Method and apparatus for indicating a low battery level

• US 9,488,695 B2
• Filed: 12/15/2014
• Issued: 11/08/2016
• Est. Priority Date: 12/17/2013
• Status: Expired due to Fees

• Current Assignee: Braun GmbH (The Procter & Gamble Company)
• Original Assignee: Braun GmbH (The Procter & Gamble Company)
• Inventors: Simeth, Martin
• Primary Examiner(s): Memula, Suresh
• Application Number:
  US14/570,923
• Publication Number:
  US 20150168501A1
• Time in Patent Office: 694 Days
• Field of Search: 320/134
• US Class Current: 1/1
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method and an apparatus for determining the battery level of a rechargeable battery used in a battery driven apparatus for driving a load and for indicating a low battery level; and a repeating measurement of the battery voltage and a determination of a threshold for indicating the low battery level. The running time of the apparatus while driving the load is accumulated since the last charging and is repeatedly stored as sequenced data-logger entries in a data-logger memory until a reset of the apparatus due to insufficient battery capacity or until charging of the battery. Threshold is determined after the reset based on the data-logger entries and a required remaining running time of the apparatus upon indication of low battery level.

Claims

1. A method for determining the battery level of a rechargeable battery (3) used in a battery-driven apparatus (1) for driving a load (2) and for indicating a low battery level after a last charging, the method comprising a repeating measurement of the battery voltage and a determination of a threshold for indicating the low battery level, wherein the running time of the apparatus (1), while driving the load (2), is accumulated since the last charging, the accumulated running time is repeatedly stored as sequenced data-logger entries (9) in a data-logger memory (7) until a reset of the apparatus (1) due to insufficient battery capacity or until charging of the battery (3), and wherein the threshold is determined after a reset of the apparatus (1) based on the data-logger entries (9) and a required remaining running time of the apparatus (1) upon indication of low battery level.

2. The method according to claim 1, wherein the battery voltage is repeatedly measured as a function of the accumulated running time and stored in the data-logger memory together with the accumulated running time as sequenced data-logger entries containing the measured battery voltage and the accumulated running time during the measurement.

3. The method according to claim 1, wherein the threshold is determined by evaluating the data-logger entries going backwards in running time from the latest data logger entry before the reset of the apparatus.

4. The method according to claims 2, wherein the threshold is determined as the measured battery voltage of the one data-logger entry with the accumulated running time corresponding to the difference between the latest accumulated running time before the reset of the apparatus and the required remaining running time.

5. The method according to claim 4, wherein the initial low battery voltage threshold is set to zero.

6. The method according to claim 1, wherein the threshold is determined as low battery accumulated running time value corresponding to a difference between the latest accumulated running time before the reset of the apparatus and the required remaining running time.

7. The method according to claim 6, wherein the initial low battery accumulated running time value is set to a value far below the maximum accumulated running time obtainable with the rechargeable battery.

8. The method according to claim 1, wherein an accumulated low-level running time is determined starting with the indication of low battery level until a reset of the apparatus due to insufficient battery capacity or until charging of the battery, and wherein the threshold for indicating the low battery level is lowered if the accumulated low-level running time is exceeding the required remaining running time.

9. The method according to claim 8, wherein lowering of the threshold is corresponding to the difference between the accumulated low-level running time and the required remaining running time.

10. An apparatus having a load (2), a rechargeable battery (3) for driving the load (2), an indicator (4) for low battery level, and a processor (5) with a memory (6), the processor being adapted to control the indicator for low battery level, wherein the processor is structured and configured to perform the method of claim 1 and wherein the memory comprises a data-logger memory (7).

11. The apparatus according to claim 10, wherein the data logger memory is a non-volatile memory.

12. The apparatus according to claim 10, wherein the apparatus is selected from the group consisting of an electric toothbrush and an electric shaver.

13. A computer-program product having a program code stored on a computer-readable medium for carrying out the method of claim 1, wherein the computer-program product is executed on a processor (5) of an apparatus (1) having a load (2), a rechargeable battery (3) for driving the load (2), an indicator (4) for low battery level, and the processor (5) with a memory (6).