Recharging battery charger

• US 4,742,290 A
• Filed: 06/02/1986
• Issued: 05/03/1988
• Est. Priority Date: 06/02/1986
• Status: Expired due to Fees

• Current Assignee: Associated Equipment Corporation (Associated Equipment)
• Original Assignee: Acme Electric Corp. (Hubbell, Inc.)
• Inventors: Bell, Steven R., Sutphin, Richard C., Monsell, Kurt
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Ault, Anita M.
• Application Number:
  US06/869,973
• Time in Patent Office: 701 Days
• Field of Search: 320/20, 320/21, 320/23, 320/24, 320/32, 320/39, 320/40, 320/44
• US Class Current: 320/149
• CPC Class Codes: H02J 7/007184 in response to battery voltage gradient
• 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 320/19 Charger status, e.g. voltmeter
• CPC Class Codes: Y10S 320/24 Inductor

Abstract

A microprocessor controlled battery charger to charge a battery when the charging current is reduced to zero even though the charger is still connected to the battery. The microprocessor includes a means to read the voltage of the battery and also includes a timer. The voltage of the battery is periodically read and when it decreases below a predetermined value the microprocessor again establishes recharging of the battery first at an intermediate rate until either a maximum voltage is reached or a minimum dv/dt is reached and then the current is reduced to a lower current rate for a finishing charge of the battery for a given period of time.

Claims

1. A microprocessor controlled battery charger adapted to be connected to a battery to be charged, said battery charger comprising, in combination:

means to read the voltage of the battery;

a microprocessor to establish a charging of said battery by said charger until substantially fully charged and then terminating said charging;

said reading means at least periodically reading the voltage of the battery after the termination of charging and determining if the battery voltage has decreased below a predetermined value;

said microprocessor establishing recharging of the battery at a first charging rate until the rate of change of voltage with time is less than x/100 volts per hour at which time the current is reduced to a second charging rate for a finishing charge of the battery, where x is a positive number; and

selector means to select the values of said first and second charging rates.

2. A battery charger as set forth in claim 1, including

a timer connected to said microprocessor;

and

said reading means periodically reading the battery voltage during a period of time as determined by said timer.

3. A battery charger as set forth in claim 1, wherein said microprocessor establishes said second charging rate in the absence of a first rate being selected by said selector means.

4. A battery charger as set forth in claim 1, wherein said selector means is a digital key pad input.

5. A battery charger as set forth in claim 1, wherein said battery charger is a switching battery charger.

6. A battery charger as set forth in claim 1, including a timer, and wherein said microprocessor establishes said finishing charge second rate for a timed period.

7. A battery charger as set forth in claim 1, wherein said microprocessor controls said first charging rate to be at a constant current despite changing battery voltage.

8. A battery charger as set forth in claim 1, wherein said microprocessor controls said second charging rate to be at a constant lower current rate than said first charging rate despite changing battery voltage.

9. A battery charger as set forth in claim 1, wherein said microprocessor controls change from said first to said second charging rate at the first to occur of one of a predetermined maximum battery voltage and the rate of change of voltage being less than x/100 volts per hour.