Regarding the problem of power tool batteries not being able to charge, the following are some possible reasons and their corresponding solutions:

1. Battery over-discharge:

If the power tool is not used for a long time, the battery power will naturally be exhausted, which may cause the battery voltage to be too low, exceeding the minimum charging voltage range of the charger, and thus unable to charge normally.
Solution: Try to use a charger with a slightly lower voltage for charging. For example, for a 60-volt 20ah electric wrench, you can try to use a 48-volt 20ah charger for charging.

2. Charger failure:

The charger itself may have problems, such as internal circuit damage, loose plug, abnormal output voltage, etc., which cannot provide the battery with a suitable charging voltage and current.
Solution: Check whether the charger plug is loose. If it is loose, plug it in tightly; if the internal circuit of the charger is damaged, it is recommended to contact a professional maintenance personnel for repair or replace a new charger.

3. Battery aging:

After multiple charge and discharge cycles, the chemical substances inside the battery will gradually deplete, and the electrode material may be damaged or passivated, resulting in a decrease in battery capacity, poor charging performance, or even failure to charge.
Solution: Try to activate the battery, for example, remove the battery from the power tool, short-circuit the positive and negative poles of the battery with a wire for a few seconds, and then connect the charger to charge. However, this method needs to be operated with caution to avoid damaging the battery due to long short-circuit time.

4. Temperature influence:

Extreme temperature conditions, whether too high or too low, may affect the charging performance of the battery. In a low temperature environment, the chemical reaction rate inside the battery slows down and the charging efficiency decreases; in a high temperature environment, the battery may have overheat protection and stop charging.
Solution: Try to charge the battery within the appropriate temperature range. Generally speaking, the best charging temperature for lithium batteries is between 0℃-45℃. If the ambient temperature is too low, you can put the battery in a warm place for a while and charge it after the temperature rises; if the temperature is too high, you should wait for the battery to cool down before charging.
With the above methods, you should be able to solve the problem of power tool battery not charging. If you encounter difficulties during implementation, please feel free to seek professional help.