1. 02/06/031 State of the Art Battery Charger Team: Richard Musumhi Bo Bo Oo Pascal Openshaw Chris Privitere Client: Senior Design 2/6/2003 Team May 03-05 Advisors: Dr. John Lamont Dr. Richard Patterson

2. 02/06/031 Presentation Outline Overview – Assumptions, limitations Activities – Research, design Time and money – Budget, personnel Conclusion – Additional work, summary

3. 02/06/031 Definitions PIC – Peripheral Interface Controller Smart device – Able to make decisions based on inputs NiCad, NiMH – Most common rechargeable batteries on the market, Nickel Cadmium and Nickel Metal Hydride

4. 02/06/031 Project Overview What is a battery charger? – Takes discharged batteries and restores their chemical properties using an alternate source of power, such as the sun or a wall outlet. The need for a new charger – None of the chargers on the market have as full a feature set as the one that our group has designed.

5. 02/06/031 Problem Statement - Needs Need a battery charger that is: Small Portable American, European, or car powered Charge 1-4 AA/AAA NiCad or NiMH batteries in 1-2 hours

6. 02/06/031 Problem Statement - Tasks We need to: 1. Convert the power 2. Charge the battery 3. Sense when to stop charging the batteries 4. Control the system

7. 02/06/031 Problem 1: Power Transform External power – 12V – Commercial 120V and 220V wall adapter – Commercial 12V car adapter Internal power – DC to DC converter to 6V and 3V – User does not notice

8. 02/06/031 Problem 2: Charging control Layout Digital-to-Analog Converter Peripheral Interface Controller Current controllers

9. 02/06/031 Problem 3: Stop charging? NiCad: A voltage drop NiMH: A temperature rise Safeguards – Combine both – Max timer – Code checks

10. 02/06/031 Problem 4: Control the System Choices – Pre-built microchip – Microprocessor State machine – The group decided to use a PIC microcontroller with appropriate code and control.

11. 02/06/031 The Charger Working final product: ugly, based on breadboard with plenty of wires Commercial final product: attractive, cool design, portable.

12. 02/06/031 Operating Environment Used indoors or in a vehicle Can not be used in extreme heat, cold, or wet conditions

13. 02/06/031 Intended Users and Uses Designed for the frequent picture taker or other user of electronic equipment Batteries run out frequently Charger will charge the batteries quickly without damaging them

14. 02/06/031 Assumptions Power sources are 120V/220V AC or 12V DC Charger will charge 1-4 batteries Charger is only needed indoors or in a vehicle

15. 02/06/031 Limitations $100 budget The batteries used do not have “smart” capabilities. The charger cannot draw so much current that it would kill a car battery.

16. 02/06/031 End-Product Description Battery charger that can be used on 120V or 220V AC and 12V DC Can charge 1-4 batteries in 1-2 hours Portable and easy to use

17. 02/06/031 Project Activities Definition Research Design Implementation Testing Final Product, yay!

18. 02/06/031 Presentation Accomplishments Design Spec80% Components bought 70% Software programming 0% Implementation 0% Testing 0%

19. 02/06/031 Approach considered and used PLAN A Use a microchip MAX 713 Requires no programming Batteries can only be charged in series Minimum of two batteries Fewer options

20. 02/06/031 PLAN B Use microchip DS 2770 Charges exactly 3 NIMH cells at a time Capable of charging Lith-Ion battery Temperature terminated Expensive

21. 02/06/031 PLAN C PIC microcontroller Voltage and temperature sensors Software programming for greater flexibility One battery at a time More expensive

22. 02/06/031 Decisions, decisions Plan C wins The PIC microcontroller provided the most flexibility and options to the team.

23. 02/06/031 Definition Activities Most important requirement – Should be able to operate on 120v ac/60Hz, 12v DC, 220v ac/50Hz. Charge AA/AAA. Discharge/conditioning Trickle charge Portable

24. 02/06/031 Design Activities External transformer – Convert 120/220V to the 12V Internal transformer – Change 12V to internal levels needed Circuit – Various digital to analog converters, current controllers, and sensors Software – State machine to start and terminate fast battery charging

25. 02/06/031 Research Activities Research Activities Handbook of Batteries,third edition.David Linden and Thomas B. Reddy,McGraw-Hill,New York 2002 John Oeler,john.oeler@dalsemi.com For Dallas technical support

26. 02/06/031 Implementation Activities Purchasing – Most components purchased Circuit board setup Software testing Software upload – Final product should function on its own without any glitches

27. 02/06/031 Testing Activities Digital to Analog accuracy Current control accuracy Detecting voltage and temperature changes properly Properly charge 10 batteries No overheating

28. 02/06/031 Testing Activities continued Detect insertion/removal of a battery causing circuit to be reset. Final product functionality

29. 02/06/031 Resources - Personnel 361 hrs448 hrsTotal 87 hrs121 hrsChris Privitere 98 hrs128 hrsPascal Openshaw 91 hrs99 hrsBo Bo Oo 85 hrs100 hrsRichard Musumhi RevisedOriginal

30. 02/06/031 Resources - Financial $73.00$89.00Total $24.00 Batteries $44.50$59.00Digital IC’s and adapters $4.50$6.00Microprocessor RevisedOriginal

31. 02/06/031

32. 1 Risks & Risk Managements The loss of team member – Document work Microprocessor might not be useful – Alternatives Delays in product shipments, damage of parts – Purchase extras and in advance

33. 02/06/031 Lessons learned Start early Communication is important Manage time efficiently Good documentation Get help from faculty advisors

34. 02/06/031 Additional work Create a generic design that can be commercialized Optimize the cost for mass production Increase capabilities

35. 02/06/031 Commercialization Device cost - PIC: $4.50 - LEDs: 1.00 - battery monitors: 7.00 - LED driver: 4.00 - transc amps: 1.00 - 12 V wall adapter $10.00 - 12 V car adapter 7.00 - plug receivers 1.00 - DC to DC converter 6.00 - DAC 7.50 TOTAL = 49.00

36. 02/06/031 Commercialization cont. Estimated total cost, no bulk – $ 49 Distributor price – $ 70 Retail Price – $ 90

37. 02/06/031 Project Summary State-of-the-art battery charger – Can be used worldwide – Easy to use – Portable – 1 year of development

38. 02/06/031 State of the Art Battery Charger Team: Richard Musumhi Bo Bo Oo Pascal Openshaw Chris Privitere Client: Senior Design 2/6/2003 Team May 03-05 Advisors: Dr. John Lamont Dr. Richard Patterson Questions?