Explain in detail the detection method and specific application of lead-acid battery
2022 Jun 20 By admin 0 comment
  1. Parameter testing method of lead-acid battery

1.1 Several methods for judging the sufficient charge of lead-acid batteries
During the charging process of the battery, the voltage will gradually increase. Especially when the battery is fully charged, the following characteristic features are often exhibited. According to these characteristics, it can be judged that the battery is fully charged. (1) When the battery is charged, the electrolyte produces a large number of bubbles and forms a boiling state.
(2) When the battery is charging, use a multimeter to measure the voltage of each single cell to 2.4V-2.5v.
(3) When the battery is charging, the measured electrolyte density is consistent with the density specified in the manual. For more battery usage questions, please visit tycorun.com, where someone will answer your questions.

1.2 The method of detecting the capacity of lead-acid battery by discharge

Any battery can use the discharge method to detect its current capacity.
For a 12V/17A·h battery, it is normally discharged with a standard current of C/10 (1.8A) after it is fully charged, and stops discharging when its voltage drops to the termination voltage of 10.8V. Multiplying the discharge time by the discharge current is its current actual capacity.

The actual test shows that after the battery is fully charged, it is normally discharged with a current of 1.8A, and it will drop to 10.8v in 5h, so its current actual capacity is 1.8Ax5h=9A·h. It can be seen that the current actual capacity of the battery is reduced by half of its rated capacity. This indicates that the battery is faulty, resulting in a reduction in capacity.

Figure 1 - Internal resistance capacity test of electric vehicle battery
Figure 1 – Internal resistance capacity test of electric vehicle battery
  1. Application of lead battery

2.1 How to choose lead battery

When actually purchasing large and small batteries, the following methods can be used.
(1) It can be purchased according to the battery model and specification. The model determines the body size and electrode arrangement. Specifications determine rated voltage and rated capacity.
(2) When purchasing a battery, you must find out the charging voltage value it needs. There are also two types of charging voltages, cyclic use and floating charge backup, which are often marked on the battery shell. The charging voltage is also a requirement for the output voltage of the charger. Only when the charger meets the requirements can the charging be safe and reliable.

(3) Check the date of manufacture. The date of manufacture is often hot stamped on the plastic case or cover. Products with a storage period of less than half a year should be selected as far as possible. If the storage period of the battery is too long, the capacity will decrease and the charging time will be prolonged.

(4) When purchasing batteries, check the plastic shell, plastic cover and electrodes for displacement, deformation, rupture, leakage and loosening. It is a normal product that the shell emblem shrinks inward, but it means that there is a certain negative pressure inside the battery.

(5) When purchasing batteries, the voltage should be measured. Generally, when the battery is fully charged, the open circuit voltage of each cell should reach 2.1V-2.2V, that is to say, the open circuit voltage of the lead battery with a rated voltage of 6V should reach 6.3V-6.6V after being fully charged; the rated voltage of 12V The lead-acid battery should have a fully charged open circuit voltage of 12.6V-13.2V.

2.2 Precautions for the use of lead-acid batteries

In practice, whether it is a large battery, a small battery, or a square or round single cell, if the correct use and maintenance knowledge is lacking, the battery life will often be shortened or scrapped. Here are the precautions for using the battery to facilitate daily maintenance.

(1) The battery should be placed in a ventilated and dry place, and should be protected from exposure to sunlight, rain and frost cracking. The exterior should be kept clean and dry to avoid short circuit between electrodes or self-discharge.
(2) When the battery is connected to the charger or electrical load, the power switch should be disconnected first.
(3) During use, the positive and negative poles of the battery should be correctly connected to the positive and negative poles of the charger or electrical load, and must not be connected wrongly or reversely, and must not cause a short circuit.

(4) When the battery voltage in normal use is as low as 1.8V, it should be stopped immediately, and it should not be used for a long time. Otherwise, the battery will be deeply discharged or overdischarged, resulting in the plate bowling and softening failure. The capacity is reduced and the service life is shortened. Therefore, when the voltage of a single cell is as low as 1.8V, it should be charged in time, and the charged power should be 1.2 to 1.3 times of the discharged power.

