Forklift lead-acid battery "strike"? How to accurately locate current faults from the perspective of circuit design

How to accurately locate current faults from the perspective of circuit design

Time：2025-03-07 15:38:06

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When the forklift lead-acid battery has a problem, the accurate location of the current fault from the perspective of circuit design is the key to quickly solve the problem and restore the normal operation of the forklift.

In the field of warehousing logistics, industrial production and other fields, forklifts are indispensable handling equipment, and lead-acid batteries as its main power source, once the "strike" will seriously affect the efficiency of the operation. When the forklift lead-acid battery has a problem, the accurate location of the current fault from the perspective of circuit design is the key to quickly solve the problem and restore the normal operation of the forklift.

First, understand the basic architecture of forklift lead-acid battery circuit

Forklift lead-acid battery circuitry seems complex, but it actually follows basic electrical principles. Its core components include the battery pack, the controller, the motor and the wires connecting them and various electronic components. The battery pack consists of multiple lead-acid batteries in series or parallel to provide the direct current required for the operation of the forklift. As the "commander" of the circuit, the controller receives the operation instructions of the driver, accurately adjusts the output current of the battery according to the operation state of the forklift, and then controls the speed and torque of the motor to realize the forward, backward, lifting and other actions of the forklift. The motor is the executive part that converts electrical energy into mechanical energy, driving the operation of the forklift and the fork work.

In this circuit system, the current starts from the positive electrode of the battery, flows through the controller, the motor and other loads, and returns to the negative electrode of the battery to form a complete loop. Each part is closely coordinated, and the failure of any link may cause current abnormalities, resulting in a battery "strike".

Second, common current fault phenomena and circuit design correlation

(1) The battery cannot output current

When the forklift starts with the key inserted, there is no reaction, and the battery seems to be completely "out of power". Judging from the circuit design, it may be that the battery pack internal connection line is broken. The lead-acid battery is used for a long time, and the connection is easy to loosen and break due to vibration, corrosion and other reasons. For example, if the screw between the battery pole and the connecting clamp is loosened, the contact resistance will increase sharply, preventing current transmission, resulting in a battery that is charged but cannot be output. In addition, a blown fuse in the controller can also cause such a failure. The fuse plays an overload protection role in the circuit, if the motor instantaneous starting current is too large, exceeding the rated current of the fuse, the fuse will be blown, cut off the circuit, so that the battery can not output current.

(2) The current output is unstable

During the operation of the forklift, the power is suddenly strong and weak, and the speed is fast and slow, which indicates that the battery current output is unstable. From the perspective of circuit design, the power transistor in the controller may be damaged. The power transistor is responsible for regulating the size of the current, if the performance of some of its components is reduced or there is a short circuit or open circuit, it will lead to the abnormal regulation of the current and the output current fluctuations. In addition, the motor brush wear will also cause current instability. The brush is in close contact with the motor commutator to transfer the current. Uneven brush wear will make the contact resistance unstable, which will affect the input current of the motor and cause the output current of the battery to fluctuate.

(3) Abnormal current during battery charging

When charging the lead-acid battery of the forklift truck, if the charging current is too large or too small, or even unable to charge, it is also related to the circuit design. The charging controller in the charging circuit plays a key role. When the voltage detection circuit of the charge controller fails, the battery voltage cannot be accurately detected, and the charge current may be incorrectly controlled. For example, the voltage detection circuit components aging, the detected battery voltage is low, the charging controller will mistakenly think that the battery power is seriously insufficient, thereby increasing the charging current, resulting in excessive charging current; On the contrary, if the voltage is detected to be abnormally high, it will reduce the charging current or even stop charging, resulting in no normal charging.

Third,methods and tools for accurately locating current faults

(1) Visual inspection method

When a current fault is suspected, a visual inspection of the circuit is performed first. Carefully check whether the external connection lines of the battery pack are damaged, broken, and loose, and check whether the connection points have corrosion, heat and discoloration. For the controller, motor and other parts, observe the shell for deformation and burn marks. Although this method is simple, it can quickly find some obvious circuit faults, such as line break, component burn and so on.

(2) Multimeter detection method

A multimeter is a common tool for locating current faults. Measuring the battery voltage can initially determine the battery power and whether there is an internal short circuit and other problems. Set the multimeter to DC voltage, and connect the pen to the positive and negative terminals of the battery respectively. Under normal circumstances, the voltage of the fully charged lead-acid battery pack should be close to its nominal voltage. If the measured voltage is significantly lower, the battery may be low or faulty. When measuring circuit current, connect the multimeter to the circuit in series. For example, to detect the working current of the motor, you can disconnect one of the connection lines between the motor and the controller, connect the red pen of the multimeter to the power side, and the black pen to the motor side, adjust to the appropriate current gear, and start the forklift. At this time, the value displayed by the multimeter is the working current of the motor. By comparing with the rated current of the motor, determine whether the current is normal. If the current is too large, the motor may have short circuit or mechanical lag; If the current is too small, there may be a circuit break or poor contact.

(3) oscilloscope analysis

For some complicated current fluctuation faults, oscilloscope can play an important role. Oscilloscope can directly display the waveform of current and voltage change with time in the circuit. Connect the probe of the oscilloscope to the key nodes of the circuit, such as the controller output, the motor input, etc., and start the forklift operation. Under normal circumstances, the current waveform should be smooth and regular. If the waveform spikes, burrs, and fluctuations are abnormal, you can analyze the fault cause according to the waveform characteristics. For example, sharp pulses appear in the waveform, there may be electromagnetic interference in the circuit; The waveform fluctuates greatly, which may be the controller's abnormal current regulation.

Through the in-depth understanding of the forklift lead-acid battery circuit design, combined with the analysis of common current fault phenomena, and the use of appropriate detection methods and tools, the current fault can be accurately located and timely repaired to ensure the stable and reliable operation of the forklift lead-acid battery and ensure the efficient operation of the forklift.

Statement: The articles on this site are written by the GSGT team or reprinted from other media or compiled by AI.No reproduction without permission.For copyright or other issues, please contact:gsgtpower@163.com.

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