The 5207442 is a charging and maintenance device for 1-6 micro AAA/Mignon AA, 1-4 Baby C/Mono D and 1-2 9V E-Block rechargeable batteries. After inserting the batteries, the charger starts an automatic diagnosis and a quick capacity test for about five seconds. Depending on the condition of the battery, the device selects a gentle pre-charge and/or refresh program, or initiates the actual charging process. The refresh mode restores performance of rechargeable batteries damaged by storage or memory effect, and prolongs their life cycle considerably. Once a battery is fully charged, the charging process is automatically stopped and switched to trickle charging (buffer charging with current impulses). This feature ensures optimum performance and counteracts the self-discharge of the battery. The battery can thus remain in the device until it is used. A clearly arranged LED display shows the current program mode for each charging slot separately. Should a non-rechargeable or defective battery be inserted accidentally, this will be indicated by a flashing red LED.