Battery charger with automatic voltage detection

• US 8,922,172 B2
• Filed: 09/20/2013
• Issued: 12/30/2014
• Est. Priority Date: 07/16/2009
• Status: Active Grant

• Current Assignee: Schumacher Electric Corporation
• Original Assignee: Schumacher Electric Corporation
• Inventors: Whiting, John, Heins, Matthew A.
• Primary Examiner(s): DIAO, M BAYE
• Application Number:
  US14/032,374
• Publication Number:
  US 20140021906A1
• Time in Patent Office: 466 Days
• Field of Search: 320/149, 320/162, 320/107, 324/426
• US Class Current: 320/149
• 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;

an automatic voltage detection system for automatically determining a nominal voltage of a battery connected across the pair of battery charger terminals by measuring a first voltage of the battery across the pair of battery charger terminals and, if the first voltage of the battery is less than a first predetermined value, determining the nominal voltage of the battery by measuring a second voltage across the pair of battery charger terminals and comparing the second voltage of the battery to a second 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 the second voltage is measured in response to a test current forced through said battery.

3. The battery charger as recited in claim 1, wherein the first voltage is a battery open circuit voltage.

4. The battery charger as recited in claim 1, wherein the second voltage is a ripple voltage.

5. The battery charger as recited in claim 1, wherein the second voltage is a peak voltage.

6. The battery charger as recited in claim 1, wherein the second voltage is a peak ripple voltage.

7. The battery charger as recited in claim 2, wherein said automatic voltage detection system forces said test current through said battery for a predetermined amount of time.

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

9. 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.

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

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

12. The battery charger as recited in claim 1, wherein the automatic voltage detection system can determine whether the nominal voltage of the battery is a 6 volt battery or a depleted 12 volt battery when said first voltage is less than or equal to the 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 pair of battery cables as a function of a first voltage and if the first voltage is less than a predetermined voltage, the nominal battery voltage is determined as a function of a second voltage across the battery; and

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

14. The method as recited in claim 13, wherein the second voltage is measured in response to a test current.

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

16. The method as recited in claim 13, wherein step (a) further comprises automatically determining whether the nominal battery voltage of the battery connected to the pair of battery cables is 6 volts DC or 12 volts DC.

17. The method as recited in claim 13, further including the steps of (i) automatically measuring the first voltage of the battery connected to the battery charger, and (ii) automatically determining whether the nominal battery voltage of the battery connected to the pair of battery cables is 6 volts DC or 12 volts DC when said first voltage is less than 7.5 volts.

18. A battery charger comprising:

a pair of battery charger terminals;

an automatic voltage detection system for automatically determining a nominal voltage of a battery connected across the pair of battery charger terminals, wherein the automatic voltage detection system

(i) measures a first voltage of the battery,

(ii) determines the nominal voltage of the battery based upon the first voltage of the battery if the first voltage is greater than or equal to a predetermined value, and

(iii) determines the nominal voltage of the battery as a function of a second voltage across the battery if said first voltage is less than said 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.

19. The battery charger as recited in claim 18, wherein the second voltage is measured in response to a test current.