Battery tester with high precision

• US 8,788,226 B2
• Filed: 03/22/2011
• Issued: 07/22/2014
• Est. Priority Date: 03/22/2011
• Status: Active Grant

• Current Assignee: DHC Specialty Corp.
• Original Assignee: DHC Speciality Corp.
• Inventors: Sheng, Hsien-Fang, Hsiao, Yuan-Chen
• Primary Examiner(s): Schechter, Andrew
• Assistant Examiner(s): Kessie, Daniel
• Application Number:
  US13/069,054
• Publication Number:
  US 20120245872A1
• Time in Patent Office: 1,218 Days
• Field of Search: 702/63
• US Class Current: 702/63
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/386 using test-loads
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health

Abstract

The present invention discloses a battery tester having high precision, which has a casing having an input device and two detecting wires, a microprocessor, a variable loading unit and a battery power status detecting unit. The microprocessor builds a strategic decision process therein to determine a proper resistance of a load for a battery according to the battery capacity, initial voltage and detection requirements having 1/N CCA and loading time. When the resistance of the load is determined, the microprocessor adjusts a resistance of the variable loading unit equal to the resistance of the load for the battery. Therefore, the battery tester does not use the load with the fixed resistance to detect batteries with different capacities and has accurate detecting results.

Claims

1. A battery tester with high precision, comprising a casing having an input device and two detecting wires, a microprocessor, a variable loading unit and a battery power status detecting unit, wherein:

the detecting wires are adapted to selectively connect to two electrodes of a battery;

the variable loading unit electronically connected to the microprocessor and connected to the detecting wires; and

the battery power status detecting unit is electronically connected to the microprocessor to detect a battery voltage and a battery current of the battery and to report the battery voltage and the battery current to the microprocessor; and

the battery tester is characterized in

the input device providing different options of CCA_B and 1/N CCA, with at least 2 options for N, where N is variable; and

the

microprocessor storing a strategic decision process and the strategic decision process having steps of;

(a) obtaining the battery voltage V_B of the battery and reading the CCA_B and the 1/N CCA from the input device;

(b) calculating an equation of loading resistance with the CCAB, an initial battery voltage and the 1/N CCA to obtain a proper loading resistance for the batter and adjusting a resistance of the variable loading unit in accordance with the calculated loading resistance; and

(c) executing a detecting process to obtain a detecting waveform.

2. The battery tester as claimed in claim 1, wherein the variable loading unit is a variable resistor having:

two ends respectively connected to the detecting wires; and

one controlling end electronically connected to the microprocessor such that the microprocessor adjusts the resistance of the variable resistor.

3. The battery tester as claimed in claim 2, wherein

the equation is:

4. The battery tester as claimed in claim 1, wherein the variable loading unit has multiple resistors and multiple switches electronically connected to the microprocessor, wherein one end of each resistor is connected to one of the detecting wires, and the other end of the resistors are respectively connected to the other detecting wire through the switches.

5. The battery tester as claimed in claim 1, wherein the variable loading unit has:

multiple resistors connected in serial to be a series of the resistors, wherein one end of the series of the resistors is connected to one of the detecting wires; and

a multiplexer having;

a common terminal connected to the other detecting wire;

multiple switching terminals respectively connected to serial nodes of the series of the resistors and the other end of the series of the resistors; and

a controlling terminal electronically connected to the microprocessor, such that the microprocessor drives the multiplexer to determine which one of the switching terminals is connected to the common terminal.

6. The battery tester as claimed in claim 1, wherein the variable loading unit has:

a programmable variable resistor having a controlling end electronically connected to the microprocessor; and

a switch connected between the programmable variable resistor and the detecting wire, and electronically connected to the microprocessor.

7. The battery tester as claimed in claim 1, wherein the variable loading unit has:

a programmable variable resistor having;

two ends respectively connected to the detecting wires; and

a controlling end electronically connected to the microprocessor;

a buffer electronically connected between the microprocessor and controlling end of the programmable variable resistor; and

a switch connected between one end of the programmable variable resistor and the detecting wire, and electronically connected to the microprocessor.

8. The battery tester as claimed in claim 3, wherein the detecting process has steps of:

(a) charging the battery to full capacity and then removing the battery from a charger;

(b) connecting the variable loading unit to the battery to discharge the battery and monitoring a discharging power;

(c) disconnecting the variable loading unit from the battery when the discharging power meets a power threshold;

(d) alternatively connecting the variable loading unit to the battery to detect multiple voltage values and current values of the battery; and

(e) completing the detecting waveform by the voltage values and current values.

9. The battery tester as claimed in claim 1, wherein the casing further comprises a display, a computer connector and an alarm.