Here’s an Instructable about a DIY charger for car’s battery with an analog DC ammeter in the front panel. A PIC12F683-based control circuit is enclosed inside which adds some intelligence to this charger. The PIC MCU checks the terminal voltage of the battery being charged in every ten minutes using one of its analog inputs, and if it is found above a set threshold, the charging process is stopped. A relay switch is included into the circuit to connect/disconnect the charger output and the battery terminals.
PIC-based battery charger