Abstract: An electrical device for use with electric storage batteries has a bi-level battery state-of-charge indicator incorporated therein. The electrical device is shown as a battery cable connector and a battery cable clamp. The built-in indicator provides an indication of the battery state-of-charge when the battery reads a preselected state-of-charge and continues to provide such an indication until the battery has been discharged to a preselected state. The indicator utilizes a light emitting diode to monitor the battery state-of-charge through the use of bi-level voltage comparator circuit.

Abstract: An electrical device for use with electric storage batteries has a bi-level battery state-of-charge indicator incorporated therein. The electrical device is shown as a battery cable connector and a battery cable clamp. The built-in indicator provides an indication of the battery state-of-charge when the battery reads a preselected state-of-charge and continues to provide such an indication until the battery has been discharged to a preselected state. The indicator utilizes a light emitting diode to monitor the battery state-of-charge through the use of bi-level voltage comparator circuit.

Abstract: A method and apparatus for determining the capacity of lead acid storage batteries are disclosed. The battery's initial open circuit voltage is stored in a settable memory. Thereafter, the open circuit voltage values of the battery throughout the discharge period are determined by measuring loaded voltages with reference to the stored open circuit voltages to detect the discharge rates. The rates of discharge are used to reset the stored value of the initial open circuit voltage measurement thereby producing a moving reference. The memory output value is a function of the capacity of the battery. During the charge period, the charge voltages are measured with reference to the stored open circuit voltages to detect the charge rates. The rates of charge are used to reset the stored value of an initial open circuit voltage measurement. Again, the memory output value is a function of the capacity of the battery.

Abstract: A switchable electrical connector for use in explosion prone environments is disclosed. The connector utilizes two pairs of electrical connectors; the first pair provides a circuit switching function while the second pair permits the removable connection of a suitable load. Sealing means are used for the first pair of electrical connectors to isolate any switching arcs from the environment. A mechanically actuated interlock is employed to prevent electrical engagement of the first pair of connectors before engagement of the second pair of connectors and to prevent disengagement of the second pair of connectors before the disengagement of the first pair of connectors.