Abstract: An electrical combination. The electrical combination comprises a battery pack configured to be interfaced with a hand held power tool, a control component, and a semiconducting switch. The transfer of power from the battery pack to the hand held power tool is controlled by the control component and the switch based on one of a battery pack state of charge and a respective state of charge of one of a plurality of battery cells. A discharge current of the battery pack is regulated based on the switch being controlled into one of a first state and a second state by the control component to selectively enable the transfer power from the plurality of battery cells to the hand held power tool.

Abstract: An electrical combination including a power tool and a battery pack. The power tool includes power tool terminals. The battery pack is configured to be interfaced with the power tool. The battery pack includes a battery pack housing, at least three terminals, and a plurality of battery cells. The battery pack terminals include a positive terminal, a negative terminal, and a sense terminal. The at least three terminals are configured to be interfaced with the power tool terminals. The plurality of battery cells are arranged within and supported by the battery pack housing. Each of the battery cells has a lithium-based chemistry and a respective state of charge, and power is transferable between the battery cells and the power tool. A circuit is configured to monitor the battery cells, detect a charge imbalance among the battery cells, and prevent the battery pack from operating when the charge imbalance is detected.

Abstract: A method and system for charging multi-cell lithium-based batteries. In some aspects, a battery charger includes a housing, at least one terminal to electrically connect to a battery pack supported by the housing, and a controller operable to provide a charging current to the battery pack through the at least one terminal. The battery pack includes a plurality of lithium-based battery cells, with each battery cell of the plurality of battery cells having an individual state of charge. The controller is operable to control the charging current being supplied to the battery pack at least in part based on the individual state of charge of at least one battery cell.

Abstract: A fail safe battery pack is disclosed and claimed wherein first and second housings are affixed together. A plurality of battery cells reside within and fixedly engage the first and the second housings. First and second printed circuit boards (PCBs) reside within first and second lattice structures of the first and second housings. A variable bias device resides in the first and/or second lattice structure of the first and second housing and engages the first and/or second PCBs. When the bias of the variable bias device is sufficiently large it overcomes a plurality of fixed mechanically biased devices operating between the PCB and the plurality of battery cells and tending to separate same and causes the PCB to electrically communicate with the plurality of battery cells. When the bias of the variable bias device is sufficiently small, the plurality of fixed mechanically biased devices separates the PCB and the plurality of battery cells rendering the battery cells in an electrically safe condition.

Abstract: An In-Building Communications system is disclosed which permits communication in tunnels, underground parking garages, tall buildings such as skyscrapers, buildings having thick walls of concrete or metal, and/or any building which has communication dead zones due to electromagnetic shielding. The invention includes a portable bi-directional amplifier (BDA) system, an outdoor antenna system attached to the building or independently mountable, an indoor antenna system attached to the building or independently mountable inside the building, and a standardized, In-Building Communications (IBC) interface box affixed preferably to the exterior of the building. The interface box communicates with antenna systems attached to the building.

Abstract: An electrical combination. The electrical combination comprises a battery pack configured to be interfaced with a hand held power tool, a control component, and a semiconducting switch. The transfer of power from the battery pack to the hand held power tool is controlled by the control component and the switch based on one of a battery pack state of charge and a respective state of charge of one of a plurality of battery cells. A discharge current of the battery pack is regulated based on the switch being controlled into one of a first state and a second state by the control component to selectively enable the transfer power from the plurality of battery cells to the hand held power tool.

Abstract: A method for conducting an operation including a power tool battery pack. The battery pack can include a housing, a first cell supported by the housing and having a voltage, and a second cell supported by the housing and having a voltage. The battery pack also can be connectable to a power tool and be operable to supply power to operate the power tool. The method can include discharging one of the first cell and the second cell until the voltage of the one of the first cell and the second cell is substantially equal to the voltage of the other of the first cell and the second cell.

Abstract: A method and system for charging multi-cell lithium-based batteries. In some aspects, a battery charger includes a housing, at least one terminal to electrically connect to a battery pack supported by the housing, and a controller operable to provide a charging current to the battery pack through the at least one terminal. The battery pack includes a plurality of lithium-based battery cells, with each battery cell of the plurality of battery cells having an individual state of charge. The controller is operable to control the charging current being supplied to the battery pack at least in part based on the individual state of charge of at least one battery cell.

Abstract: An In-Building Communications system is disclosed which permits communication in tunnels, underground parking garages, tall buildings such as skyscrapers, buildings having thick walls of concrete or metal, and/or any building which has communication dead zones due to electromagnetic shielding. The invention includes a portable bi-directional amplifier (BDA) system, an outdoor antenna system attached to the building or independently mountable an indoor antenna system attached to the building or independently mountable inside the building, and a standardized, In-Building Communications (IBC) interface box affixed preferably to the exterior of the building. The interface box communicates with antenna systems attached to the building.

Abstract: An electrical combination. The combination comprises a hand held power tool, a battery pack and a controller. The battery pack includes a battery pack housing connectable to and supportable by the hand held power tool, a plurality of battery cells supported by the battery pack housing, each of the plurality of battery cells having a lithium-based chemistry, being individually tapped and having an individual state of charge. A communication path is provided by a battery pack sense terminal and a power tool sense terminal. The controller is operable to monitor a state of charge of a number of battery cells less than the plurality of battery cells and to generate a signal based on the monitored state of charge of the number of battery cells less than the plurality of battery cells, the signal being operable to control the operation of the hand held power tool.

