Abstract: Systems and methods for accurate control of battery pre-charge current use external charge FET external discharge FET for accurate control of battery pre-charge current. A low Vforward diode or other component and series resistor form a parallel path around the discharge FET. It is preferable for the component to have a voltage drop significantly less than that of the parasitic diode in the FET when carrying current in one direction and substantially higher voltage drop in the other direction. During a pre-charge condition, the discharge FET is turned off, and a servo amplifier monitors the voltage across the series resistor. The servo amplifier controls the gate of the charge FET such that a desired current is flowing from the charger to the battery.

Abstract: A system interface having an interface for dual battery packs provides for power up sequencing of battery packs and pack switching under the control of a host processor within associated system electronics. The host processor communicates with each battery pack via a pack interface that includes a single wire mode control signal and a single wire status signal. The mode control signal allows the host processor to control the operational mode of selector switches within the respective battery pack. The single wire status signal provides status information to the host processor regarding the state of the selector switches within the respective battery pack. The mode and status signals are multi-state signals that permit at least three states to be identified via the single wire interface. Selector switches are provided only in the battery packs. No selector switches are included in the system electronics to minimize voltage drops between the selected battery pack and the system electronics.

Abstract: An apparatus for improving protection of a battery pack when the battery pack is in a very low power state, the battery pack including a plurality of battery cells coupled to present an output voltage at a battery potential locus and a protection device for providing a plurality of safeguards to protect the battery pack, affects operation of the protection device to control at least one safeguard and includes a current sensing unit coupled with the plurality of battery cells and with the protection device. The current sensing unit senses a battery traversing current associated with at least one battery cell. The current sensing unit generates an alerting signal when the battery traversing current exceeds a predetermined value. The protection device enables the at least one safeguard in response to the alerting signal.

Abstract: An apparatus for use with a charge control system for affecting current draw from a charging unit coupled at an input locus of the charge control system for charging a battery unit includes a current sink switchingly coupled with the input locus for selectively contributing a predetermined current draw at the input locus. A method for selectively establishing a predetermined current draw from a charging unit coupled at an input locus with a charge control unit for charging a battery unit includes the steps of: (a) providing a current sink switchingly coupled with the input locus; (b) sensing at least one predetermined condition in the battery unit; and (c) switchingly engaging the current sink when the at least one predetermined condition satisfies at least one predetermined criteria.

Abstract: A method for controlling voltage levels among cells while charging a battery array to a target voltage uses cell balancing modes employing respective charging currents. The method includes the steps of: (a) In no particular order: (1) establishing a parametric criterion for identifying each balancing mode; (2) identifying a performance parameter associated with selected cells for each balancing mode; and (3) establishing an exit criterion for each balancing mode; (b) ascertaining the onset of charging; (c) identifying the extant balancing mode; (d) employing the charging current for the extant balancing mode for charging; (e) for selected cells: (1) obtaining an extant parameter associated with the cell; (2) comparing each extant parameter with the exit criterion; and (3) repeating steps (e)(1) through (e)(2) until the extant parameter satisfies the exit criterion; (f) terminating the extant balancing mode; (g) repeating steps (c) through (f) until target voltage is achieved; (h) terminating charging.

Abstract: A method for controlling voltage levels among cells while charging a battery array to a target voltage uses cell balancing modes employing respective charging currents. The method includes the steps of: (a) In no particular order: (1) establishing a parametric criterion for identifying each balancing mode; (2) identifying a performance parameter associated with selected cells for each balancing mode; and (3) establishing an exit criterion for each balancing mode; (b) ascertaining the onset of charging; (c) identifying the extant balancing mode; (d) employing the charging current for the extant balancing mode for charging; (e) for selected cells: (1) obtaining an extant parameter associated with the cell; (2) comparing each extant parameter with the exit criterion; and (3) repeating steps (e)(1) through (e)(2) until the extant parameter satisfies the exit criterion; (f) terminating the extant balancing mode; (g) repeating steps (c) through (f) until target voltage is achieved; (h) terminating charging.

Abstract: An apparatus for use with a charge control system for affecting current draw from a charging unit coupled at an input locus of the charge control system for charging a battery unit includes a current sink switchingly coupled with the input locus for selectively contributing a predetermined current draw at the input locus. A method for selectively establishing a predetermined current draw from a charging unit coupled at an input locus with a charge control unit for charging a battery unit includes the steps of: (a) providing a current sink switchingly coupled with the input locus; (b) sensing at least one predetermined condition in the battery unit; and (c) switchingly engaging the current sink when the at least one predetermined condition satisfies at least one predetermined criteria.