How the battery positive and negative should be judged?

This paper introduces several simple methods to correctly identify the positive and negative electrodes of old storage batteries for everyone to make a quick judgment when charging or testing.

1. Judging according to the design characteristics of the battery electrode

Commonly used storage batteries are in production design. The thicker end of the battery post is the positive electrode. The other end is a thinner electrode, and the color of the battery post is recognized. The positive electrode post is dark brown and the negative electrode is dark gray. In addition, the positive and negative marks of some batteries are indicated by English letters, that is, P is a positive electrode, and N is a negative electrode, so it is impossible to make mistakes during maintenance charging.

2. Using a multimeter voltage block measurement

The multimeter can be dialed to the DC gear, and the two test leads are respectively connected to the two electrodes of the battery. At this time, if the battery shows a normal voltage value, it is proved that the electrode touched by the red test pen is the positive electrode of the battery. The black pen is the negative electrode. Sometimes it is measured that the battery has no normal voltage, then the battery's weak micro-storage can be measured to determine. When the two pens touch the battery electrode, if the hands are slightly shaken to the right, the red pen is the positive electrode of the battery. The black pen is a negative electrode. However, if the pointer of the multimeter is shaken to the left (the hands are reversed), it is proved that the red pen touches the negative electrode of the battery.

3. Identification by wire short circuit

Connect the two copper core power cables to the old battery electrodes to be measured, and then pour the normally configured electrolyte (concentrated brine) into a glass cup, insert the two ends of the power cord into the tea cup, and Each of them is placed on the edge of both sides of the glass (the two lines can not touch each other in the cup), and then observe the bubbling of the respective lead ends in the electrolyte, if the blister on the bubble at the end of a certain wire is obvious and Many times. It means that one end of the power cord connected to the battery is a negative electrode, and the bubble is small and the non-obvious end is the positive electrode of the battery.

4. Using a rectifier diode

The rectifier diode in the power regulator has a unidirectional conductivity to find a rectifier diode a 40w incandescent lamp. Then, according to one pile of the battery → diode + end → diode - end → incandescent lamp → the other column of the battery is connected in series to form a series circuit of electric lamps. At this time, if the incandescent lamp in the circuit is ignited and illuminated, it is proved The diode terminal is connected to the battery post as the positive electrode of the battery and the other end is the negative electrode of the battery.

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