Battery Charge Limiter and Calibration/Test Fixture

1. Battery Charge Limiter and Calibration/Test Fixture ECE 345 Senior Design Jeffrey J. Rodenkirch Professor: Gary Swenson TA: Mark Wiegert

2. Battery Charge Limiter and Calibration/Test Fixture • Battery charge limiter: • Battery gets fully charged • Battery stays charged • No damage to battery • Calibration/test fixture: • Calibrate, then test battery charge limiter

3. Objective • To design and build a battery charge limiter: • Specifications: • For 12 to 96 volt batteries • For up to 60 Amps • Minimize cost • To design and build a calibration/test fixture: • Calibrate • Test

4. Objective (cont.) • To develop CAD drawings of the battery charge limiter • To develop PCB files for the battery charge limiter

5. Original Design – Battery Charge Limiter

6. Original Design – Calibration/Test fixture

7. Project Build – Battery Charge Limiter • Battery charge limiter • MOSFET • Ideal resistor values

8. Project Build:Battery ChargeLimiter (cont.)

9. Project Build:Battery Charge Limiter (cont.)

10. Project Build:Battery ChargeLimiter (cont.)

11. Project Build – Battery Charge Limiter (cont.) • Files for the circuit board supplier: • Component Parts List • Manufacturing Notes • DXF drawing

12. Project Build – Battery Charge Limiter (cont.)

13. Project Build – Battery Charge Limiter (cont.) • Manufacturing Notes • Holes to plate • Copper thickness • Board thickness • References to files • Special instructions • Etc.

14. Project Build – Battery Charge Limiter (cont.)

15. Functional Tests – Battery Charge Limiter

16. Functional Tests – Battery Charge Limiter (cont.)

17. Project Build – Calibration/Test Fixture

18. Project Build – Calibration/Test Fixture (cont.)

19. Project Build – Calibration/Test Fixture (cont.)

20. Functional Tests – Calibration/Test Fixture • Calibration/test fixture: • The two voltmeter output: • Minimum and maximum • Digital circuitry and outputs • Used to calibrate and test the battery charge limiter.

21. Challenges and Successes • Battery charge limiter • EMI/RFI problem • Battery’s voltage was not oscillating • Used function generator to fix problem • Calibration/test fixture (original design) • Voltage comparators • Original – LM319 • Replacement – LM339 • Pursuing a new idea

22. Other Tests • Battery charge limiter • Heating and cooling • Small changes

23. Recommendations – Battery Charge Limiter • Replace R1 with a fixed regulator • Requires adequate Iout & large (Vin – Vout). • Voltage systems from 12 to 54 Volts or voltage systems from 24 to 120 Volts • Less inventory & meets most customer needs

24. Recommendations – Calibration/Test Fixture • During calibration eliminate battery • Consistency for mass production • Digital read-out of the MOSFET’s temperature during testing

25. Summary • Battery charge limiter does everything it was designed to do • Calibration/test fixture can be used easily and reliably to calibrate and test the battery charge limiter

26. Acknowledgements • The battery charge limiter was designed to meet specifications provided by Concorde Battery Corp. • Concorde Battery Corp. paid for all materials and parts for both the battery charge limiter and the calibration/test fixture