Automatic battery charger

• US 4,207,513 A
• Filed: 02/10/1978
• Issued: 06/10/1980
• Est. Priority Date: 02/10/1978
• Status: Expired due to Term

• Current Assignee: Power Controls Corporation
• Original Assignee: Power Controls Corporation
• Inventors: Hess, John S. Jr.
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US05/876,600
• Time in Patent Office: 851 Days
• Field of Search: 320/22-24, 320/32,39, 320/21, 320/37, 320/38
• US Class Current: 320/125
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: Y10S 320/12 Precharging analysis, e.g. determining presence of battery
• CPC Class Codes: Y10S 320/13 Fault detection
• CPC Class Codes: Y10S 320/15 Polarity control

Abstract

A battery charger is provided for industrial storage batteries which includes both digital and analog control circuits for controlling the charging voltage to maintain a charging cycle in which the current is initially held to a maximum value until the cell voltage rises to a preset level, after which the cell voltage is maintained constant at this level until a preset minimum current is reached, and the minimum current is then maintained for a fixed period of time. The charger requires no adjustments for ampere-hour rating or for number of cells in the battery, and is capable of charging batteries of any ampere-hour rating over a wide range, without any adjustment.

Claims

1. A battery charging system for charging storage batteries of any ampere-hour rating without adjustment, said system comprising a power source for applying a charging voltage to a battery to be charged, first means responsive to battery charging current for initially controlling said charging voltage to maintain a predetermined maximum charging current until the battery cell voltage has reached a predetermined value, means responsive to battery voltage per cell for thereafter controlling said charging voltage to maintain the battery cell voltage at said predetermined value until the charging current falls to a predetermined minimum value, second means responsive to the charging current for controlling the charging voltage to maintain said minimum charging current, timer means for terminating the charging operation after the minimum charging current has been maintained for a predetermined time, and means actuable in response to a rise in battery current above said minimum current value for resetting said timer means whereby the minimum charging current will be maintained for said predetermined time after charging current again falls to said predetermined minimum value.

2. A battery charging system for charging storage batteries of any ampere-hour rating without adjustment, said system comprising a power source for applying a controllable charging voltage to a battery to be charged, first means responsive to battery charging current for initially controlling said charging voltage to maintain a predetermined maximum charging current until the battery cell voltage has reached a predetermined value, means responsive to the battery cell voltage for thereafter controlling said charging voltage to maintain the battery cell voltage at said predetermined value until the charging current falls to a predetermined minimum value which is independent of the ampere-hour rating of the battery, second means responsive to the charging current for controlling the charging voltage to maintain said minimum charging current, and means for terminating the charging operation after the minimum charging current has been maintained for a predetermined time, said means for terminating including a digital counter, means for continuously supplying clock pulses to said counter, means controlled by said second means responsive to charging current for permitting the counter to run continuously as long as the battery current does not exceed said minimum current for more than a predetermined time, said counter providing an output signal after a predetermined period of continuous running, and means responsive to said output signal for effecting termination of the charging operation.

3. The battery charging system of claim 2 including means for resetting said counter when battery current exceeds said minimum current.