Recently, when I was surfing the Internet, I came across a media man @ uncle xiaote. When he was using an electric car, he encountered the situation that the small battery was dead and the car couldn’t start. The funny thing is that the car has been plugged into a charging pile.

In fact, we have encountered this situation ourselves. When testing geometry C and Xiaopeng G3, Dianbang forgot to turn off the headlights after the trailer, so that the small battery ran out after the trailer drove to the charging station.

Then the problem came. We couldn’t get off the trailer! When you get off the trailer, you need to put in neutral gear, but G3 is an electronic gear. Geometry C is a knob type. When the small battery runs out of power, they will collapse directly. There is no way but to take the power Bao’an platoon.

Oh, by the way, I don’t know why the small battery is dead, and the large battery can’t be charged quickly.

It’s ridiculous for me to say this. What kind of model worker is a small battery? Need it everywhere? So today I’ll tell you about the small battery!

What does a small battery do?

The scientific name of small battery is battery. In a fuel vehicle, if the engine wants to start, it needs to be driven by the starter, while small battery supplies power to the starter.

For electric vehicles, there is no need for the starter to drive the engine to start, so there is no need for small battery power supply. But small batteries also play a role in electric vehicles.

We know that electric vehicles have two sets of electrical systems: high voltage and low voltage. The high voltage part is a large battery, which is mainly used to drive cars; The low-voltage electrical system is a small battery, which is usually used in the low-power subsystem of the car, such as door, window, lamp, etc.

For example, the embarrassing situation mentioned above is caused by not turning off the headlights, which also proves that the small battery is indeed supplying power to these low-voltage parts.

In addition, the small battery also works part-time to turn on the switch of high-voltage system and BMS power supply.

What happens when the battery runs out?

In fact, from the above, we can find that the biggest problem caused by the lack of power of the small battery is the car lying down, and the inability to open the door with the remote key.

For electric vehicles, it sometimes leads to failure to charge large batteries. Some friends may want to ask, can’t you charge your small battery because your big battery is full?

If you are an electric car, you can’t charge the small battery with the large battery. Why should you charge the small battery with the large battery?

In fact, many large batteries of electric vehicles can charge small batteries, but their logic is different. Some cars can only charge the small battery when starting. At this time, if you turn off the engine again, the large battery will not care about the life and death of the small battery.

At this time, even if the large battery is charging, the small battery is still in a dead or low state.

In addition, some models, such as BYD’s products, can also charge small batteries when the engine is off. Therefore, as long as the large battery has electricity, it can ensure that the small battery is safe.

What's the use of electric vehicle batteries? How to maintain?

Excerpt from BYD Han user manual

How to solve and prevent? It is recommended that you learn how to get on the electricity by yourself.

This thing is not difficult. There are always wires in the car, or a treasure can buy a power treasure, or grab another car. Then remember the formula “positive to positive, first positive, negative to negative, then negative, first negative, then positive”.

The picture below shows us powering up Xiaopeng G3:

What's the use of electric vehicle batteries? How to maintain?

The following figure shows the small battery of Xiaopeng G3, and the positive pole is drawn in the red box.

What's the use of electric vehicle batteries? How to maintain?

As for how to prevent, first of all, whether fuel vehicles or electric vehicles, we should try to avoid not starting the car for a long time.

For example, during the epidemic, some people didn’t go out for several months. When the epidemic improved, they were ready to drive, but they found that the car couldn’t start.

In this case, we suggest you start the car every three or five times. If your car has remote start function, just move your hand at home and turn on the air conditioner for more than ten minutes.

Secondly, try to avoid behaviors like forgetting to turn off the lights, turning off the central control screen and so on.

No, I’ve already eaten it. I’ll never do it again next time. However, at present, many electric vehicles adopt the design logic of getting on and off without feeling. There is no one click Start button, and there is no need to start and turn off. It is very convenient for people to walk and cool the car.

Third, for electric vehicles, try to avoid the limit state of large battery and small battery running out at the same time. For example, in our endurance test environment, at this time, the large battery needs the help of the small battery to start the charging function. The small battery is still waiting for the large battery to charge it. Both of them have no power. They really have to stare and ask for external help.

State comments

The above is the function and precautions of electric vehicle small battery. In fact, there are many small problems in the actual use of electric vehicle. If you have any problems about car use or unclear principles, you can leave a message to Mr. bang, and we will help you solve them.

Editor ajx

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