Battery charger and method utilizing alternating DC charging current

• US 20070114970A1
• Filed: 07/14/2006
• Published: 05/24/2007
• Est. Priority Date: 07/15/2005
• Status: Active Grant

• Current Assignee: Schumacher Electric Corporation
• Original Assignee: Schumacher Electric Corporation
• Inventors: Whiting, John, Johnson, Thomas, Waldron, John
• Granted Patent: US 8,237,412 B2
• Time in Patent Office: Days
• US Class Current: 320/128
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters

Abstract

A battery charger is disclosed for use with various batteries, such as automotive and marine-type batteries. In accordance with an aspect of the invention, the charging current is alternated between non-zero DC charging current levels. By alternating the charging current between non-zero DC charging levels, the battery can be charged to a higher capacity (i.e., ampere hours) faster, thus reducing the charging time and at the same time allow the rating of the battery charger to be increased. In accordance with another important aspect of the invention, the technique for alternating the charging current can be implemented in both linear and switched-mode battery chargers.

Claims

1. A battery charger comprising:

a battery charging circuit for providing a battery charging current for charging a battery, said battery charging current circuit configured to provide average DC charging values that alternate between two non-zero average DC values defining afast charging waveform having a low average DC charging current and a relatively higher average DC charging current.

2. The battery charger as recited in claim 1, wherein said battery charging current is a linear battery charger.

3. The battery charger as recited in claim 1, wherein said battery charging current is a switched-mode battery charger.

4. The battery charger as recited in claim 1, wherein said fast charging waveform is a square wave.

5. The battery charger as recited in claim 1, wherein said fast charging waveform ramps up from said lower average DC charging current to said higher average DC charging current.

6. The battery charger as recited in claim 1, wherein said fast charging waveform ramps down from said higher average DC charging current to said lower average DC charging current.

7. The battery charger as recited in claim 1, wherein said fast charging waveform ramps up from said lower average DC charging current to said higher average DC charging current and said fast charging waveform ramps down from said higher average DC charging current to said lower average DC charging current.

8. The battery charger as recited in claim 1, wherein the duty cycle of said fast charging waveform varies as a function of the battery charge.

9. The battery charger as recited in claim 1, wherein said battery charger is configured with a plurality selectable charge rates.

10. The battery charger as recited in claim 9, wherein said battery charger is configured so that said fast charging waveform is automatically generated when one or more of said selectable charge rates are selected.

11. The battery charger as recited in claim 1, wherein said higher and lower average DC charging currents are constant over a charging cycle.

12. The battery charger as recited in claim 1, wherein said higher and lower average DC charging currents are not constant over a charging cycle.

13. A method for charging a battery comprising the steps of:

(a) charging said battery at a first average DC charging current; and

(b) subsequently charging said battery at a second average DC charging current defining a fast charging waveform.

14. The method as recited in claim 13, further including the step of:

(c) charging said battery with said fast charge waveform at one or more selectable charge rates.

15. A battery charger comprising:

a battery charging circuit configured with a plurality of selectable charging levels and further configured so that at one charging level the charging current is comprised of at least two average DC charging currents during a charging cycle defining a fast charge waveform that is automatically generated when of said selectable charging levels is selected.

16. The battery charger as recited in claim 15, wherein said battery charging circuit is a linear battery charger.

17. The battery charger as recited in claim 15, wherein said battery charging circuit is a switched-mode battery charger.