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Introduction

In modern logistics and industrial production, forklifts, as important material handling equipment, have a crucial power source. Lead-acid batteries have been widely used in the forklift field due to their advantages such as low cost, mature technology and good high-rate discharge performance. Due to different operational requirements, the parameters of lead-acid batteries that different models of forklifts are compatible with also vary. A thorough understanding of these parameters is of great significance for forklift users to make reasonable selections, use forklifts efficiently and reduce operating costs.

Lead-acid battery type

Type

Flooded lead-acid battery: Also known as open-type battery, its electrolyte exists in a liquid state, and the battery cell has an openable liquid filling hole. This type of battery has a relatively low cost and can adapt to high current discharge. It is widely used in forklift operation scenarios where there are certain conditions for battery maintenance and cost is a concern. However, it is necessary to regularly check and add distilled water to maintain the electrolyte level and prevent the plates from drying out and affecting the service life.

Sealed lead-acid batteries: including AGM (adsorption glass fiber mat) and GEL (gel) batteries. AGM batteries use glass fiber MATS to adsorb the electrolyte. The electrolyte does not flow, which can effectively avoid leakage problems. They can work at different installation positions, have low internal resistance, and good high-current discharge performance. GEL batteries, on the other hand, transform the electrolyte into a colloidal state. They also feature sealing and maintenance-free properties, and have better tolerance to vibration and high-temperature environments. Sealed lead-acid batteries are suitable for forklift application scenarios with low maintenance requirements and relatively complex working environments.

Key Parameters and influences of lead-acid Batteries for Forklifts

Rated voltage

Common voltage levels: The common rated voltages of forklift lead-acid batteries include 24V, 36V, 48V, 80V, etc. Generally, small electric forklifts mostly use 24V or 36V batteries, such as electric pallet trucks with a capacity of less than 1 ton. These forklifts have a relatively simple structure and a lower working intensity. A lower voltage is sufficient to meet their power requirements. Medium and large forklifts with a capacity of 3 tons or more typically use batteries with a voltage of 48V or higher. For instance, common 3-ton counterbalanced forklifts often employ 48V or 80V batteries. Higher voltage can provide stronger power, enabling the forklift to handle heavier goods and adapt to more complex working conditions.

The influence of voltage on forklift performance: Voltage directly affects the power output of forklifts. The higher the voltage, the greater the rotational speed and torque of the motor, and the traveling speed, lifting speed and climbing ability of the forklift will all increase accordingly. However, the increase in voltage also poses higher requirements for the electrical system and insulation performance of forklifts, and accordingly, the manufacturing cost and maintenance difficulty will also increase.

Rated capacity

Capacity representation method: Rated capacity is usually expressed in ampere-hours (Ah), which refers to the amount of electricity that a battery can output under specified discharge conditions. The capacity range of common lead-acid batteries for forklifts varies from 100Ah to 1500Ah.

The relationship between capacity and range as well as operation time: Capacity determines the range and continuous operation time of a forklift after a single charge. Under the same working conditions, the larger the battery capacity, the longer the forklift can operate. Take a 2-ton electric forklift as an example. When using a 400Ah battery, it can operate continuously for about 4 to 5 hours within an 8-hour working day. If it is replaced with a 600Ah battery, the continuous operation time can be extended to 6 to 7 hours, reducing the frequency of charging and improving work efficiency. However, large-capacity batteries are often larger in size and weight, which will increase the weight of the forklift itself, affect the flexibility of the forklift, and at the same time, the cost is also higher.

External dimensions

Diversity in size specifications: The external dimensions of forklift lead-acid batteries vary significantly due to different models and capacities. For example, for a 24V, 250Ah lead-acid battery, its dimensions may be 965mm in length, 198mm in width and 480mm in height. The battery size of 80V and 500Ah May reach 1030mm in length, 700mm in width and 792mm in height. The size design needs to be perfectly compatible with the battery compartment of the forklift. The battery compartment sizes of different brands and models of forklifts vary, so the battery size specifications are diverse.

Impact on forklift layout and usage: The appropriate battery shape and size ensure smooth installation in the forklift battery compartment without affecting the layout of other forklift components. If the battery size is too large, it cannot be installed. If the size is too small, it will not be firmly fixed in the battery compartment. During driving, it may shake, affecting the performance and service life of the battery. In addition, the battery size also affects the overall center of gravity distribution of the forklift. A reasonable size design helps ensure the stability of the forklift during operation.

Discharge rate

Definition and Common discharge rates: The discharge rate refers to the rate at which a battery discharges, and is commonly expressed as "time rate" and "rate". The time rate, such as the 5-hour rate (5HR), indicates that the battery is completely discharged within 5 hours at a certain current.

The impact of discharge rate on battery capacity and lifespan: The higher the discharge rate, the lower the actual capacity that the battery can discharge. This is because at a high discharge rate, the chemical reaction rate inside the battery accelerates, and the polarization phenomenon intensifies, resulting in some active substances being unable to fully participate in the reaction. Long-term use with a high discharge rate will also accelerate the sulfation of the battery plates and shorten the battery life. Therefore, in actual operation of forklifts, it is necessary to avoid long-term high discharge rate conditions as much as possible to protect the performance and lifespan of the battery.

Cycle life

The meaning of cycle life: Cycle life refers to the number of cycles a battery can undergo charge and discharge under certain conditions until its capacity drops to the specified value. The cycle life of lead-acid batteries for forklifts varies among different types and qualities.

