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When The Battery Is Powered Off, Pay Attention To That Incorrect Operation Will Damage The Electrical Appliances

In the process of our daily vehicle maintenance and use, we often need to cut off the power of the battery, such as repairing electrical equipment, replacing the battery, leaving the vehicle idle for a long time, doing body welding, etc. However, this seemingly simple thing may cause damage to the vehicle if it is not operated properly.


Operation Specification In Case Of Battery Power Failure:

  • It is necessary to turn off the ignition switch before power failure, and turn off electrical equipment, such as audio and other equipment. Sudden power failure is prohibited when electrical equipment is running.

  • Power off sequence: from the perspective of safety, pull out the negative pole first. It is just the opposite during installation. Install the positive pole first and then the negative pole.

Why disconnect the negative electrode first? The reasons are as follows:

  1. Why? If the positive pole is pulled out first, because the negative pole is grounded, that is, the metal truck body around the positive pole is negative, if the tool touches the nearby metal truck body when removing the positive pole wiring with a tool, it will cause a short circuit between the positive and negative poles of the battery.
  2.  If the negative electrode is pulled out first because the metal truck body around the negative electrode is connected with the negative electrode, even if the tool touches it, it will not produce any bad results. When the negative electrode is pulled out and the power is cut off, it will not be dangerous to pull out the positive electrode again.
  3. Remove the positive electrode first, there is a risk of burning the electrical components.
  4. In actual work, many people damage the circuit and burn the handle due to violating the operating procedures, because the positive and negative short-circuit current of the battery is very large, resulting in high temperature in an instant.

The Control Of Power Switch Has Various Forms

Many people may have this question. My truck is equipped with the main power switch. Do I still need to cut off the battery?

First of all, we should have an understanding of the main power switch. Its common forms are mechanical switches and electromagnetic switches. The forms and control circuits of different vehicles are not the same.

Taking Jinbei light truck as an example, its main power switch is mechanical and installed in series on the negative main grounding wire of the battery. Once the main power switch is disconnected, the power supply of the whole vehicle will also be cut off, and the overall structure is very simple.

Turning Off The Ignition Switch Is Unreliable And May Damage The Ecu
  • It should be pointed out that when the vehicle is carrying out welding and other operations, if the ignition switch is turned off alone, it is bound to damage the electronic control components on the vehicle, such as ECU, etc. The forum has had similar cases before.
  • Correct operation: first stop the engine and disconnect the main power switch. Disconnect the positive power line and negative power line of the battery (Note: negative before positive), and reliably connect the positive power line and negative power line before welding.

With the continuous development of automotive technology, many electronic devices with storage and memory function are more and more widely used in vehicles. If the battery of the vehicle is powered off directly, it may lead to the loss of ECU stored fault information, locking of audio anti-theft password, reset of clock information and other problems, and then bring trouble to the use and maintenance of the vehicle.

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