How to judge an unbalanced battery?

This is the easiest way to distinguish. Lithium batteries generally have a long charging and discharging life, for example, they can maintain 75% of their capacity after 1000 cycles of charging and discharging. If the new car has not been used for a long time and the number of recharges is not many, it feels that the battery life is not as good as in the past, then it is likely to be unbalanced. The more the battery life drops, the more likely it is that the battery is not balanced. Of course, this kind of judgment method should pay attention to the influence of other conditions. For example, uphill and mountain climbing are very battery-intensive, and vigorous sports will also consume more power. In winter, the battery capacity is inherently reduced in cold weather. 2. The charging time becomes shorter. It takes about 2 hours to turn the green light. If the time to turn the light is earlier, it means that the charged power is low, and it is probably not balanced. Severely unbalanced, there will be a phenomenon that the battery will run out after a while and the charge will be full after a while. The charging experiment should also exclude the influence of some special factors. For example, if you just get it indoors in winter, you have to wait for one or two hours before the battery temperature rises before charging. In addition, the battery is not fully discharged, including no electricity for outdoor riding in winter, and a lot of electricity can be discharged indoors. At this time, the charging will naturally overflow for a short time. 3. See the battery discharge curve in front to see the change in power status when using it. For a normal battery, the power is average and gradually decreased during riding. If the battery is unbalanced, it will drop quickly in the second half. For example, T260, it is reasonable to say that the flashing light states that 1/3 of the power is used, and 2/3 is used for fast flashing, and 1/3 is left. However, if there is no power soon after the fast flashing, it will even be out of power shortly after the slow flashing. It shows that there is serious imbalance. Similarly, if the battery is displayed in 4 grids, if the battery is out of power soon after reaching 2 grids, it means that it has been unbalanced. The reason for this judgment method is that the power display is calculated based on the total voltage, and the total voltage generally does not drop much when it is unbalanced, but individual batteries will quickly lose power and cause the protection board to protect. 4. Use the method of observing the charging current to judge whether it is normal after the charger turns to the green light during equalizing charging. If there is still a charging current (about 0.2A) and gradually decreases, then it is normal. If the charging current suddenly decreases to 0 when the red light turns to green, it means that there is an imbalance. At this time, the charging circuit is over-voltage protected because the voltage of a certain battery reaches 4.25V. Under normal circumstances, the voltage of the charger will be evenly divided by the battery, for example, 67.2V divided by 16 is 4.2V. However, if the unbalance occurs, the voltage of some batteries is low, which will inevitably cause some batteries to exceed 4.2V. When it exceeds 4.25V, the charging protection will be triggered and the charging current will be completely cut off. You can use a DC clamp meter to measure the charging current. Digital clamp meters with a range of 2A/4A/20A/40A can be used. Note that some clamp meters only have an AC range, which cannot be used. Peel off the outer skin of the charger wire (be careful not to damage the outer skin of the inner core wire), separate a strand for the clamp meter to insert and then measure: (The above clamp meter is Fluke319, with 40A DC current range, full scale 40.00A, distinguish 0.01A. Its practical domestic UNI-T UT210E is good, with a DC current of 2.000A, distinguishing 1mA) 5. Observe the charging voltage to determine whether it is unbalanced and normal charging. When the red light turns to green, it still has charging. In the presence of current and internal resistance, the output voltage of the charger cannot reach 67V. If during charging, the voltage suddenly rises when the red light turns to green, for example, it jumps from 66.5V to 67.15V at once, and this 67.1V is the no-load voltage when the unicycle charging plug is unplugged, which means that there is no charging current. , The charging is protected and unbalanced. The lower the voltage before the jump, the more serious the imbalance. If you have the conditions, you can collect the charging voltage data and make the charging voltage curve, which is clear at a glance (see the following example). For voltage measurement, you can peel off the outer skin of the charging cable, stagger and then peel off the inner core, and collect the voltage signal with a hook or clip: After the voltage measurement is completed, it should be wrapped with tape. 6. Temperature judgment method After the battery is overflowing and the charger turns green, continue charging for more than 2 hours, and then touch the side of the wheelbarrow battery. If there is warmth, it means that the battery balance protection board is working, and the battery is declared balanced at this time . If the battery side of the unicycle does not heat up, it means that the overvoltage protection is caused by the imbalance. Of course, it may also be a low-quality wheelbarrow without a balanced protection plate, so that there is no temperature and it is impossible to tell whether it is balanced (if there is temperature, it is balanced). 7. Internal inspection method such as T260 overflowing electricity first, then disassemble the side guard plate with switch, unplug the power cord and voltage monitoring socket, measure the voltage of the single battery on the two voltage test sockets one by one, and get the battery straight Is it balanced data? If the difference between the lowest voltage and the highest voltage is 0.2V, it is equivalent to a 20% difference in capacity, which is not evenly balanced. The greater the difference, the greater the unevenness. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous post: Analysis of the reason for the failure of the lithium battery