Because some "power grids" have been internally short-circuited, the evidence is: ~ the power failure is very fast, almost plummeting.

What's worse is to replace the battery where individual bad batteries are located, so that the whole battery will be unbalanced, and some new batteries will accelerate the death!

Effective solution: update the whole group!

In recent years, the original brands "Ultramicro" and "Tianneng" also have battery products that cut corners. Its design life is only 1 year (above), so your battery has reached the "normal life"!