Modular Home Manufacturer Reduces Costs by Correctly Sizing Lithium-Ion Batteries for Each Forklift's Energy Needs

Summary

A manufacturer of modular and mobile homes sought to convert its forklift fleet to lithium-ion batteries, meeting strict safety standards and reducing total battery lifespan costs. The manufacturer initially planned to install large 35.7 to 53.5 kWh, 80-volt lithium-ion batteries in all its sit-down and reach trucks, regardless of application or total operating hours. EnerSys® conducted a power study to compare the performance and costs of several NexSys® iON lithium-ion batteries in various sizes, ranging from 25.7 kWh to 53.5 kWh. The study revealed that some forklifts could be just as productive and more energy-efficient if powered by appropriately sized NexSys® iON batteries at a lower cost. The company adopted a more customized approach to its lithium-ion batteries for forklifts and will save $1.5 million by correctly sizing its batteries instead of standardizing on a single, oversized lithium-ion battery.

Situation

As people seek more affordable housing, the prefabricated housing industry has seen consistent growth. In fact, one in nine new homes built in the United States is prefabricated. One of the leading manufacturers of mobile and modular homes has built a large number of these new homes, and demand has allowed the company to expand from a single site to over 350 retail locations nationwide. The modular home manufacturer distributes construction supplies to its manufacturing sites from 50 supply centers. Operating on a six-day work week, a fleet of 250 forklifts continuously moves tons of wood, hardware, siding, windows, doors, and all other materials needed to build complete homes.

The Challenge

The company decided to switch its previously diesel and propane-powered forklifts to electric equipment powered by lithium-ion batteries, as they are safer to use around highly flammable materials like wood and are more environmentally sustainable in terms of carbon emissions and chemical waste from combustion-powered equipment. Assuming that bigger is better, the manufacturer planned to switch to 62.4 kWh lithium-ion batteries with a 10-year warranty to ensure a long lifespan and reduced costs throughout the battery lifecycle. However, the fleet consisted of different forklift models, ranging from reach trucks to 2,700, 3,600, and 4,500 kg counterbalanced trucks. The forklifts were used for different applications across the site, so their actual electricity consumption and total operating time varied considerably. Their approach of using oversized batteries would have provided significantly more energy capacity than most of their forklifts needed during a single, six-day work week.

Defining Energy Needs

To find the ideal lithium-ion batteries that would optimize the performance of its entire forklift fleet, EnerSys® helped the modular home manufacturer identify the real energy needs of all its forklifts by measuring average consumption (in amp-hours). This would optimize the fleet's energy usage in terms of efficiency and cost. To determine the real energy needs, EnerSys® conducted a power study using typical usage data for each forklift provided by a distribution center’s operations manager. EnerSys® processed the power study data with its proprietary EnSite™ modeling software, applying application-specific operating parameters and energy requirements to evaluate the feasibility of battery solutions and generate reports comparing battery and charger sizing and costs.

Solution

Based on the specific energy needs of each forklift, EnerSys® recommended several NexSys® iON battery capacities for each forklift to meet specific energy needs at the lowest cost. For example, the 3,600 kg forklifts were better suited to the power of the 44.6 kWh NexSys® iON battery for one of its single-shift operations, which is 35% less expensive and requires less energy to recharge completely than the larger 62.39 kWh NexSys® iON battery. Furthermore, EnerSys® recommended a lifespan that matched their equipment’s expected lifespan, allowing them to avoid unnecessary costs associated with purchasing more expensive batteries that would have lasted longer than the equipment they powered.

Results

For several years, the modular home manufacturer has been transitioning to the correct size NexSys® iON batteries for its combustion forklifts, reducing emissions and energy costs. All batteries are covered by a 7-year warranty. By using custom NexSys® iON batteries for each forklift application, the manufacturer will avoid overspending on larger batteries, with an expected savings of more than $1.5 million over the batteries’ lifespan.

Power Study Data Overview