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Strengthening Warfighter Readiness and Lethality DLA Carries a Heavy Load

Where batteries are concerned, capacity equals time. Greater energy storage capacity translates into more operational time for the equipment that batteries power and less downtime related to charging or replacement. Developed in the 1970s, a lithium-ion battery is a type of rechargeable battery with a high-energy density, tiny memory effect, and low self-discharge. They are one of the most popular types of rechargeable batteries for portable electronics and have become common in computers, cell phones, power tools, and tablets. Now, lithium-ion batteries are the preferred method of powering electric cars, backup power supplies, solar panels, and even wheelchairs.

The DLA took notice of lithium-ion battery technology’s ubiquity and operational advantages, and for good reason. DLA’s worldwide network of distribution centers employs 2,397 battery-operated forklifts to send and receive over two thousand tons of goods every day. In the Susquehanna, PA facility (DDSP), there are over ten million square feet of storage space, and forklifts travel over distances equivalent to the length of 30 football fields each day. The current fleet of forklifts is being powered by lead-acid batteries, a technology that has been around for more than 100 years. Each battery weighs over 2,200 pounds and requires eight hours of charging and eight hours of cooling before it can be used. With distribution centers spread across the globe, employing about 7,000 workers who manage and move $105 billion in inventory, utilizing agiler and consistently powerful forklifts could be a huge advantage.

Real world testing

Operational forklifts are critical to operational readiness, but are the lithium-ion-battery-powered forklifts really the right solution for the job?

“The primary shortcomings of lead-acid batteries that we are trying to overcome include short battery lifecycles, huge battery inventories (for multi-shift operations), the size and expense of dedicated battery rooms, and the labor investment for battery exchanges and maintenance,” says Eugene Summers, a strategic planner in the DLA Distribution J5 Office of Future Plans.

Working through the CTMA Cooperative Agreement contract vehicle, DLA is partnering with Navitas Systems, an energy storage and power electronics company, using their Starlifter heavy-duty lithium forklift battery system.

The test program formally began in November 2016. At DDSP, six Crown 36-volt forklifts powered by lead-acid batteries are being tested against six Crown 36-volt lithium-ion battery-powered forklifts in multi-shift operations. The DLA also recently began testing lithium-ion batteries in their distribution center in San Joaquin, CA (DDJC). In DDJC’s cold storage facility, five Hyster 48-volt lithium-ion battery- powered forklifts are going against five propane-powered forklifts in a multi-shift operations environment.

At DDJC, DLA would like to eliminate carbon monoxide emissions that can cause health and safety issues with the operators. Lithium-ion batteries will not only eliminate those emissions and meet California workplace standards but will also reduce the noise produced from the propane-powered lifts. Elimination of propane will also increase operational time and reduce wear and tear on the forklifts, as they will no longer have to travel outside the warehouses to their refueling stations.

Benefits to using lithium-ion batteries include:

  • Never having to remove the batteries from the forklift.
  • Charging time of about one hour for eight hours of performance.
  • Sealed battery packs, eliminating any odor and the hazardous task of refilling acid battery cells.
  • Fewer batteries needed in inventory.

A Joint Test Protocol (JTP) was approved outlining data and metrics that were to be collected and aggregated. These metrics included information gathered from monitoring equipment, maintenance activities, battery exchanges, and driver surveys. The collected data has been documented and an operational profile of the batteries has been created.

“Across both trials, we have data collection devices in place to record forklift usage times, state of charge over time, voltage, amp hour usage, charging times, and energy consumption. Additionally, we are gathering qualitative assessments from forklift operators on their perceived performances and shortcomings of each energy solution over the course of the trials,” says Summers.

With a hint of fun, the DLA and Navitas Systems are calling the testing the Heavy Lifter Forklift Challenge. “During the testing, we are constantly fine-tuning the lithium battery systems to be more efficient. There is a lot on the line here,” says Mil Ovan, President and Chief Marketing Officer of Navitas Systems.

The results are coming in

Since the testing is still underway, it is too early to draw conclusions. However, anecdotally, the operators seem to prefer operating the lithium-ion battery forklifts.

“We are seeing a consensus in operator feedback that eliminating the need for exchanging batteries both increases their operational availability and reduces a perceived safety risk in lead-acid exchange. A limitation of our test is the location of the lithium opportunity chargers. If we were in full-scale implementation, we would locate them in common forklift parking areas and near break rooms. Those with a lithium charger currently installed near their workstations find the quick charging to be beneficial to their operations. Those that don’t have an opportunity charger near the typical operations area don’t like traveling out of their way for charging. This supports the understanding that wide-scale implementation of the lithium batteries would require detailed planning to install chargers at the most beneficial locations,” says Summers.

The testing and evaluations will finish this summer. Any change to the forklift program will likely happen incrementally after the completion and review of a full performance analysis, business case analysis, and final report.

If lithium-ion batteries perform as advertised, the Services will want to consider adoption. For example, Ovan sees lithium-ion battery-powered forklifts as a perfect fit for Navy ships where propane forklifts vent exhaust in enclosed spaces.

The results that this CTMA project gets from the lithium-ion battery project with DLA could easily transition throughout the DoD, realizing tremendous benefits from lower costs, less maintenance, increased operational time, and a more productive workforce.