Several effective ways to extend the lifespan of batteries used in construction machinery

I. Forms of Battery Damage

Most of the faults that occur during the use of storage batteries are caused by improper maintenance and usage. External faults of the battery include cracks in the shell and cover, dry and cracked sealing glue, loose and corroded terminal posts, etc. Internal faults include plate sulfation, self-discharge, internal short circuit, active material shedding, and plate arching, etc.

When in use, the main precautions should be taken to prevent excessive discharge and overcharging. Excessive discharge will cause sulfation of the plates, and the active substances on the plates form white PbSO4 crystals that cannot participate in chemical reactions. This is one of the reasons for the early damage of the battery. At the same time, due to excessive discharge caused by high current, such as using the starter too much or discharging at high current for too long without timely supplementary charging, the plates will arch and the separators will be damaged, putting the battery in a poor state. When overcharged, electrical energy electrolyzes water, generating hydrogen and oxygen, which creates a certain pressure in the pores of the plates, causing the active material on the plates to fall off and become irreparable.

Ii. Factors Affecting Battery Capacity

The factors influencing the capacity of a storage battery include the structure of the plates, the magnitude of the discharge current, the temperature of the electrolyte and the density of the electrolyte, among which the charging and discharging current and the temperature have the greatest impact. If the charging and discharging current is too large, it will cause the active material on the plates to change on the surface, and the capacity will be greatly reduced. Meanwhile, the drop in temperature will lead to poor fluidity of the electrolyte, plate contraction, slow chemical changes, and an increase in the internal resistance of the battery. At 30℃, if the temperature drops by 1℃, the capacity will decrease by about 1%, and its internal resistance will also increase. So in extremely cold regions, when the temperature drops below -20℃, the capacity has already dropped to 60%, the internal resistance has increased, the engine often fails to start, and one often feels that the battery power is insufficient. In extremely cold regions, excessive discharge is prone to occur, while in temperate regions, the problem of excessive charging often happens. Therefore, to use the storage battery well, it is necessary to master its usage rules based on the local climate conditions and the actual situation. The charging of storage batteries must be carried out by choosing appropriate methods and using charging equipment correctly according to different situations. Only in this way can the capacity of the storage battery be increased and its service life be prolonged.

Iii. Common Charging Methods for Storage Batteries

Common charging methods include constant current charging, constant voltage charging and pulse fast charging. Batteries in use often have the phenomenon of insufficient charging and need to be replenished regularly. To maintain a certain capacity of the battery and extend its lifespan, overcharging and cycle exercise charging are required. To eliminate the sulfidation fault of the plates, it is necessary to carry out sulfidation removal and charging, etc. The charging current in the first stage of initial charging is 1/15 of its rated capacity. The charging current is halved in the second stage. In the first stage of supplementary charging, the charging current is 1/10 of its rated capacity, and in the second stage, it is reduced to half. The characteristic of a fully charged lead-acid battery is that the terminal voltage rises to a maximum of approximately 2.7v and does not increase further within 2 to 3 hours. A large number of bubbles are produced inside the battery and the electrolyte boils.

Iv. Correct Use and Maintenance of Storage Batteries

The correct use and maintenance of storage batteries include:

1. Analyze the power consumption of the machinery and keep the terminal voltage of the generator within the specified range. For instance, for machinery that often operates during the day, the charging time is long and the discharging time is short. To prevent the problem of overcharging, the charging current should be appropriately reduced. For machinery that operates at night and vehicles that start frequently, to prevent excessive discharge, efforts should be made to appropriately increase the charging current. It should be fully charged when parked for the next use

2. Pay attention to the temperature conditions during the operation of machinery or vehicles. In cold regions, it is essential to pay attention to the insulation of the battery and rationally select the density of the electrolyte to keep it in a fully charged state. Distilled water should be added during charging to prevent freezing. Before starting, the engine should be preheated and the starter should be used correctly. Each start should not exceed 5 seconds, and there should be a 15-second interval before starting again. If it fails to start twice in a row, the fault should be eliminated before starting again.

3. Strengthen the maintenance of the battery. If the battery is only used without maintenance, and the working conditions are poor (with large vibrations and dust pollution), the consequences are obvious.

The maintenance contents of the battery include:

① Keep the exterior of the battery clean. Regularly remove the dust, dirt and spilled electrolyte from the battery cover to help prevent self-discharge.

② Regularly check the small holes on the battery cover to keep them unobstructed. If the small hole is blocked, the gas produced will burst the battery.

③ The installation of the battery must be reliable. When the machinery is jolting on an uneven road, the battery must not move up, down, left or right in the installation seat or collide with it. Rubber shock-absorbing gaskets should be placed at the bottom of the battery to prevent the shell from cracking, the connection terminals from loosening and the internal plates from being damaged. In addition to checking for a firm installation, it is also necessary to pay attention to removing oxides, sulfates and other substances produced by the battery clips. Vaseline can be applied after cleaning and scraping off the rust to prevent further rusting. Regularly inspect the wire joints to ensure reliable contact.

④ Regularly check the height of the electrolyte level. The electrolyte in the battery will decrease as it decomposes and naturally evaporates during charging. Once the plates are exposed above the liquid surface, the exposed parts will be quickly sulfated, thereby reducing the battery's capacity. Even if the electrolyte is added and then submerged, the sulfated plates are difficult to return to their original state. Therefore, it is necessary to check the liquid level in the battery in a timely manner and add distilled water or electrolyte as appropriate. Generally, it should be checked once a week in summer and once every two weeks in winter. The battery with a semi-transparent plastic casing allows the internal liquid level height to be seen from the outside of the casing. There are also two marking lines on the casing, upper and lower. As long as the liquid level height is between these two marking lines, it is acceptable. For batteries with black plastic casings, when inspecting, you need to unscrew the liquid filling cap, observe with your eyes and estimate the liquid level height. You can also insert a small glass tube into the battery, press the upper opening of the glass tube with your finger, and take out the electrolyte for inspection. Under normal circumstances, the height of the electrolyte level should be 10 to 15mm above the plates. When the liquid level is found to be too low, distilled water should be added to make up for it. If the electrolyte is poured out or overflows, additional electrolyte should be added. It should be noted that ordinary water such as tap water, river water and well water cannot be added as distilled water.

⑤ Regularly check the relative density of the electrolyte. If a significant amount of water shortage is found, one should consider whether overcharging is necessary. If the density is found to be too low, it is necessary to consider whether there is excessive discharge and supplementary charging should be carried out.

⑥ In winter, it is necessary to keep the battery warm to prevent it from cracking due to freezing, which can extend its service life.