AUTOMATIC BATTERY CHARGING CIRCUIT OPERABLE OVER A WIDE TEMPERATURE RANGE

An automatic battery charging and voltage regulating system for connection between a source of voltage and a battery to be charged which battery may have current consuming equipment connected thereto and may have a thermistor attached thereon whose resistance varies in accordance with battery temperature. The system includes a converter coupled to the source of voltage which develops a charging voltage for charging the battery, a current control circuit is coupled to the converter and to the battery and operates to limit the maximum charging current to the battery to a first level if there is no thermistor or if the thermistor resistance exceeds a predetermined amount, and to the second level, if the thermistor resistance is below the predetermined amount. A voltage sensing circuit is also provided which senses the battery voltage in excess of a predetermined level and reduces the charging voltage developed by the converter.