Analysis and elimination of common malfunction of battery
Author: Yan binghui
Source:”Agricultural Machinery Use and Maintenance” 2017 06 Issue
Abstract:Explains the external manifestations of common malfunctions of batteries and the causes of malfunctions, reminding users to pay attention to precautions in use to avoid battery failures.
Key words: battery; common malfunctions; agricultural machinery
Chinese library classification number:U7424
Document identification code:A
Various faults occur in the battery using, which can be attributed to two types of internal faults and external faults. Common external faults include: shell cracks, dry sealant cracks, loose wiring or poor contact, and electrical pile corrosion. Internal faults include: plate vulcanization, plate active material shedding, self-discharge and plate short circuit and open circuit, etc. Once the above-mentioned fault occurs in the battery, the following phenomena will occur during use.
1.Battery Loss
When starting the engine, the starter speed is low or unable to rotate; the light is dim and red; the sound of pressing the horn is low and hoarse. When checking the battery, the electrolyte specific gravity is less than 1.50, and the single cell voltage is less than 1.7 V.The reasons for the battery loss are as follows:(1)High current discharge. Starting the engine for a long time will make the battery high current discharge time too long, causing the white coarse-grained lead sulfate formed by the active material on the pole plate to be difficult to reduce, which is called sulfidation, which causes the battery to lose power.(2)The charging current is too small. Due to the fault of the generator or the voltage regulator, the charging current of the generator to the battery is too small for a long time, and it cannot supplement the consumption caused by the discharge of the battery, causing the battery to lose power.(3)Insufficient electrolyte. Due to insufficient electrolyte addition, the electrode plate is exposed to the surface of the liquid, which reduces the area that participates in the chemical reaction in the electrolyte, and the capacity of the battery decreases and the battery loses electricity.(4)Self-discharge causes the battery to lose power. The lack of battery power not only affects the normal operation of the tractor, but also causes early damage to the battery. Therefore, it should be carefully maintained during use, and if there is a power loss, it should be recharged immediately.
2.The battery is not charging
The capacity of the battery is sufficient, and the voltage is equal to the charging voltage of the generator. At this time, the battery cannot be charged (the ammeter pointer points to 0) is a normal phenomenon. When the battery is running low and the generator is working normally, there is no charging current, which is a fault phenomenon. The reasons are as following:(1)The battery cell is short-circuited. The engine is difficult to start or unable to start. When starting, the temperature at the single-cell short circuit rises sharply, and the electrolyte boils and overflows. The single-cell short-circuit is mainly caused by long-term high-current discharge, and the expansion of the active material causes the plate to warp, causing activation The material falls off. If this fault is found, it should be repaired or replaced in time.(2）Poor contact of electric posts. Due to the corrosion of the electrolyte, a layer of oxide is formed on the surface of the electric pile, which causes poor contact of the wire joints, loose joints, and excessive contact resistance, which will also prevent the battery from being well charged, and will ablate the electric pile head in severe cases.
3.Battery electrolyte consumption is too fast
The main reasons for the excessive consumption of battery electrolyte are：(1)The battery shell ruptures due to bumps and vibrations when the tractor is working, causing electrolyte leakage,which resulted in consumption.(2)The screw plug of the filling hole is not tightened, and electrolyte spills from the filling hole when the tractor is working.(3)Excessive charging current or vulcanization of the electrode plates will cause the internal temperature of the battery to rise, and the electrolyte will evaporate outward due to a large number of bubbles generated by the boiling, which will accelerate the consumption of the electrolyte.
If the lysate is consumed too fast, the liquid level will be lowered, and the electrode plates will be exposed. If it is not added in time, it will reduce the area of the electrode plate to participate in the chemical reaction, reduce the battery capacity, and oxidize the exposed electrode plate, causing the battery electrode plate to be vulcanized and early damage.
If find that the electrolyte is reduced. If it is determined that it is not caused by leakage or spilling, add an appropriate amount of electrolyte and maintain a normal specific gravity. If the evaporation is reduced, distilled water should be added to avoid excessive electrolyte concentration and accelerate the process of vulcanization and corrosion of the electrode plate. Due to the natural evaporation of the electrolyte, in the case of high ambient temperature, an appropriate amount of distilled water should be added every 30 to 50 hours of work.
4.Battery Self Discharge
It is normal for the battery to gradually decrease in capacity after being left for a period of time after charging. If the power disappears quickly, or even disappears quickly after being sufficient, this is a malfunction, which is called self-discharge. The battery with severe self-discharge should be replaced with a plate or a new battery.(1)The surface of the battery cover is contaminated by the electrolyte and dust spilled from the bumps, forming a current path between the positive and negative electrodes. Therefore, always keep the battery surface clean. The outer surface of the battery should be frequently rinsed with hot water and wiped dry to keep it clean and dry; the cover of the battery should be tight to prevent the electrolyte from splashing out and impurities falling in.(2)The electrolyte is impure or mixed with metal conductors, causing a loop between the impurities or between the impurities and the plates, causing the battery to self-discharge. Special sulfuric acid (colorless and transparent) and distilled water must be used to prepare the electrolyte; the utensils for preparing and storing the electrolyte should be made of acid-resistant materials such as ceramics and glass; the prepared electrolyte must be properly stored to prevent impurities from being mixed in.(3)The plate is damaged. Due to high-current discharge or charging, the electrode plates will be warped due to the expansion of the active material, causing the active material to fall off, or the separator may be damaged and cause a local short circuit, which will also cause the battery to discharge itself.(4)If the electrolyte has a high specific gravity, the active material on the electrode plate will be corroded and fall off. The fallen off material will settle on the bottom of the battery. Excessive sediment will form a local short circuit between the electrode plates, so the battery will discharge by itself.(5)If the storage battery is not used for a long time, the sulfuric acid in the electrolyte will cause the density of the electrolyte to be inconsistent between the upper and lower sides, and the potential difference will be formed on the electrode plate, which will cause self-discharge.
5.Internal Short Circuit
The internal short circuit of the battery is manifested as the battery open terminal voltage is too low, the starter is weak, or the voltage drops rapidly when starting; during charging, the relative density of the electrolyte of a single cell rises very slowly, and there are few bubbles at the end of the charge, and the temperature rises very much. Fast, the voltage is very low or zero. The reasons for the internal short circuit are:(1)The battery is seriously overcharged or the charging temperature is too high, causing the active material on the plate to fall off, forming a short circuit;(2)Excessive high-current discharge during use, followed by high-current charging, resulting in sharp bending and deformation of the plate, causing the active material to fall off;(3)The separator is corrupted, the electrolyte is not clean, or the sediment accumulates excessively during long-term use.
To eliminate the battery short-circuit fault, disassemble each cell, take out the plate assembly and immerse it in distilled water, clean the sediment at the bottom of the cell shell of each cell, replace with a new separator and check whether there are conductive impurities sandwiched between the positive and negative plates. . After cleaning, re-install the plate into the battery case, add a dilute electrolyte for charging, and check the charging and discharging with a 10 h discharge rate, then charge again, and adjust the electrolyte’s specific gravity to a normal state.
6.Conclusion
During the use of agricultural machinery and equipment, we often encounter the battery not working normally. We need to understand the common faults of the battery and what are the causes, so that we can pay attention to avoid damaging the battery in actual work; when the battery fails , Can also be targeted at troubleshooting.