In today’s era of advanced technology, special vehicles are often equipped with a growing number of electronically controlled fuel injection engines. As a result, in the daily vehicle maintenance process, circuit maintenance operations have become increasingly common. Truck-mounted crane driver Master Li has shared his experiences, highlighting that activities such as repairing electrical equipment, replacing batteries, dealing with vehicles that are idle for a long time, and performing body welding can all involve circuit maintenance. However, what may seem like simple tasks can potentially cause significant secondary damage to the vehicle if not carried out properly.
Operating specifications when disconnecting the battery are of utmost importance. Before disconnecting the power supply, it is essential to ensure that the ignition switch is turned off. Additionally, all electrical equipment such as audio systems must also be turned off. Sudden power failures when electrical equipment is in operation can have serious consequences. Imagine a scenario where a vehicle’s audio system is playing music loudly, and without proper precautions, the power is suddenly disconnected. This can not only damage the audio equipment itself but may also cause disruptions to other electrical systems in the vehicle.
The disconnection sequence is a critical aspect of battery maintenance. From a safety perspective, during maintenance operations, it is advisable to disconnect the negative pole first and then the positive pole. Conversely, during installation, the sequence should be reversed, with the positive pole installed first and then the negative pole. This seemingly simple procedure has profound implications for the safety and integrity of the vehicle’s electrical system.
Let’s explore why disconnecting the negative pole first is so crucial. Firstly, if the positive pole is disconnected first, there is a significant risk. Since the negative pole is grounded, meaning the metal vehicle body around the positive pole is all negative. When using tools to disassemble the positive pole wiring, if the tool accidentally touches the adjacent metal vehicle body, it can cause a short circuit between the positive and negative poles of the battery. This short circuit can generate a large amount of electrical current in an instant, potentially leading to damage to the battery, wiring, and even other electrical components.
For example, picture a mechanic working on a truck’s electrical system. If they disconnect the positive pole first without being careful, and their tool slips and makes contact with the metal body of the truck, a short circuit can occur. The resulting spark and high electrical current can cause damage to the battery terminals, melt wiring insulation, and even start a fire in extreme cases.
On the other hand, if the negative pole is disconnected first, the situation is much safer. Since the metal vehicle body around the negative pole is already connected to the negative pole, even if a tool touches it, there will be no adverse consequences. Once the negative pole is disconnected and the power is off, disconnecting the positive pole poses minimal risk.
Moreover, disconnecting the positive pole first poses a significant risk of burning out electrical components. In particular, it is highly likely to cause damage to the computer board. The computer board in modern vehicles is a critical component that controls various aspects of the vehicle’s operation, including engine management, transmission control, and safety systems. Damage to the computer board can lead to costly repairs and significant downtime.
In actual work, many people have unfortunately damaged circuits and even burned their hands due to violations of operating procedures. The short-circuit current between the positive and negative poles of the battery is extremely large and can generate high temperatures instantly. This not only poses a danger to the person performing the maintenance but can also cause extensive damage to the vehicle’s electrical system.
It should be noted that many trucks in China do not have a main power switch. This is due to the legal requirement that the driving recorder on the truck cannot be powered off. If the power is cut off and the battery happens to be exhausted, and the driving recorder cannot function, legal liability may be incurred. Although there are various forms of power switches available on trucks at present, it is still highly recommended to disconnect the battery according to the proper maintenance operating procedures when performing maintenance operations, especially during body welding. Body welding involves high temperatures and electrical currents, and if not done carefully, it can cause severe damage to the vehicle’s electrical equipment.
For instance, if a truck is being welded without proper precautions, the electrical currents generated by the welding process can find their way into the vehicle’s electrical system through various paths. This can damage sensitive electrical components such as sensors, relays, and control modules. By disconnecting the battery according to the correct procedure, the risk of electrical damage during welding can be significantly reduced.
In conclusion, when it comes to the circuit maintenance ofspecial vehicles, following the correct operating procedures for disconnecting and reconnecting the battery is essential. Understanding the importance of disconnecting the negative pole first and being cautious when working with electrical systems can help prevent costly damage and ensure the safety and reliability of the vehicle. Whether it’s repairing electrical equipment, replacing batteries, or performing other maintenance tasks that involve the vehicle’s electrical system, taking the time to follow proper procedures can go a long way in protecting the vehicle and avoiding potential legal issues.
