Electrification of the forklift fleet has become a priority for many material handling operations that are catching up with this industry trend. In 2018, more than half of all forklifts sold in the United States were electric, and the transition to electric power has only accelerated in the past few years.
The shift from liquefied petroleum gas (LPG) to electric forklift is bringing tangible and proven benefits to all forklift operations, including lower operating and total cost of ownership, and safer, cleaner and quieter workplace conditions. The forklift lithium battery technology makes this conversion feasible in many heavy duty applications. In this article, we show how to correctly calculate the ampere hour (Ah) capacity of lithium battery of forklift truck, so as to change the former to electric forklift truck.
Advantages of lithium forklift truck in response to high operating conditions
Today, diesel forklifts are still used by many companies, partly because of business inertia, and partly because the old generation of electric forklifts is not easy to replace. Low capacity lead-acid forklift batteries have inherent limitations and cannot support efficient operations, such as paper, packaging, wood and metal industries, especially under extremely low or high temperatures and outdoor working conditions. Long distance driving, driving on the ramp, heavy objects, high lifting, and the use of forklift accessories, such as paper clips, all bring additional pressure to the power supply.
Lithium battery eliminates these obstacles, and its benefit is to reduce operating costs and pollution. In a battery pack of the same size, lithium batteries can store much more energy than lead-acid batteries, and can be quickly recharged during breaks and lunches to continuously complete the daily multi shift work.
Comparison between LPG forklift truck and lithium electric forklift truck
In general, LPG forklift is equivalent to diesel and gasoline powered forklift. LPG engines produce low levels of noise and air pollution in the workplace, and their refueling costs are lower than those of other diesel or natural gas engines.
However, the operation and maintenance costs of LPG forklift trucks are much higher than those of electric powered forklift trucks. Therefore, it is only a matter of time before almost all internal combustion forklifts will transition to electric forklifts. In fact, in some American states, the time has been set. For example, California will not allow the sale of new internal combustion forklifts unless they are zero emission forklifts from 2026.
Among today's commercial advanced power sources, lithium battery solutions have the highest return on investment. The development of lithium iron phosphate (LFP) battery in the material handling industry was carried out after the large-scale use of these batteries in electric buses and electric passenger vehicles (EVs). When it was introduced into the material handling equipment, this technology has been proved to be quite mature.
In addition to safety and environmental benefits, lithium batteries provide users with significant improvements in forklift performance: faster driving and lifting speeds, less downtime, and no acid spillage or smoke. But what really makes it possible to use lithium battery technology is the proven return on investment of forklift lithium battery, which is accompanied by significant savings in energy, labor and infrastructure costs.
Total cost of ownership
Now you can see a real example. Let's calculate the total cost of ownership of LPG and lithium powered forklift trucks. These calculations are based on 5 electric and 5 LPG forklifts of the same brand, which operate 5 days a week, 3 shifts a day, and last for 5 years. Lithium batteries have a cycle life of up to 10 years, depending on application and usage. This value cannot be ignored. To simplify the analysis, we did not consider the residual value of the forklift and battery.
The equipment cost of electric forklift is high in the early stage, but the savings within five years are very considerable. Using lithium powered forklift, the company saved labor and maintenance costs. The rule of thumb is that the maintenance cost of electric forklift is one third of that of diesel forklift.
However, the real difference lies in the comparison of power cost and LPG fuel cost. The company eventually paid 10 times less for electricity than for propane. The price of electricity and LPG varies from state to state, but the difference is huge. In this case, the total cost saved by using lithium battery forklift compared with diesel forklift is about 56% of the latter, that is, 400000 dollars.
Table 1. Calculation of total cost of ownership: LPG and lithium electric forklift.
Calculate battery ampere hour (Ah) capacity
In the above example, we juxtaposed similar forklift models of the same brand driven by LPG and lithium battery. In order to run this analysis correctly, we need to compare apples with apples, that is, engines need to be similar in terms of energy and power output. The following is how OneCharge engineers calculate the lithium battery parameters for the transition from LPG to electric forklift.
LPG and lithium battery.
We usually advise our customers to choose a higher voltage battery option so that "there is more gas in the tank", in order to prepare for unexpected additional running time or missed charging events. In addition, it is a good practice to keep the battery charging state above 50% to extend its cycle life, so additional Ah capacity is always helpful.
Due to inertia, long-term business relationship with local material handling equipment dealers and lack of understanding of lithium battery technology, many companies still insist on using old LPG forklifts today. Typically, you will find LPG forklifts in outdoor operations in the wood, paper and recycling industries. Traditional commercial and financing terms for leasing material handling equipment may also prevent customers from transitioning to electric forklifts. For example, if the contract of the third-party logistics company is three years, then by the end of the lease period, the utilization rate of the high price electric forklift is still far from 100%, and the market has not yet provided a standard way to recover the high residual value of lithium batteries after only three years of use.
There is no doubt that these problems will be solved in the near future. Although less efficient technology is hard to get from (remember your VHS cassette recorder?) However, the current consensus on the urgency of fossil fuel energy transformation, combined with economic benefits, will promote many industries to accelerate the use of lithium battery powered electrical equipment.
We are beginning to see the use of lithium batteries in heavy machinery other than material handling equipment. Successful commercial projects include electric cranes and excavators in the construction industry, and locomotive engines in trains. The sea transportation experiment is under way, followed by aviation, and there is no doubt that its power equipment will be electrically driven.
