How do I know when my battery’s service life has ended?

The occurrence of the symptoms below could indicate that your rechargeable batteries need replacing. 

• The battery has been used extensively over the last few years and its operating time has started to decrease after charging. As a guideline, if the operating time is cut in half, it is time to replace your rechargeable batteries.
• If the charging of one battery poses a lot of difficulties e.g. when the charging time becomes increasingly longer. If it takes double the amount of time to charge a battery compared to other batteries of the same type, it is recommended to replace that particular rechargeable battery. 

In the cases above, if a dead battery has to be replaced in an appliance, it’s best to replace all batteries in the used appliance to negate the possibility of overcharging the other batteries. However, in the case of the defects below, the main cause could be an intermittent contact between battery and terminal. 

• Battery charge is never completed or takes a large amount of time (guideline: 2 to 3 times longer than normal charging time).
• When the operating time is noticeably short despite having used the battery only a few times.

In the cases above, it is recommended to clean the plus and minus terminals of the batteries, and the terminals of the charger with a cleaning cloth.