Car Care: Battery Details

The battery is the main energy storage device on the vehicle and provides power for all electronic systems on the vehicle. Modern automobiles are becoming more and more electronic, and the lack of battery power will lead to vehicle defects.

Battery type:

The battery used in general cars is a lead-acid battery. There are two types of common lead-acid batteries. One is a water-based lead-acid battery, and the other is a maintenance-free lead-acid battery.

Water-adding lead-acid batteries: The plates of ordinary batteries are composed of lead and lead oxides, and the electrolyte is an aqueous solution of sulfuric acid. Its main advantages are its stable voltage and low price; its disadvantages are its low specific energy (ie the electrical energy stored per kilogram of battery), its short service life, and its frequent maintenance.

Maintenance-free lead-acid battery: maintenance-free battery due to its own structural advantages, the consumption of electrolyte is very small, basically do not need to add distilled water during the service life. It also has the characteristics of shock resistance, high temperature resistance, small size and small self-discharge. The service life is generally twice that of ordinary batteries. There are also two kinds of maintenance-free storage batteries on the market: the first one is used for adding electrolyte at the time of purchase and no maintenance is required after use (adding replenisher); the other is that the battery itself has been added with electrolyte and sealed Users simply cannot add supplemental fluids.

Battery maintenance method:

After more than 2 years of use of batteries for cars, capacity and discharge capacity will decrease. General vehicle battery life will not exceed 4 years. Of course, a well-maintained battery will last longer. Let's learn about the maintenance methods for water-adding lead-acid batteries and maintenance-free lead-acid batteries.

Water-adding lead-acid batteries: Pay attention to the battery liquid level and the battery liquid density.

The lead-acid battery's battery fluid is a mixture of sulfuric acid and distilled water. When the battery discharges, the water will increase and the sulfuric acid will decrease, which will result in a decrease in the density of the battery liquid; when charging, on the contrary, the water will become less and the sulfuric acid will increase. The battery fluid concentration reflects the ratio of water and sulfuric acid in the battery fluid. The normal electrolyte density is 1.28 (summer)/1.29-1.30 (winter) (in grams per cubic centimeter).

As owners, we should check the battery liquid level regularly. Distilled water should be added to the proper level when the battery fluid is insufficient. After adding distilled water to the battery, we should check the battery fluid density and keep the battery fluid density within a reasonable range.

Maintenance-free lead-acid battery: Regularly check the eye and keep it charged

Due to the maintenance-free battery, there is no water filling hole and the battery liquid level scale. We need to judge the status of the battery through the "magic eye" on the battery. The green eye is green and the battery is normal. The charge is enough. The evil eye is black and needs to be charged. The evil eye is white and the battery needs to be replaced.

The discharge capacity requires the use of a dedicated battery tester.

We generally use a voltmeter to check the battery voltage. Although we can detect the battery voltage, we can't check the battery's load capacity. In order to check out the actual condition of the battery, we should use a dedicated battery tester to check the discharge capacity of the battery and its ability to carry the load.

Weak current cannot be ignored:

After the car is locked, the anti-theft system of the vehicle starts to work, and a weak current is drawn from the battery. Therefore, if you do not use the car for a long time, it will cause the battery to lose power. If it is found that the vehicle is short of power for a short period of time, in addition to checking the condition of the battery, it is also necessary to check whether the weak current when the vehicle is stationary is too large. The excessively high standing current of the vehicle is likely to be caused by part of the internal electrical wiring of the vehicle. If it is not handled early, it will lead to safety hazards. At the same time, excessive discharge of the battery for a long time will shorten its life. The automotive maintenance industry generally uses a clamp ammeter to detect the weak current when the vehicle is stationary.

How to deal with battery icing?

Since the battery fluid in the battery is water and sulfuric acid, the battery is likely to freeze at low temperatures. What happens when the battery icing happens?

First of all, we do not study whether battery liquid will freeze. Let's take a look at what should happen after the battery is frozen.

After the battery freezes, our vehicle will not start. We should remove the battery from the car, and then move it to a heated place in the room to allow the battery fluid to melt before loading it into the car. Of course, removing the battery at night to bring it to a warm place in the house can prevent the battery from freezing.

Will the battery freeze?

The battery will freeze in the following situations:

1) Adding too much distilled water leads to a decrease in the battery fluid density. At this time, the increase in the percentage of water in the battery fluid leads to an increase in the freezing point of the battery fluid.

2) Excessive discharge leads to a drop in the density of the electrolyte, and the imbalance between the ratio of sulfuric acid and water causes the freezing point of the battery liquid to rise.

What is the degree of freezing in the battery electrolyte?

The normal battery sulfuric acid concentration is 35%-40%. According to the "sulfuric acid-water mixture freezing point curve" we can know that the freezing point of the electrolyte is between -60 degrees Celsius and -50 degrees Celsius. From the data point of view, as long as the battery fluid density is maintained between 1.25-1.30, it is unlikely that there will be ice formation (unless you are using a car in very northern China).

However, as the concentration of sulfuric acid decreases, the freezing point of the battery fluid rises with it, which makes it possible for the battery fluid to freeze. For example, the winter minimum temperature in Beijing is generally at minus ten degrees, and when the battery fluid density is as low as 1.10, the battery may freeze. The most common cause of these changes is battery overdischarge.

How to avoid excessive battery discharge:

1) Avoid using high-power appliances while parking. High-power appliances include headlights, fog lamps, seat heating, audio, and air conditioning.

2) Check that the headlights and the interior roof lighting have been turned off before leaving. In general, a normal full-charged battery allows the headlamp to work for two hours. With the decrease of the rated capacity of the battery, the shorter the headlamps can work normally. If you forget to turn off the headlights after leaving the car, the vehicle's computer does not automatically turn off the lights. The chances of not getting a car the next morning are 99%.

3) Pull out the negative pole of the battery when it is not used for a long time. Due to the weak current consumption in the vehicle's circuit system due to parking, leaving the vehicle for a long time will cause the battery to run out. Therefore, for vehicles that are not used for a long time, we should pull down the negative pole of the battery to avoid excessive battery consumption.

to sum up:

In most areas of China, a good lead-acid battery will not cause icing. Owners and friends should usually pay more attention to the vehicle's battery, and regularly check the condition of the battery to avoid excessive battery discharge. If the battery has reached the end of its useful life and it is found that the vehicle has difficulty in starting up and the brightness of the headlights is insufficient, we suggest that owners should replace the battery as soon as possible.