Lead acid battery life is so short? That's because you still don't know this!
Battery inspection and maintenance
The maintenance work of the battery is indispensable. Whether it is manual operation or maintenance or automatic monitoring and management, it is to detect the abnormality of individual batteries or the equipment system failure that affects the battery charge and discharge performance in a timely manner, and actively take corrective measures to ensure the stability of the power supply system. Run reliably. Battery inspection and maintenance is divided into routine maintenance, quarterly maintenance and annual maintenance.
First, routine maintenance
1. Ensure that the battery surface is clean and dry;
2. Always pay attention to the changes in the ambient temperature of the battery system and the appearance of the battery;
3. Always check the battery float voltage and battery pack float voltage (terminal total voltage), and compare it with the panel display, and correct if necessary;
4. Ensure that the battery cabinet or battery compartment is clean, well ventilated or well lit.
Second, quarterly maintenance
1. Visually inspect the cleanliness of the outer surface of the battery, the integrity of the outer casing and the cover, whether the appearance of the battery changes with the deformation of the bulge, and whether the battery has any signs of overheating;
2. Every quarter at the unified detection point of the battery system, the ambient temperature of the battery system is detected and can represent the average temperature of the system. When the temperature is lower or higher than 25 °C, the temperature control system should be adjusted, if no temperature control system is installed. , should adjust the float voltage;
3. Measure and record the total voltage of the floating charge at the battery end, and compare it with the display value of the panel meter. If there is any difference, find the reason and correct it;
4. Measure and record the float voltage of each battery in the system. Under normal circumstances, it should fluctuate within a certain range. If an abnormality is found, find out the cause and correct it;
5. Perform a restorative discharge test, discharge with a dummy load or actual load, that is, cut off the power supply and supply power from the battery. After finding that the battery capacity is low, the battery is evenly charged. After the equalization and charging, the capacity cannot be restored. The battery with too low capacity should be replaced.
Third, annual maintenance
1. Repeat quarterly maintenance of all content;
2. Check the connection points between all the batteries and ensure that the connection is securely fastened;
3, freely extract a few batteries for internal resistance test, because the internal resistance of the battery and its capacity wireless relationship, so the internal resistance of the battery can not be used to directly indicate the exact capacity of the battery, but the internal resistance of the battery can be used as a "healthy" state of the battery Bad indication signal.
Several factors affecting battery life
1, deep discharge
The depth of discharge has a great influence on the cycle life of the battery. If the battery is frequently deeply discharged, the cycle life will be shortened. Because the deep discharge of the same rated capacity of the battery means that the current is often charged and discharged with a large current. When the current is discharged or is often under voltage, it cannot be recharged in time. The sulfate particles produced are large, and the active material of the plate cannot be Make full use of it, the actual capacity of the battery will gradually decrease over the long term, affecting the normal operation of the battery. Since solar photovoltaic power generation systems are generally less prone to overcharging, long-term depletion is the main cause of battery failure and life shortening in solar photovoltaic systems.
2, discharge rate
The capacity of the discharge rate generally specified for 20 hours is the rated capacity of the battery. If the discharge rate is lower than the specified hour, the battery capacity higher than the rated value can be obtained; if the discharge rate is higher than the specified hour, the discharged capacity is smaller than the rated capacity of the battery, and the discharge rate also affects the end of the battery. Voltage value. When the battery is discharged, the electrochemical reaction current is preferentially distributed on the surface closest to the main solution, resulting in the formation of lead sulfate on the surface of the electrode to block the inside of the porous electrode. In the case of large current discharge, the above problem is more prominent, so the discharge current becomes larger, the capacity given by the battery is smaller, and the terminal voltage value decreases faster, that is, the discharge termination voltage value decreases as the discharge current increases. On the other hand, the lower the discharge rate, the better. Some studies have shown that the long-term too small discharge rate will increase significantly due to the formation of lead sulfate molecules. The stress will cause the plate to bend and the active material to fall off, which will also reduce the use of the battery. life.
3, the outside temperature is too high
The rated capacity of the battery refers to the value of the battery at 25 ° C. It is generally considered that the operating temperature of the valve-regulated sealed lead-acid battery is ideal in the range of 20~30 °C. When the battery temperature is too low, the battery capacity is reduced because the electrolyte does not react well with the active material of the plate under low temperature conditions. The capacity reduction will not meet the expected backup time and remain within the specified discharge depth, which can easily cause overdischarge of the battery. From the external parameters of the battery, the voltage has a great relationship with the temperature. For every 1 °C increase in temperature, the voltage drop of the single cell drops by 3 mV. That is to say, the voltage of the lead-acid battery has a negative temperature coefficient and its value is -3 mV/°C. By the same token, an increase in ambient temperature tends to cause overdischarge of the battery. High temperatures can also cause battery water loss and thermal runaway. Temperature is a major factor affecting the normal operation of the battery. In solar photovoltaic systems, the controller is generally required to have a temperature compensation function.
4, partial discharge
5, high temperature storage