BATTERY MANAGEMENT SYSTEM

1 .- 10 . (canceled)

11 . A battery management system for a rechargeable battery, comprising:

a controller;

at least one sensor for providing a sensor signal relating to at least one parameter of the rechargeable battery to the controller; and

a data store;

wherein the controller is configured to:

compare the sensor signal to a threshold condition; and

determine whether to write data to the data store based on the comparison with the threshold condition.

12 . The battery management system of claim 11 wherein comparing the sensor signal to a threshold condition comprises reading a reference from a memory, and comparing the sensor signal to the reference.

13 . The battery management system of claim 11 wherein the at least one sensor comprises a plurality of sensors, each sensor configured to provide a corresponding sensor signal, and wherein the controller is configured so that, in response to the controller determining to write data to the data store based on the comparison with the threshold condition, the controller writes data relating to the plurality of parameters to the data store.

14 . The battery management system of claim 11 wherein a previously written value of the at least one parameter provides the threshold condition.

15 . The battery management system of claim 11 wherein writing data to the data store comprises overwriting a previous value of the at least one parameter that may be stored in the data store.

16 . The battery management system of claim 11 wherein the threshold condition comprises a state of charge of the battery falling below a threshold.

17 . The battery management system of claim 11 wherein the controller is configured to select a threshold condition depending on at least one of (i) whether the rechargeable battery pack is being charged, (ii) whether the rechargeable battery pack is being discharged and (iii) whether the rechargeable battery pack is being stored.

18 .- 20 . (canceled)

21 . The battery management system of claim 11 wherein, in response to the at least one sensor signal reaching and/or exceeding a first threshold condition, the controller is configured to power down a first set of components of the battery management system, and in response to the signals indicative of at least one of the at least one parameters reaching and/or exceeding a second threshold condition, the controller is configured to power down a second set of components of the battery management system.

22 . A battery management system for a rechargeable battery, comprising a sensor for providing a sensor signal relating to a parameter of the rechargeable battery to the controller, wherein in response to the sensor signal meeting a first condition, the battery management system is configured to power down a first set of components, and in response to the sensor signal meeting a second condition, the battery management system is configured to power down a second set of components.

23 . The battery management system of claim 22 wherein the battery management system is configured to:

compare the sensor signal to a reference to provide a comparison with the reference; and

determine whether the sensor signal meets the first and/or second condition based on the comparison with the reference.

24 . The battery management system of claim 22 wherein the first set of components comprises a power controller for controlling power to and/or from the rechargeable battery.

25 . The battery management system of claim 22 wherein the second set of components comprises at least one of: a network interface, for example a CAN interface, the at least one sensor and the controller.

26 . (canceled)

27 . An apparatus comprising:

a battery management system for a rechargeable battery;

a controller; and

at least one sensor for providing a sensor signal to the controller, the sensor signal relating to at least one of current and voltage supplied to and/or drawn from the rechargeable battery; wherein

the controller is configured to operate the battery management system in a low power mode in the event that the current and/or voltage is less than a selected threshold level.

28 . The apparatus of claim 27 wherein the controller is configured to:

compare the sensor signal to a reference at intervals; and

determine whether to operate in a low power mode based on the comparison with the reference in response to the sensor signal indicating that the current and/or voltage to and/or from the battery has not changed between intervals.

29 . (canceled)

30 . The battery management system of claim 27 wherein the low power mode comprises reducing power supplied to at least one component of the battery management system.

31 . The battery management system of claim 30 wherein the at least one component comprises at least one of: the at least one sensor, the controller, a power integrated controller, IC, balancing components for balancing charge in cells of the battery and a timer.

32 . The battery management system of claim 27 wherein the rechargeable battery comprises a plurality of cells and at least two terminals, and the low power mode comprises disconnecting at least one of the plurality of cells from the at least two terminals.

33 . (canceled)

34 . The battery management system of claim 27 wherein in response to at least one of:

a current flowing to and/or from the battery; and

a signal being received via at least one of a wireless interface, a serial interface and a CAN interface;

the controller is configured to exit the low power mode.

35 . The battery management system of claim 27 wherein in response to the received signals indicating that the current and/or voltage to and/or from the battery has not changed by a threshold for a second selected time period as determined by the timer, the controller is configured to operate in a second low power mode.

36 . The battery management system of claim 35 wherein the second low power mode comprises powering down the controller, and powering up the controller at intervals to listen for a change in the current and/or voltage supplied to and/or drawn from the battery.

37 .- 81 . (canceled)