(5) When charging the battery, the output voltage of the charger should be appropriately higher than the rated voltage of the battery. When charging, except for the sealed battery, all the plugs of the filling hole should be opened, and it should be ensured that the battery is fully charged each time, and at the same time, overcharging should be prevented.

(6) When charging, the battery should be conventionally charged with a current of C/10.
(7) After the battery used in circulation is fully charged, its single cell voltage should be in the range of 2.4V-2.5V, then the open circuit voltage of two single cells in series should be 4.8V-5v, and the open circuit voltage of three cells in series should be 7.2V -7.5v, and so on.

(8) For the floating charge standby battery, the voltage of the single cell should be 2.1V-2.2v during charging, the floating charge voltage of two single cells in series should be doubled, and the floating charge voltage of three single cells in series should be tripled, and so on.

(9) For batteries that have been idle for a long time, supplementary charging and maintenance should be carried out frequently to ensure that the single-cell voltage of the battery is not lower than 2.2v.
(10) If the battery is rapidly charged with high current by increasing the voltage (the charging voltage applied to the single battery is higher than 2.5V), the charger must have the functions of self-checking and self-stop protection.

(11) In the charging place, avoid open flames or smoking, because the charging of the battery will generate flammable gas, so it should be avoided that the gas released by the battery will cause a fire. In addition, when using the battery, it should not be installed near the switch that is prone to sparks.

(12) During use, the vent hole of the liquid hole plug should be kept unblocked, because a large amount of hydrogen and oxygen will be generated inside the battery during charging and discharging. If the vent hole is blocked, it will inevitably cause the battery to burst.

(13) For batteries that are put on hold after use, they should be charged at least once a month to prevent the vulcanization of the plates due to lack of electricity.
(14) When the battery is in use, the height of the electrolyte should be checked frequently. When normal, the liquid level should be about 5mm-15mm higher than the protective net or the pole plate to prevent the pole plate from being exposed to the air and causing vulcanization failure.

(15) When the electrolyte of the battery drops, distilled water should be added instead of river water, well water or tap water to prevent metal impurities from being brought into the electrolyte and causing the battery to self-discharge.
(16) During the use of the battery, the density of the electrolyte should be adjusted according to the season. The density of the electrolyte should be kept at 1.15g/cm³-1.18g/cm³ in summer; 1.18g/cm³~1.20g/cm³ in autumn; 1.28g/cm³ in winter; Concentrated, so just add distilled water gradually. It is also necessary to prevent the electrolyte from freezing in winter and cause the active material of the plate to expand and fall off. In summer, the temperature is high, and it is necessary to prevent the vulcanization of the plate due to the excessive concentration of the electrolyte.

(17) When detecting the power storage level of the car battery, it can be judged according to the brightness of the light, and do not use the short-circuit method of starting the car to detect it. Otherwise, the depleted battery will easily cause the plate to bend due to high current discharge.

(18) A thin layer of Vaseline or butter should be applied to the surface of the battery pole and other metal parts to prevent the electrolyte from overflowing and corroding.
(19) The connection wires on the battery must be firmly connected. If loose, they must be reinforced in time. For small sealed batteries, the lead wire should not be heated and welded directly on the electrode, and the electrode should not be bent.

(20) When loading, unloading or moving the battery, do not tilt it, do not twist the pole with wire cutters, and do not drag it on the ground, so as not to damage the battery, parts or slaughter the electrolyte and damage the clothes.
(21) When the battery is used in a motor vehicle or other equipment, it must be firmly installed in the frame. When there is vibration, a shock pad must be installed to prevent the active material on the plate from falling off due to strong vibration.

(22) The ambient temperature of the battery should be kept in the range of -15℃-40℃, the surface temperature should not exceed 45℃, and it should not be installed close to the heating element such as the transformer.
(23) During use, batteries with different capacities, new and old batteries, and batteries made by different manufacturers should not be mixed.

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