Abstract: A circuit for supplying energy from a battery to the load of an energy-using device is provided wherein the circuit provides for notification to the operator of the device that the remaining energy of the battery is low. The notification is provided at a time when sufficient energy remains in the battery for the operator to perform certain essential tasks. The circuit includes a battery having a plurality of cells connected in series, a first portion of which have a higher deliverable energy capacity than a second portion of the plurality of cells. The circuit further provides for sensing a characteristic of the battery indication of the remaining deliverable energy capacity lower deliverable capacity cell portion and for switching the circuit from a first mode of operation wherein energy is delivered to the load from all of the cells in the plurality to a second mode of operation wherein the energy is delivered to the load from only the higher capacity portion of cells.

Abstract: A battery charger having a housing, a transformer in the housing and separate sets of external terminals situated on recessed surfaces at opposed sides of the housing, the external terminals being connected to separate secondary windings of the transformer so that the terminal sets are oppositely phased electrically. Blade connectors spaced apart along the line of spacing between opposed sides are electrically connected to the primary winding and extend through the housing for acceptance by an external electrical receptacle. A grounding pin being mechanically affixed to the transformer core structure and similarly extending through the housing.

Abstract: A battery charging system is provided including a charger and a rechargeable battery of "standard" size and configuration. The rechargeable battery bears a special indicia that is sensed by the charger as a precondition to enabling the charging circuit of the charger. The indicia-bearing battery can thus be used in place of "standard" non-rechargeable batteries in battery using products of various sorts, but non-rechargeable batteries, lacking the special indicia, cannot be charged in the charger. Potential damage to the charger or product and other adverse effects associated with charging of non-rechargeable batteries is thus avoided.

Abstract: A battery charging system is provided for charging a rechargeable batteries and for distinguishing the rechargeable battery from a non-rechargeable battery. The charging system establishes an electromagnetic field proximate the battery. A circuit within the battery enters a resonant condition in response to the electromagnetic field and the resonant condition is sensed by the charging system to switch the charging system from a non-charging mode to a charging mode.

Abstract: A battery charging system is provided which distinguishes between primary and secondary batteries by sensing a charging or discharging parameter of a battery placed into the system. A sensing means is included in the system which senses the value of at least one parameter of the battery. The parameter has a value for secondary batteries which is distinctive from its value for primary batteries. In response to an indication from the sensing means that the battery in the system is a primary battery, an enabling means disables charging of the primary battery by the system. The enabling means, in response to an indication from the sensing means that the battery in the system is a secondary battery, enables charging of the secondary battery by the system. One battery parameter which is particularly useful in discriminating between primary and secondary batteries is the low frequency impedance of the battery during charging.

Abstract: A system and circuit for charging a rechargeable battery from an external source of direct current is provided wherein the circuit includes an indicator for indicating the passage of charge current through the circuit. The circuit precludes the indicator from providing a false indication of the passage of charging current.

Abstract: Charging apparatus having visual indicating means, e.g., a light emitting diode, responsive to the delivery of charging current to rechargeable cells having different physical sizes and/or electrical charging characteristics. The apparatus includes at least two sets of terminals for connecting cells requiring different respective charging current in one of two parallel charging paths. A first charge rate path supplies part of the charging current to cells of high current demand and a second charge rate path supplies charging current to cells of low current demand.

Abstract: A charger supplies a battery of sealed electrochemical cells with fast rate charging current in a controlled manner. A controllable circuit element is connected between the charge current source and the battery. This element is caused to modulate the charge current in a manner so as to initially fast charge the sealed battery, but to limit its subsequent rise in temperature above the ambient to a predetermined small differential and to maintain that differential. This temperature rise limit brings about a reduction of charge rate as the battery approaches the full charged condition resulting in an acceptable current level for long term overcharge operation.

Abstract: An indicator of full charge for secondary sealed cells and like cells which become heated when subjected to overcharge current, or batteries of such cells, undergoing a charging operation includes a heat sensitive mechanism adapted to change a perceivable characteristic in response to the rise in temperature of the cell or battery as the charging operation continues beyond full charge. Part of the heat sensitive mechanism is thermally coupled to the battery or cell and another part is maintained at ambient temperature so that the perceivable characteristic of the portion maintained at ambient temperature and that of the portion at the raised temperature of the overcharged battery or cell can be readily observed to signify that full charge has been attained. As preferably embodied, the heat sensitive mechanism is a liquid crystal material.

Abstract: A battery charger with an indicator to indicate full charge of secondary sealed cells and like cells which become heated when subjected to overcharge current, or batteries of such cells, the indicator comprising a heat sensitive mechanism which is mounted to the charger housing and is adapted to change a perceivable characteristic in respone to the rise in temperature of the cell or battery as the charging operation continues beyond full charge. Part of the heat sensitive mechanism is thermally coupled to the battery or cell and another part is maintained at ambient temperature so that the perceivable characteristic of the portion maintained at ambient temperature and that of the portion at the raised temperature of the overcharged battery or cell can be readily observed to signify that full charge has been attained. As preferably embodied, the heat sensitive mechanism is a liquid crystal material.

Abstract: In a charger for rechargeable electrochemical cells, a transformer charging circuit supplies a charging current to the battery at a fast charge rate for a predetermined time followed by a continuous slow charge rate. A normally closed automatic reset thermostat in series with the rectifier diodes in the charging circuit, and thermally coupled to them, opens after a period of time, dependent upon the heat generated by the rectifier diodes and upon the thermal mass of the thermostat and diodes, and terminates the fast charge current. A resistor, shunted across the thermostat and thermally coupled to it, establishes a slow charge rate current path when the thermostat opens. Heat generated in the resistor causes the thermostat to remain open as long as the battery is connected and AC power is supplied to the transformer primary winding.

Abstract: A charging system for rechargeable batteries of the 9 volt type includes a charger adapted to accept a plurality of cells of different sizes and electrical characteristics and an adapter module for mechanically and electrically interconnecting the charger to a 9 volt size battery.

Abstract: A charger adapter includes a two element housing wherein each of the elements carry snap fit terminals. The elements are positioned in juxtaposition to define an internal cavity for holding current limiting circuitry. The elements may be joined by a hinge to form a unitary structure. One surface of the housing includes an alignment wall and index for aligning battery terminals with the adapter terminals.An alternative one piece housing is also described.

Abstract: A charging system for alternatively charging cells having different physical sizes and/or electrical characteristics comprising a charge current source, a plurality of cellholder modules and interconnection means on said charger and said modules for selective alternative connection of each of said modules to the charger. Each module has an electrical circuit including a discharge prevention means for preventing inadvertent discharge of cells disposed in the module.

Abstract: A controlled battery charger system is provided wherein a rechargeable battery is charged at a high charge rate and the voltage and temperature of the battery are both monitored by sensing means which are coupled to switching means to shut off the high charge-rate current when either the temperature or the voltage of the battery reaches a predetermined level.