Information handling system battery charge management to support quick start

1. A portable information handling system comprising:

a planar housing;

a processor disposed in the planar housing and operable to execute instructions to process information;

a memory disposed in the planar housing and interfaced with the processor, the memory operable to store the information;

a display disposed in the planar housing and interfaced with the processor and memory, the display operable to present the information as visual images;

a battery disposed in the housing and operable to power the processor, memory and display;

a battery switch interfaced with the battery and operable to disconnect the battery from providing power to the processor, memory and display;

a power manager disposed in the housing and operable to manage power applied by the battery for powering the processor, memory and display, and operable to accept power applied from an external charger for powering the processor, memory and display, and for charging the battery; and

a battery charge manager interfaced with the battery switch and power manager, the battery charge manager operable to determine a minimum battery charge level and to activate the switch to disconnect the battery at the minimum charge level;

wherein the processor, memory and display have surge current operational states that draw current in excess of current available from the external charger and the minimum battery charge level comprises a battery charge reserve sufficient to supplement external charger current during the surge current operational states.

2. The portable information handling system of claim 1 wherein the minimum charge level comprises a battery charge reserve sufficient to power a boot of an operating system on the processor to an operational state.

3. The portable information handling system of claim 1 wherein the minimum charge level comprises a battery charge sufficient to power a boot of an operating system on the processor to an operational state in cooperation with the external charger.

4. The portable information handling system of claim 1 wherein the battery charge manager is further operable to detect power applied by the external charger and, in response to the detecting, to connect the battery with the switch to accept power for charging the battery from the external charger.

5. The portable information handling system of claim 1 wherein the battery charge manager adapts the minimum battery charge level based on battery age.

6. The portable information handling system of claim 1 wherein the battery charge manager adapts the minimum battery charge level based on an available charge current detected during charge events of the battery.

7. The portable information handling system of claim 1 wherein the battery charge manager adapts the minimum battery charge level based on current consumption detected during boot events.

8. The portable information handling system of claim 1 wherein the battery switch comprises a FET having an input interfaced with an external power source to automatically connect the battery if an external power source is applied to charge the battery.

9. A portable information handling system power system comprising:

a battery operable to store a charge for power processing components through a battery discharge path of the portable information handling system;

an external power supply operable to accept external power for powering the processing components and charging the battery;

a battery charger interfacing with the external power supply and battery;

a switch disposed in the battery discharge path and operable to selectively connect and disconnect the battery with the battery discharge path; and

a power controller interfaced with the external power supply, the battery charger and the switch, the power controller operable to command the switch to disconnect the battery from the battery discharge path to maintain a minimum battery charge of above an amount needed to boot an operating system of the portable information handling system to an operational state;

wherein the external power supply provides current at a level insufficient to meet current demand during current surge operational states and the minimum battery charge comprises a battery charge reserve sufficient to supplement external charger current during the current surge operational states.

10. The portable information handling system power system of claim 9 wherein the minimum battery charge further comprises an amount needed to boot the operating system of the portable information handling system to an operational state when boot is initiated with external power applied by the external power supply.

11. The portable information handling system power system of claim 10 wherein the power controller is further operable to:

detect application of external power by the external power supply; and

in response to detecting, to connect the battery to the battery discharge path.

12. The portable information handling system power system of claim 10 wherein the power controller determines the minimum battery charge at least in part from battery age.

13. The portable information handling system power system of claim 10 wherein the power controller determines the minimum battery charge at least in part from an expected external power supply current available at boot of the portable information handling system.

14. The portable information handling system power system of claim 10 wherein the power controller determines the minimum battery charge at least in part from an expected power draw at boot of the portable information handling system.