Abstract: An electrical combination including a power tool and a battery pack. The power tool includes power tool terminals. The battery pack is configured to be interfaced with the power tool. The battery pack includes a battery pack housing, at least three terminals, and a plurality of battery cells. The battery pack terminals include a positive terminal, a negative terminal, and a sense terminal. The at least three terminals are configured to be interfaced with the power tool terminals. The plurality of battery cells are arranged within and supported by the battery pack housing. Each of the battery cells has a lithium-based chemistry and a respective state of charge, and power is transferable between the battery cells and the power tool. A circuit is configured to monitor the battery cells, detect a charge imbalance among the battery cells, and prevent the battery pack from operating when the charge imbalance is detected.

Abstract: A method for conducting an operation including a power tool battery pack. The battery pack can include a housing, a first cell supported by the housing and having a voltage, and a second cell supported by the housing and having a voltage. The battery pack also can be connectable to a power tool and be operable to supply power to operate the power tool. The method can include discharging one of the first cell and the second cell until the voltage of the one of the first cell and the second cell is substantially equal to the voltage of the other of the first cell and the second cell.

Abstract: An In-Building Communications system is disclosed which permits communication in tunnels, underground parking garages, tall buildings such as skyscrapers, buildings having thick walls of concrete or metal, and/or any building which has communication dead zones due to electromagnetic shielding. The invention includes a portable bi-directional amplifier (BDA) system, an outdoor antenna system attached to the building or independently mountable, an indoor antenna system attached to the building or independently mountable inside the building, and a standardized, In-Building Communications (IBC) interface box affixed preferably to the exterior of the building. The interface box communicates with antenna systems attached to the building.

Abstract: Systems and methods for calculating gas densities within a fluid enclosure are disclosed. In an example embodiment, a system includes a temperature probe for measuring an enclosure temperature in a fluid enclosure filled at least in part with a fill gas, an atmospheric pressure sensor for measuring the atmospheric pressure outside the fluid enclosure, a gas sensor for measuring an enclosure pressure within the fluid enclosure, and a controller for calculating a fill gas density within the fluid enclosure based at least in part on the enclosure temperature, the atmospheric pressure, the enclosure pressure, and a gas coefficient of the fill gas.

Abstract: A method and system for charging multi-cell lithium-based batteries. In some aspects, a battery charger includes a housing, at least one terminal to electrically connect to a battery pack supported by the housing, and a controller operable to provide a charging current to the battery pack through the at least one terminal. The battery pack includes a plurality of lithium-based battery cells, with each battery cell of the plurality of battery cells having an individual state of charge. The controller is operable to control the charging current being supplied to the battery pack at least in part based on the individual state of charge of at least one battery cell.

Abstract: An electrical combination. The combination comprises a hand held power tool, a battery pack and a controller. The battery pack includes a battery pack housing connectable to and supportable by the hand held power tool, a plurality of battery cells supported by the battery pack housing, each of the plurality of battery cells having a lithium-based chemistry, being individually tapped and having an individual state of charge. A communication path is provided by a battery pack sense terminal and a power tool sense terminal. The controller is operable to monitor a state of charge of a number of battery cells less than the plurality of battery cells and to generate a signal based on the monitored state of charge of the number of battery cells less than the plurality of battery cells, the signal being operable to control the operation of the hand held power tool.

Abstract: An electrical combination including a power tool and a battery pack. The power tool includes power tool terminals. The battery pack is configured to be interfaced with the power tool. The battery pack includes a battery pack housing, at least three terminals, and a plurality of battery cells. The battery pack terminals include a positive terminal, a negative terminal, and a sense terminal. The at least three terminals are configured to be interfaced with the power tool terminals. The plurality of battery cells are arranged within and supported by the battery pack housing. Each of the battery cells has a lithium-based chemistry and a respective state of charge, and power is transferable between the battery cells and the power tool. A circuit is configured to monitor the battery cells, detect a charge imbalance among the battery cells, and prevent the battery pack from operating when the charge imbalance is detected.

Abstract: An In-Building Communications system is disclosed which permits communication in tunnels, underground parking garages, tall buildings such as skyscrapers, buildings having thick walls of concrete or metal, and/or any building which has communication dead zones due to electromagnetic shielding. The invention includes a portable bi-directional amplifier (BDA) system, an outdoor antenna system attached to the building or independently mountable, an indoor antenna system attached to the building or independently mountable inside the building, and a standardized, In-Building Communications (IBC) interface box affixed preferably to the exterior of the building. The interface box communicates with antenna systems attached to the building.

Abstract: An electrical combination. The electrical combination comprises a battery pack configured to be interfaced with a hand held power tool, a control component, and a semiconducting switch. The transfer of power from the battery pack to the hand held power tool is controlled by the control component and the switch based on one of a battery pack state of charge and a respective state of charge of one of a plurality of battery cells. A discharge current of the battery pack is regulated based on the switch being controlled into one of a first state and a second state by the control component to selectively enable the transfer power from the plurality of battery cells to the hand held power tool.

Abstract: A method for conducting an operation including a power tool battery pack. The battery pack can include a housing, a first cell supported by the housing and having a voltage, and a second cell supported by the housing and having a voltage. The battery pack also can be connectable to a power tool and be operable to supply power to operate the power tool. The method can include discharging one of the first cell and the second cell until the voltage of the one of the first cell and the second cell is substantially equal to the voltage of the other of the first cell and the second cell.