Staggered backup battery charging system

• US 7,646,172 B2
• Filed: 06/18/2007
• Issued: 01/12/2010
• Est. Priority Date: 11/18/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Jones, Carl E.
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): DIAO, M BAYE
• Application Number:
  US11/764,639
• Publication Number:
  US 20070236185A1
• Time in Patent Office: 939 Days
• Field of Search: 320/116, 320/128, 320/132, 320/134, 320/135, 320/148, 320/DIG.12, 320/DIG.19, 320/DIG.21, 320/103, 320/104, 320/110, 320/112, 320/118, 320/119, 703/28, 703/64, 307/9.1, 307/10.1, 307/10.7, 307/46, 324/427, 324/432, 324/434
• US Class Current: 320/132
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence

Abstract

A battery backup system includes a control device including a power sensing device, a discharge circuit, a charging circuit, and a plurality of battery packs. A lower threshold is established representative of a minimum acceptable effective energy capacity. Each battery pack is recharged if its effective energy capacity falls below the lower threshold. Additionally, an upper threshold is established representative of the minimum acceptable effective energy capacity plus a performance margin. In a two battery-pack system, if both battery packs fall below the upper threshold, the battery with the least effective energy capacity is discharged to the minimum acceptable effective energy capacity and then recharged to the battery pack'"'"'s maximum energy capacity. In this way, both battery packs are prevented from approaching the minimum acceptable effective energy capacity at the same time. This reduces the size or number of battery packs and reduces their associated cost and volume.

Claims

1. An article of manufacture including a data storage medium, said data storage medium including a set of machine-readable instructions that are executable by a processing device to implement an algorithm, said algorithm comprising the steps of:

detecting when a first energy capacity of a first battery pack and a second energy capacity of a second battery pack fall below a lower threshold;

comparing the first energy capacity to a second energy capacity of a second battery pack, determining which of the first battery pack and the second battery pack has the lower energy capacity;

directing a charging circuit to charge the battery pack with the lower energy capacity to its maximum energy capacity;

detecting when the first energy capacity and the second energy capacity fall below an upper threshold; and

charging the first battery pack to the first maximum energy capacity.

2. The article of manufacture of claim 1, further comprising the step of discharging the first battery pack to the lower threshold before the step of charging the first battery pack to the first maximum energy capacity.

3. The article of manufacture of claim 1, further comprising the steps of:

detecting a third energy capacity of a third battery pack;

detecting when any two of the energy capacities have fallen below the upper threshold; and

charging the first battery pack to the first maximum energy capacity.

4. The article of manufacture of claim 1, further comprising the steps of:

detecting a third energy capacity of a third battery pack;

detecting when the first, second, and third energy capacities have fallen below the upper threshold; and

charging the first battery pack to the first maximum energy capacity.

5. The article of manufacture of claim 3, further comprising the step of discharging the first battery pack to the lower threshold before the step of charging the first battery pack to the first maximum energy capacity.

6. The article of manufacture of claim 4, further comprising the step of discharging the first battery pack to the lower threshold before the step of charging the first battery pack to the first maximum energy capacity.

7. A method of providing a service for managing a support system, comprising integrating computer-readable code into a computing system, wherein the computer-readable code in combination with the computing system is capable of performing the following steps:

detecting when a first energy capacity of a first battery pack and a second energy capacity of a second battery pack fall below a lower threshold;

comparing the first energy capacity to a second energy capacity of a second battery pack, determining which of the first battery pack and the second battery pack has the lower energy capacity; and

,

directing a charging circuit to charge the battery pack with the lower energy capacity to its maximum energy capacity.

detecting when the first energy capacity and the second energy capacity fall below an upper threshold; and

charging the first battery pack to the first maximum energy capacity.

8. The method of claim 7, further comprising the step of discharging the first battery pack to the lower threshold before the step of charging the first battery pack to the first maximum energy capacity.

9. The method of claim 7, further comprising the steps of:

detecting a third energy capacity of a third battery pack;

detecting when any two of the energy capacities have fallen below the upper threshold; and

charging the first battery pack to the first maximum energy capacity.

10. The method of claim 7, further comprising the steps of:

detecting a third energy capacity of a third battery pack;

detecting when the first, second, and third energy capacities have fallen below the upper threshold; and

charging the first battery pack to the first maximum energy capacity.

11. The method of claim 9, further comprising the step of discharging the first battery pack to the lower threshold before the step of charging the first battery pack to the first maximum energy capacity.

12. The method of claim 10, further comprising the step of discharging the first battery pack to the lower threshold before the step of charging the first battery pack to the first maximum energy capacity.