An elementary battery charger using a 60 to 80 W incandescent lamp is shown in the figure. 1N4004 diodes were used for the 110 V network, but higher current types can also be used. Note that the current with a 60 W lamp will be in the order of 0.5 A, so there really are no need for three diodes as suggested by the author of the project. For the 220 V power grid, 1N4007 diodes must be used. When using the device, disconnect the battery completely from the car, as the circuit is not isolated from the mains and the high voltage present can damage the electronic devices of the automobile installation.
