The first thing to do is to cut off the power. Before the power is cut off, the ignition switch should be turned off. At the same time, the electrical equipment, such as audio equipment, should be turned off. The specific power-off sequence is as follows: safety first, so in maintenance, first pull out the negative pole, and then pull out the positive pole. When installing, the sequence is the opposite, first install the positive pole, then install the negative pole. Some friends will ask: why cut off the negative pole first? Here, I'd like to explain to you:

1、先拆正極存在燒壞電器元件的風險，容易引起電腦板燒毀的損失。在電路的實際維修過程中因違反操作規程，損壞電路和把手燒傷的人很多，因為蓄電池正負極短路電流非常大，能瞬間產生高溫。

1. First remove the positive electrode, there is a risk of burning out the electrical components, which is easy to cause the loss of computer board. In the actual maintenance process of the circuit, there are many people who damage the circuit and burn the handle because of violating the operation rules. Because the short-circuit current of the positive and negative electrodes of the battery is very large, it can produce high temperature instantly.

2、如果先拔掉正極，因負極是搭鐵的，也就是正極周圍的金屬車體都是負極，如果用工具拆卸正極接線時，工具碰到旁邊的金屬車體，就會造成蓄電池正負極短路。

2. If the positive pole is pulled out first, because the negative pole is grounded, that is, the metal body around the positive pole is all negative pole. If the tool touches the metal body beside the positive electrode when removing the positive connection with a tool, it will cause a short circuit between the positive and negative poles of the battery.

3、如果先拔掉負極，因負極周圍的金屬車體與負極是連通的，即使工具碰到也不會產生什么壞的結果，當負極拔掉后已經斷電，再去拔正極就不會有什么危險了。

3. If you pull out the negative pole first, because the metal body around the negative pole is connected with the negative pole, even if the tool touches it, it will not produce any bad results. When the negative pole is pulled out and the power has been cut off, it will not be dangerous to pull the positive pole again.

在這里要注意一點：現行的攪拌車的蓄電池都是有總開關的，但是原來的都沒有，就不好操作；而且如果是危險品運輸車，比如油罐車，車上的行車記錄儀是不允許斷電的，斷電后行車記錄儀不能工作，車主可能就要承擔法律責任了，但是我覺得如果是危險品運輸車，可以在車上放置一個供行車記錄儀的備用電源，這樣即使電路出現故障，也不至于讓行車記錄儀斷電了。如果你的攪拌車電路出現問題，一定要注意以上這些問題哦！

Here we should pay attention to one point: the battery of the current mixer truck is equipped with a master switch, but the original one is not available, so it is not easy to operate; moreover, if it is a dangerous goods transport vehicle, such as an oil tank vehicle, the vehicle's tachograph is not allowed to be powered off. After the power failure, the vehicle owner may have to bear legal responsibility, but I think if it is dangerous goods transportation A backup power supply for the tachograph can be placed on the car, so that even if the circuit fails, the tachograph will not be cut off. If your mixer circuit problems, must pay attention to the above problems Oh!