| Maintenance methods of 12V lithium battery protection board |
| Date：2020-12-01 Hits：422 |
| A 12V lithium battery is a battery pack with a voltage close to 12V, which is connected by multiple 3.7V lithium batteries in series. We must use a 12V lithium battery protection board to protect the series lithium battery pack. When the lithium battery is fully charged, it can play the role of equalizing the voltage difference of each single lithium battery, and effectively deal with the loopholes in the series circuit. However, when the 12V lithium battery pack protection board appears abnormal, how to repair it? Next, some common problems of protection board are listed and analyzed for maintenance. 1、 No voltage or abnormal voltage If there is no voltage or abnormal voltage, set the multimeter to DC 20V gear, and then use the red meter pen to contact the positive pole of 12V lithium battery cell, and the black pen to contact the negative pole of battery cell. If the multimeter shows no voltage or low voltage, the battery cell has been damaged. Pay attention to check whether the positive and negative electrodes of the protection board are connected in reverse. If it is reversed, the charger will charge the 12V lithium battery pack with forced over discharge. 2、 There is no over-current protection If there is no over-current protection and other conditions, first of all, check whether the over-current circuit is abnormal, if some, replace the protection IC 3、 No or excessive resistance It is necessary to find out the cause from the identification circuit of the resistance pad to see whether the identification resistance is desoldered, pasted with wrong resistance, short circuit or open circuit. 4、 No electricity Use the multimeter switch to select 20V gear, and then use the red electric meter pen to contact the positive pole of the cell or the protection board. If the multimeter shows voltage, we should analyze it according to the following conditions: whether there is output voltage and whether the cell voltage is normal. If the above voltage is not normal, we can basically judge that the protection IC or MOS tube has been damaged, as long as the two components can be replaced. 5、 No or excessive internal resistance 1. If there is no internal resistance, you need to check whether the MOS transistor pin is damaged, and if there is, just replace the MOS transistor. 2. If the internal resistance is too large, it is necessary to use the probe to contact the 12V lithium battery protection plate to check whether there is contact with poor quality or excessive oxidation and other reasons. It is also necessary to check whether there are more nickel plates on the cell. If the number of nickel plates on the cell is too large, the internal resistance will be too large. The maintenance methods of 12V lithium battery protection plate used above are basically through comparison, visual inspection, voltage measurement and normal turn-off test. As long as you understand these means, you can overhaul the protection board of 12V lithium battery pack. |
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