If a battery has a service life that is less than 12 months, the problem is usually caused by a dead cell, that is, one of the cells has a density value that is much lower than the others. The affected cell bubbles visibly during the high-discharge test. To evaluate the density, a high-discharge test should be carried out. In some cases, the dead cell may be visible in the form of a sulphated cell.
1. In one battery assembly, voltage of other batteries is normal; only one simple grid is 2V smaller, (for example, voltage of 12V batteries is 10-10.8V, 6V batteries voltage is 4.-4.3V, and 2V batteries 0V).
2. After balanced charging, voltage of simple grid still can not meet rated voltage of 2V (12V batteries could not reach 12V above, 6V batteries could not meet 6V above, and 2V batteries could not reach 2V above), and one simple grid short-circuited heats up severely.
Possible Reason or Cause
1. Twisted poles make clapboard break.
2. Lead shot falls into batteries.
3. Broken clapboard.
4. Conductive substances fall into batteries due to inappropriate usage.
5. After long-term usage, batteries nearly use up its service life; active materials of pole plate fall off severely.
Reason(1.2.3)Inferior manufacturing, product returnable.
Reason(4.5)Inappropriate usage of user.