense Logistics Agency (DLA) owns and operates large fleets of Class 1 & 2 forklift trucks for material handling purposes. Within DLA Distribution, 2,397 of these forklift trucks are electrically powered by very large lead batteries. While sufficient for low to medium-intensity warehouse applications, these batteries face performance challenges for high-intensity, multi-shift warehouses and/or cold-temperature warehouse applications.
Challenges have been historically overcome by the daily utilization of multiple batteries in rotation per truck, creation of dedicated battery rooms for service and maintenance, and significant investment in labor to care and service the lead batteries as well as the associated lead battery change equipment. Lead batteries also take several hours to recharge, and extensive man-hours to rotate with a charged battery.
Newer “zero maintenance” long-life batteries based on energy storage chemistries such as lithium are now becoming available, which are more suited for high-intensity warehouse duty cycles and cold-temperature warehouse applications. These batteries can also be rapidly charged during traditional 15-minute breaks or 30-minute lunch breaks, alleviating the need for battery change-outs and associated driver down-time during the day.
Beginning in September of 2016 partnering with Navitas Systems and now partnered with the energy storage company East Penn Manufacturing, DLA began exploring the use of lithium-ion batteries for forklifts through CTMA projects specifically at DLA Distribution Susquehanna, Pennsylvania (DDSP) and San Joaquin, California (DDJC) warehouse depots. DDSP tested the 36-volt lithium-ion batteries in some of their electric/lead-acid battery forklifts, and DDJC tested the 48-volt lithium-ion batteries in electric forklifts replacing their gas engine/propane forklifts.
By the conclusion of the project there was no doubt about the outcome. The equipment managers were thrilled with the batteries because of the shortened charging times of lithium-ion versus the lead batteries, as well as the consistent strong lifting performance throughout the shift. Instead of keeping three batteries per vehicle for three-shift operations, the lithium-ion batteries could be charged at breaks or between shifts.
“The two DLA depots were the first in the world to try these 36 and 48-volt lithium-ion batteries, and the subsequent Return on Investment analysis shows a great payback,” says Mil Ovan, Chief Marketing Officer, Navitas Systems. “There’s no single battery solution that serves all needs. Lithium-ion batteries will not make the lead batteries obsolete, but they are a terrific fit in certain applications, especially in a two or three-shift high-tempo environment.”
Results from the project will serve as valuable information for DLA when replacing or planning for future procurement of batteries for their forklifts throughout their networks moving forward. “The CTMA Program helps government agencies save time in sorting through the myriad technology alternatives available, and set-up comprehensive trials to assess the most promising sub-set. We are delighted to have worked with DLA and Navitas Systems, and to see the positive impact these two trials had on material handling productivity. Now other government agencies can determine how lithium plays into their own plans with confidence, knowing that the battery was put through all of the paces successfully,” says Debbie Lilu, CTMA Program Director.