To make a homemade battery charger, a transformer needs to be combined with a fuse, rectifier and fuse holder. A wooden plate and cables that correspond with the device that is being charged may also be necessary.
The main power that the battery charger is being connected to should be connected with the primary windings that are present in the transformer. The transformer can be rated at any watt, but the most commonly recommended watt is a 50-watt transformer. The transformer should be covered up after the cables are connected to ensure nobody touches it or gets electrocuted. If the transformer does not come with a cover, it should be placed into a supplementary insulated box. Once the transformer is connected to the main power, the fuse and the fuse holder can be connected to the other end of the circuit. The rectifier will be placed in between the transformer and the fuse with the fuse remaining on the top part of the rectifier. The fuse should always be placed in a holder to ensure it remains in the same position. The entire charger can be secured to a wooden plate to allow it to stand upright.