When the engine is started, the battery continuously supplies a strong current (about 200-600 A) to the starter in a short time (5-18 s) while protecting the ignition circuit. When the engine runs at a low speed, the generator voltage is low Or not generating electricity, the battery from the battery to the car electrical equipment. Battery is equivalent to a large capacitor, can play a role in stabilizing the circuit voltage, and can be generated at any time generator over-voltage absorption, protection of electronic components are not damaged. How is the battery state of technology to judge? 1. The use of electrolyte density to determine the degree of battery discharge Electrolyte density in the charging process becomes higher, and gradually decreased in the discharge process, the electrolyte density is proportional to the degree of discharge of the battery changes, the greater the degree of battery discharge, the relative density of the electrolyte drops more. Therefore, by measuring the electrolyte density can determine the degree of charge and discharge of the battery. Under normal circumstances, the battery from sufficient to the end of the discharge, the electrolyte density decreased about 0. 16 g / cm3 so when the electrolyte density decreased 0. 01 g / cm3, equivalent to 6% of discharge, the use of this value Can make a rough estimate. It should be noted that the measured electrolyte density here is the standard temperature of 20 â„ƒ, usually measured relative density, temperature correction must be carried out, the electrolyte temperature above the standard temperature 1 â„ƒ, should be added to 000 7 of the error, each lower than the standard temperature of 1 â„ƒ, should subtract 0.0007 error. Determine the electrolyte density with a suction densitometer, as shown. The specific method is: first densitometer nozzle into a single cell, squeeze the rubber ball by hand, and then slowly release, the electrolyte will be sucked into the suction glass tube. Inhaled electrolyte should be able to float the density meter can not withstand the buoyancy is appropriate. Float float should be floated in the glass tube to avoid contact between the two, and make the density meter electrolyte level and density meter alignment and line of sight, the level of the float where the scale is the density of the electrolyte value . 2. Measuring the voltage under the load to determine the degree of discharge of the battery Electrolyte density can only explain the degree of charge and discharge of the battery, but can not explain the battery without failure and the ability to supply power to the starter. For example, the same electrolyte density reflects the degree of charge, which may be a normal result of use, or may be due to self-discharge or other failures. In general, the basic characteristics of the battery state of technology is large capacity, small internal resistance. When the technical condition of the battery becomes worse, in its discharge, especially in the large current discharge, the terminal voltage will be abnormally dropped and unstable due to the obvious increase of the pressure drop. Therefore, the battery is usually used in the case of large current (100 ~ 150 A) to measure the voltage of the terminal voltage to determine the technical conditions of the battery. There are several commonly used methods: (1) Battery with good technical condition in general shall have a cell voltage of 1.5 V or more and be stable for 5 s when tested with a high-rate discharge meter, and the cell voltage shall not differ by 0 in the check of electrolyte density. 1 V; voltage slightly lower than 1.5 V, but within 5 s still stable, belongs to the discharge too much, should be promptly charged; if the voltage drops rapidly within 5 s, it means there is fault; if the single cell without voltage indication , Then there is a serious internal short circuit, open circuit or serious failure of vulcanization. With a high rate of discharge meter should not be measuring the battery is being charged and just charged, should be stopped after a charge measurement, to prevent the measurement of poor contacts sparkle, ignite the battery of hydrogen, oxygen, A deflagration will damage the battery and cause personal injury. (2) In the car through the starter discharge to determine the degree of discharge of the battery. In the normal operating temperature of the engine, a voltage meter connected to the battery between the positive and negative, pull the distributor cover the central high voltage line and ground, start the engine continuous operation 15 s, timely observation of the voltmeter readings. With a good starter and line connection, if the voltmeter reading is greater than or equal to 9.6 V for a 12 V battery, the battery is in good technical condition; if the voltage is less than 9.6 V, the technical condition is not good. (3) through the light to determine the technical state of the battery. Turn on the starter when the headlamp is turned on at night, and judge the technical condition of the battery by the amount of darkening of the light. If the starter turn very fast, although the light a little darker, but there is still enough brightness, then the battery can maintain a certain voltage, good technical condition and charge enough; if the starter is weak, the light is very dim, then Description battery discharge too much, must be immediately charged; if the starter is turned on, the lights turn red, and quickly extinguished, then the battery discharge has exceeded the allowable limit or has been severely cured.