Rechargeable battery pack onboard charge state indicator
Battery pack for use with a portable device, including colored LEDs for presenting a high granularity battery charge state, are disclosed. One embodiment includes a red and a green LED, wherein solid and blinking patterns are presented by the LEDs to correspond to a relative battery charge state. Other battery state indications, such as failure states, may also be presented on the colored LEDs.
1 . A buried utility locator, comprising:
an AC magnetic field sensing locator for determining position information for one or more hidden or buried utilities; and
a battery pack removably coupled to the locator for providing power thereto, the battery pack comprising:
a housing including a mechanical attachment mechanism for removably coupling the battery pack to the locator;
a rechargeable battery cell assembly positioned within the housing;
an electrical power and charging connector assembly for electrically coupling the battery cell terminals to the locator and to a battery charger;
an electronic circuit operatively coupled to the battery cell assembly, including:
a battery charge state monitoring circuit for receiving a signal associated with a charge state of the battery cell assembly and generating a charge state status output;
a lighting element driver circuit; and
an output display element, including two or more differently colored lighting elements, operatively coupled to the driver circuit such that the lighting elements provide:
when the battery charge state is above a predefined intermediate charge state threshold, a first steady light output signal from a first of the colored lighting elements and a first varying light output signal from a second of the colored lighting elements, wherein the first varying light output signal reflects a decrease from a fully charged state of the battery cell assembly when the battery charge state is above a predefined intermediate charge state threshold; and
when the battery charge state is below the predefined intermediate charge state threshold, a second varying light output signal from the first of the colored lighting elements and a first steady light output signal from the second of the colored lighting elements, wherein the second varying light output signal reflects a decrease from a fully charged state of the battery cell assembly when the battery charge state is below the predefined intermediate charge state threshold; and
wherein the varying light output signals are duty-cycle modulated signals, wherein the duty-cycle is proportionate with a current charge state of the battery pack.
2 . The locator of claim 1 , wherein the two or more differently colored lighting elements include a green lighting element as the first of the colored lighting elements and a red lighting element as the second of the colored lighting elements.
3 . The locator of claim 2 , wherein the red and green lighting elements are light emitting diodes (LEDs).
4 . The locator of claim 3 , wherein the predefined intermediate charge threshold is a half charged state.
5 . The locator of claim 1 , wherein the varying light output signals are flashing rate of the flashing sequences is proportional to a current charge state of the battery pack.
6 . The locator of claim 3 , wherein a failure mode code pattern is provided from one or more of the lighting elements when a battery pack failure mode is sensed.
7 . The locator of claim 4 , wherein the failure mode code pattern is a Morse Code SOS pattern.
8 . The locator of claim 5 , further including a charge state legend on the battery pack housing, wherein the charge state legend illustrates the charge state presented by the colored lighting elements as a function of battery charge.
9 . The locator of claim 6 , wherein the legend illustrates the charge state in solid segments and oval segments corresponding to the display output of the multicolored lighting elements.
10 . The locator of claim 1 , wherein the battery pack further includes electronics for transferring data between the battery pack and the locator, and wherein the data transfer is presented by a display sequence on the colored lighting elements.