This research work was based on the construction of a 9V battery charger. During the testing of the battery, some of the components explode due to wrong connection and bridging of wires and this resulted to damage of the affected components. However, the damaged components were all replaced with new ones and reconnected in the rightful ways. Furthermore, in testing of this battery charger, different microphone batteries and cor were used. When testing with the microphone battery, it was discovered that the battery didn’t charge we tried as much as possible to know the possible reason behind the situation; we later discovered that there was no current supply. Hence, this situation prompted us to install LED in order to know when current has passed through the transformer. In addition, the battery charger was also tested using car battery, machine battery and generator battery. However, the charger was unable to power charge batteries whose capacities were more than 12V e.g 24V, 40V etc. After the changing of all damaged components that were used for construction of the battery charger, the result proves reliable and efficient, the battery charger was able to charge microphone batteries and any other batteries that fall within the charger’s capacity .It is therefore recommended that the government should encourage and provide enabling environment that can arouse the interest of electronic appliance construction and further studies in this field should be carried out for proper understanding.