Method and apparatus for dynamically charging a battery

• US 5,331,268 A
• Filed: 08/02/1993
• Issued: 07/19/1994
• Est. Priority Date: 08/02/1993
• Status: Expired due to Term

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Fiske, John D. II, Patino, Joseph, Nigro, Daniel M.
• Primary Examiner(s): KINCAID, KRISTINE LYNN
• Application Number:
  US08/100,235
• Time in Patent Office: 351 Days
• Field of Search: 320/20, 320/21, 320/22, 320/23, 320/24, 320/39, 320/40, 320/43, 320/44
• US Class Current: 320/158
• CPC Class Codes: H02J 7/007182 in response to battery voltage

Abstract

A charger (302) determines the voltage baseline of a battery (306) and establishes a voltage range based on the voltage baseline of battery (306). Once the rapid charge rate has terminated and the trickle charge rate commenced, charger (302) monitors the voltage of the battery in order to make sure the battery is not being depleted. If the battery voltage is above the established range, the trickle charge rate is decreased, and if the battery voltage is below the voltage range, the trickle charge rate is increased.

Claims

1. A method for dynamically charging a battery having a voltage, comprising the steps of:

determining a dynamic baseline voltage for the battery after the battery has been charged for a predetermined period of time;

establishing a voltage range based on the dynamic baseline voltage;

charging the battery at a predetermined charge rate;

monitoring the voltage of the battery; and

adjusting the rate at which the battery is being charged if the voltage of the battery falls outside of the voltage range.

2. A method for dynamically charging a battery as defined in claim 1, wherein the step of establishing a voltage range, comprises the steps of:

using the dynamic baseline voltage as an upper threshold of the voltage range; and

subtracting a predetermined voltage amount from the dynamic baseline voltage in order to determine a lower threshold of the voltage range.

3. A method for dynamically charging a battery as defined in claim 1, wherein the step of determining the dynamic baseline voltage, comprises the sub-steps of:

determining that the battery has been charged to a predetermined level; and

measuring the voltage of the battery a plurality of times.

4. A method for dynamically charging a battery as defined in claim 2, wherein the step of adjusting the rate at which the battery is being charged, comprises the steps of:

lowering the charge rate if the voltage of the battery is higher than the upper threshold; and

increasing the charge rate if the voltage of the battery is lower than the lower threshold.

5. A method for dynamically charging a battery as defined in claim 3,

wherein the step of determining that the battery has been charged to a predetermined level further comprises:

determining that the change in temperature of the battery over a certain time period equals a predetermined value.

6. A battery charger for charging a battery having a voltage, comprising:

a charging means for charging the battery;

a controller coupled to the charging means, comprising;

means for monitoring the voltage of the battery;

means for determining a dynamic baseline voltage for the battery after the battery has been charged for a predetermined period of time by the charging means;

means for establishing a voltage range based on the dynamic baseline voltage of the battery; and

the controller further comprises a means for adjusting the rate at which the battery is being charged by the charging means if the voltage of the battery falls outside of the voltage range.

7. A battery charger for charging a battery as defined in claim 6, wherein the means for adjusting the rate at which the battery is being charged increases the rate at which the charging means charges the battery if the means for monitoring the voltage of the battery determines that the voltage of the battery is below the voltage range and decreases the rate at which the charging means charges the battery if the means for monitoring the voltage of the battery determines that the voltage of the battery is above the voltage range.

8. A battery charger for charging a battery as defined in claim 6,

wherein the controller further comprises a storage means for storing a voltage level;

and

the means for establishing a voltage range uses the dynamic baseline voltage as an upper threshold level of the voltage range and subtracts the voltage level stored in the storage means from the dynamic baseline voltage in order to establish a lower threshold level of the voltage range.

9. A battery charger for charging a battery as defined in claim 6, wherein the controller is a microprocessor.