Factors affecting cycle life and its relationship with usage cost: The depth of charge and discharge of the battery, charging method, and the ambient temperature of use will all affect cycle life. Frequent deep discharges can significantly shorten the battery's cycle life, while shallow charging and discharging can help extend its lifespan. Reasonable charging methods, such as using smart chargers to avoid overcharging and undercharging, can increase the cycle life. Excessively high or low ambient temperatures can also have a negative impact on the cycle life. High temperatures can accelerate the chemical reactions inside the battery, leading to problems such as plate corrosion and water loss. Low temperatures will increase the internal resistance of batteries and reduce their capacity.

A comparison of lead-acid battery parameters suitable for different forklift models

1 ton electric pallet truck

Compatible battery parameters: Commonly compatible with 24V lead-acid batteries, with capacities mostly ranging from 150Ah to 250Ah. For instance, a 1-ton electric pallet truck of a certain brand is equipped with a 24V, 200Ah lead-acid battery, with dimensions of 624mm in length, 212mm in width and 627mm in height. This battery adopts a liquid-rich design, which has a relatively low cost and can meet the needs of such forklifts for short-distance cargo transportation on flat ground such as indoor warehouses.

Performance in operation: Under normal working conditions, it can operate continuously for 3 to 4 hours after being fully charged, which can meet the daily handling operation requirements of a general warehouse for 2 to 3 times. If sealed lead-acid batteries are used, although the cost is slightly higher, it can reduce maintenance work and is more suitable for working environments with strict requirements for battery maintenance.

2-ton counterbalanced forklift

Compatible battery parameters: 48V batteries are mostly used, with a capacity range of 300Ah to 600Ah. For instance, a 2-ton counterbalanced forklift is equipped with a 48V, 400Ah lead-acid battery, which measures 1000mm in length, 335mm in width and 755mm in height. This battery can be liquid-rich type, and some of them adopt AGM sealed type.

Operational performance: Taking a 400Ah battery as an example, when fully loaded, the forklift can travel at a speed of 12-15km /h, with a lifting speed of approximately 0.2-0.3m /s. A single charge can meet the continuous operation requirements for 5-6 hours. Compared with 1-ton forklifts, 2-ton forklifts have higher requirements for battery capacity and discharge performance due to greater operation intensity. The application of AGM sealed batteries in such forklifts can reduce the risk of electrolyte leakage, adapt to more complex working environments, and have good high-current discharge performance, which can enhance the forklift's ability to accelerate instantaneously and lift heavy loads.

Large forklifts of 3 tons and above

Compatible battery parameters: Generally, batteries with a voltage of 48V or above are used, with 80V being more common. The capacity ranges from 500Ah to 1500Ah. For instance, a certain 3-ton large forklift is equipped with an 80V, 500Ah lead-acid battery, and the iron box specifications are 1030mm in length, 700mm in width, and 792mm in height. This type of battery is mostly liquid-rich to meet the demand for high power output.

Operational performance: Large forklifts are mainly used for heavy-load, long-distance handling and frequent lifting operations. The 80V high voltage can provide strong power, and the 500Ah large capacity ensures a long range. Under heavy-load conditions, the forklift can reach a lifting height of 6 to 8 meters when fully loaded, with a traveling speed of 18 to 20 kilometers per hour. It can operate continuously for 7 to 8 hours on a single charge, significantly enhancing the operational efficiency of large logistics centers, ports and other places. However, due to the large battery capacity and high voltage, the requirements for charging equipment and battery maintenance are also more stringent.

Suggestions for Parameter Selection of Lead-acid Batteries in Forklifts

According to the working conditions of the forklift

Work intensity: For forklifts with low work intensity, short daily working hours, and the ability to handle light goods, such as electric pallet trucks that occasionally handle light loads in small warehouses, batteries with lower voltage and capacity, such as 24V, 150Ah - 200Ah batteries, can be selected. This not only meets the requirements but also reduces costs. Forklifts with high operation intensity, long continuous working hours, and frequent handling of heavy goods, such as counterbalanced forklifts in large logistics centers, require high-voltage and large-capacity batteries, such as 80V and 800Ah or above batteries, to ensure power and endurance.

Working environment: In a place with a good indoor environment and dedicated personnel responsible for battery maintenance, flooded lead-acid batteries are an economical choice. If in harsh environments, such as places with a lot of dust, significant vibration or where battery maintenance is inconvenient, sealed lead-acid batteries are more suitable, which can reduce maintenance workload and improve battery reliability.

Combined with the type of forklift

Small forklifts: Small electric forklifts such as electric pallet trucks and electric stackers, due to their compact structure and relatively low power demand, are suitable for batteries with lower voltages (24V - 36V) and capacities (100Ah - 300Ah), and are small in size, making them easy to install in limited Spaces.

Medium and large forklifts: Medium (2-3 tons) and large (over 3 tons) forklifts, to meet the demands of handling heavy loads and long-distance travel, need to be equipped with high-voltage (48V and above) and large-capacity (300Ah and above) batteries to provide sufficient power and longer driving range. At the same time, the compatibility of battery size with the forklift's battery compartment should be taken into consideration.

Conclusion

There are numerous parameters of lead-acid batteries for forklifts, and each parameter is interrelated and has a significant impact on the performance, service life and usage cost of forklifts. When choosing lead-acid batteries for forklifts, users must fully understand factors such as the working conditions, type, and their own cost budget of the forklift. They should comprehensively compare parameters such as rated voltage, rated capacity, external dimensions, discharge rate, and cycle life of different battery models to select the most suitable battery, so as to achieve efficient and stable operation of the forklift and reduce operating costs. With the continuous advancement of technology, lead-acid batteries are expected to achieve new breakthroughs in performance improvement and cost optimization, providing more powerful support for the development of the forklift industry.