Modular Home Manufacturer Reduces Costs by Right-Sizing Lithium-Ion Batteries Based on Forklift Energy Needs

Summary

A manufacturer of mobile homes and modular residences aimed to convert its forklift fleet to lithium-ion batteries to meet stringent safety standards and achieve lower total cost of ownership over the batteries' lifespan. The manufacturer initially planned to install large 80-volt, 35.7-53.5 kWh lithium-ion batteries in all its counterbalanced forklifts and reach trucks, regardless of application or total operating hours. EnerSys® conducted an energy study to compare the performance and costs of several NexSys® iON lithium-ion battery sizes, ranging from 25.7 kWh to 53.5 kWh. The study revealed that some forklifts would be equally productive and more energy-efficient at a lower cost if powered by NexSys® iON batteries with capacities sized for their actual usage. The company adopted a more customized approach to forklift lithium-ion batteries, anticipating savings of $1.5 million by selecting appropriately sized batteries instead of opting for a single, standard lithium-ion battery that would provide significant excess capacity.

Situation

The prefabricated housing industry has grown steadily in recent years, driven by increasing demand for affordable housing. In fact, one in nine new homes built in the US is a prefabricated home. A leading manufacturer of mobile homes and modular residences has built many of these new homes, and demand has helped the company expand from one region to over 350 retail centers nationwide. The modular home manufacturer distributes building materials to its manufacturing facilities from 50 supply centers across the country. Six days a week, over a single shift, a fleet of 250 forklifts continuously moves tons of lumber, machine components, siding, windows, doors, and all other materials needed to assemble the homes.

Challenge

The company decided to replace its diesel and liquid propane (LPG) forklifts with electric forklifts powered by lithium-ion batteries because they are safer to use around flammable materials like wood. Additionally, they are more environmentally friendly regarding carbon emissions and waste chemicals from internal combustion engine vehicles.

Based on the 'bigger is always better' mindset, the manufacturer planned to switch to 62.4 kWh lithium-ion batteries with a 10-year warranty for all its vehicles to ensure a long lifespan and lower lifetime costs. However, the vehicle fleet consisted of various forklift models, including reach trucks and 2.7, 3.6, and 4.5-ton counterbalanced forklifts. The forklifts had different applications throughout the facility, meaning actual energy consumption and total operating hours varied significantly. The new, oversized approach to batteries would provide much more energy capacity than many of the forklifts would need during a single shift, six days a week.

Mapping Energy Needs

To identify the ideal lithium-ion batteries that would optimize performance for the entire forklift fleet, EnerSys® assisted the modular home manufacturer in identifying the actual energy needs for all their forklifts by measuring average energy consumption (ampere-hours). This would help them optimize the fleet's energy consumption, making it more efficient and reducing costs.

To identify the actual energy needs, EnerSys® conducted an energy study using typical usage data for each forklift, provided by the operations manager at one of the distribution centers.

EnerSys® processed the energy study data using its proprietary modeling program, EnSite™, applying usage-specific operating parameters and energy requirements to assess the feasibility of battery solutions and generate reports comparing battery and charger sizes with costs.

Solution

Based on the unique energy needs of each individual truck, EnerSys® recommended various NexSys® iON battery capacities to meet specific energy requirements at the lowest possible cost. For example, the 3.6-ton forklifts were best suited for the 44.6 kWh NexSys® iON battery capacity for a single shift, which would make them 35% cheaper and require less energy to fully charge the batteries compared to the largest NexSys® iON battery at 62.39 kWh.

EnerSys® recommended an expected lifespan consistent with the equipment's expected service life. This avoided unnecessary costs associated with purchasing more expensive batteries that would last longer than the equipment they were intended to power.

Results

Over several years, the modular home manufacturer has replaced internal combustion engine lift trucks with trucks powered by NexSys® iON batteries, thereby reducing emissions and energy costs. All batteries come with a 7-year warranty.

By using NexSys® iON batteries sized for each individual forklift, the manufacturer will avoid overspending on the largest battery. This provides an estimated saving of over $1.5 million over the batteries' lifetime.

Energy Study Data Overview