Battery charger for towed vehicles and the like

• US 6,166,516 A
• Filed: 11/09/1998
• Issued: 12/26/2000
• Est. Priority Date: 11/09/1998
• Status: Expired due to Term

• Current Assignee: Horizon Global Americas Inc. (Horizon Global Corporation)
• Original Assignee: Tekonsha Engineering Company
• Inventors: Eccleston, Larry, Smith, Bruce E., Morse, Dennis M., Albright, Marcia S.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US09/189,015
• Time in Patent Office: 778 Days
• Field of Search: 320/105, 320/104, 320/144
• US Class Current: 320/104
• CPC Class Codes: H02J 2207/40 adapted for charging from various sources, e.g. AC, DC or multivoltage
• CPC Class Codes: H02J 7/342 The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging with circuits for polarity protection H02J7/0034

Abstract

An electrical charging circuit for applying a controlled charge to a receiving device, such as a battery, and particularly such as a battery carried on a towed vehicle such as a trailer for actuating the trailer brakes during emergency situations such as unexpected disconnection from the towing vehicle, i.e., break-away. In a basic sense, the charging circuit includes a voltage potential-responsive element or component for sensing the charged level of the receiving device coupled to the circuit and enabling or disabling the circuit charging operation, together with a variable-conductance circuit component for producing a generally constant charging voltage output to the receiving device over a wide range of applied voltages but also operable to provide a first amount of current flow to the receiving device at a given applied voltage and temperature but a second a limited amount of current flow when the voltage across the charging circuit is sufficiently large. In its most preferred embodiment, the voltage responsive component may be a diode switch, and the variable-conductance circuit component may be a positive temperature coefficient (PTC) thermistor.

Claims

1. An electrical charging circuit for applying a controlled charge to a receiving device, comprising:

a voltage potential-responsive component for sensing the charge level of a receiving device coupled thereto; and

a variable-conductance circuit component for producing a generally constant charging current output over a wide range of applied voltages, said variable-conductance component being serially coupled to said voltage potential-responsive component and operable to provide a first amount of current flow to said receiving device at a given applied voltage and temperature but to limit such current when the voltage differential across the charging circuit is sufficiently large to create a predetermined greater amount of current flow in said circuit and to said receiving device.

2. The electrical charging circuit as set forth in claim 1, wherein said variable-conductance circuit component comprises a positive-temperature-coefficient device.

3. The electrical charging circuit as set forth in claim 2, wherein said positive-temperature-coefficient device comprises a PTC thermistor component.

4. A battery maintenance device for insuring that a secondary battery mounted on a vehicle is sufficiently charged to actuate an electrically powered apparatus on that vehicle, including:

a charging circuit having an input to be electrically coupled between a power source and the secondary battery, wherein the charging circuit includes a voltage-responsive switch serially coupled to a PTC thermistor, wherein the PTC thermistor produces a generally constant charging current output over a wide range of applied voltages.