BATTERY CHARGER WITH AUTOMATIC VOLTAGE DETECTION

• US 20140021906A1
• Filed: 09/20/2013
• Published: 01/23/2014
• Est. Priority Date: 07/16/2009
• Status: Active Grant

• Current Assignee: Schumacher Electric Corporation
• Original Assignee: Schumacher Electric Corporation
• Inventors: Heins, Matthew A., Whiting, John
• Granted Patent: US 8,922,172 B2
• Time in Patent Office: Days
• US Class Current: 320/107
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00041 in response to measured battery parameters, e.g. voltage, current or temperature profile
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery charger is disclosed that is configured to be connected to an external battery by way of external battery cables. In accordance with an important aspect of the invention, the battery charger is configured with automatic voltage detection which automatically determines the nominal voltage of the battery connected to its battery charger terminals and charges the battery as a function of the detected nominal voltage irrespective of the nominal voltage selected by a user. Various safeguards are built into the battery charger to avoid overcharging a battery. For battery chargers with user selectable nominal battery voltage charging modes, battery charger is configured to over-ride a user selected battery voltage mode if it detects that the battery connected to the battery charger terminals is different than the user selected charging mode.

Claims

1. A battery charger comprising:

a pair of battery charger terminals;

a measuring system for measuring the voltage of a battery connected across said battery charger terminals;

an automatic voltage detection for automatically determining the nominal voltage of the battery connected across the battery charger terminals by measuring an open circuit voltage of the battery by way of said measuring system and determining the nominal voltage of the battery based upon a measured peak ripple voltage across the battery charger terminals in response to a test current when the open circuit voltage of the battery is less than a predetermined value; and

a charging system for automatically charging the battery as a function of the nominal voltage determined by said automatic voltage detection system

2. The battery charger as recited in claim 1, wherein said measuring system measures the battery open circuit voltage.

3. The battery charger as recited in claim 1, wherein said measuring system measures the battery closed circuit voltage.

4. The battery charger as recited in claim 1, wherein said charging system includes a user selectable voltage mode.

5. The battery charger as recited in claim 1, wherein said charging system does not include a user selectable voltage mode.

6. The battery charger as recited in claim 4, wherein said charging system automatically over rides the user selected voltage mode when said automatic voltage detection system determines that the nominal battery voltage is different than the selected voltage mode.

7. The battery charger as recited in claim 1, wherein said automatic voltage detection system is configured to determine whether a battery is connected to the battery charger.

8. The battery charger as recited in claim 1, wherein said automatic voltage detection system is configured to check for a sulfation condition.

9. The battery charger as recited in claim 1, wherein said charging system is configured to run in a desulfation mode.

10. The battery charger as recited in claim 1, wherein said charging system is configured to alternatively charge a 6 volt battery or a 12 volt battery.

11. The battery charger as recited in claim 10, wherein the automatic voltage detection system can determine whether the nominal voltage of the battery is 6 volt or a depleted 12 volt battery when said battery voltage is at or less than a predetermined voltage greater than 6 volts and less than 12 volts.

12. The battery charger as recited in claim 11, wherein said predetermined voltage is 7.5 volts.

16. The method as recited in claim 2, wherein step (a) comprises:

automatically determining the nominal battery voltage of the battery connected to the battery cables is 6 volts DC or 12 volts DC when said open circuit voltage is less than 7.5 volts.

17. The battery charger as recited in claim 1, wherein said automatic voltage detection system forces a test current through the battery for a predetermined amount of time when the open circuit voltage of the battery connected to the battery charger terminals is less than said predetermined value and the peak ripple voltage is measured by said measuring system and the nominal battery voltage of the battery connected to the battery charger terminals is selected as a function of the peak ripple voltage.

18. The battery charger as recited in claim 1, wherein said automatic voltage detection system determines the nominal voltage of the battery connected to the battery charger terminals when the open circuit voltage of the battery is equal to or greater than or equal to said predetermined value.

13. A method for charging a battery connected to a battery charger by way of a pair of battery cables, the method comprising the steps of:

(a) automatically determining the nominal battery voltage of the battery connected to the battery cables as a function of the open circuit voltage and if the open circuit voltage is less than a predetermined voltage, the nominal battery voltage is determined as a function of a measured peak ripple voltage across the battery in response to a test current; and

(b) automatically charging the battery in accordance with the nominal battery voltage of the battery connected to the battery cables, as determined in step (b).

14. The method as recited in claim 13, further including the step of initially detecting automatically whether a battery is connected to the battery charger terminals.

15. The method as recited in claim 13, wherein step (b) comprises:

automatically determining the nominal battery voltage of the battery connected to the battery cables is 6 volts DC or 12 volts DC.

19. A battery charger comprising:

a pair of battery charger terminals;

an automatic voltage detection system for automatically determining the nominal voltage of the battery connected across the battery charger terminals by determining the nominal voltage of the battery based upon the open circuit voltage of the battery when the open circuit voltage is greater than or equal to a predetermined value and when said open circuit voltage is less than said predetermined value, determining the nominal voltage of the battery as a function of a measured peak ripple voltage across the battery in response to a test current; and

a charging system for automatically charging the battery as a function of the nominal voltage determined by said automatic voltage detection system.

20. The battery charger as recited in claim 19 wherein said battery charger is configured to differentiate between a 6 volt battery and a 12 volt battery.