1. Lecture 28 October 30, 2013

2. Stand Alone PV

3. San Luis Valley Solar Data (09/11/2010) Good Day [1] 3

4. San Luis Valley Solar Data (09/12/2010) Bad Day [1] 4

5. Intermittent Wind Generation 5 5

6. Battery

7. Battery Equivalent Circuits

9. Lead Acid Battery

10. Battery Charge Discharge

11. Household Loads

12. Household Loads.

13. Electronic Loads

14. Battery Types Energy Density.

15. NaS Batteries For Grid 6h at 1MW 1 Operating temperature 300 to 350 o C

16. NaS Battery Characteristics

17. Picture NaS Battery

18. Present Value

19. Levelized Costs

20. Nickel Metal Hydride

21. Vanadium Redox Flow Battery

22. Picture VRB System

23. Present Value $/kw VRX

24. Levelized Costs

25. Zn Air Battery

26. Zinc-Air Battery Prototype

27. Zinc – Air Cell

28. Present Value

29. Levelized Costs

30. Li Ion Battery

32. Types of Li Ion Cells

33. Big System

34. Smaller System

35. Home Li Ion

36. Present Value Li Ion

37. Levelized Costs Li Ion

38. Li Ion Charge, Discharge Curves

39. Internal Resistance Li Ion Battery

40. Lead Acid Batteries

41. 1 MW Lead Acid Battery

42. Big System

43. Present Value $/kW and $/kWh Lead Acid

44. Levelized Costs Lead Acid

46. Some Limits On Batteries 1. Depth of Discharge. A. Car Batteries limits to 25% Life 10yr – At 50% cut life in half. Strengthen with Ca B. For solar cells need 50 to 80% This means thicker electrodes bigger space between electrodes. Sb C. Over charging leads to H 2 O→ 2H 2 +O 2 D. Capacity depends on rate of charging and discharging. E. Temperature dependence lower capacity at low temperatures

47. State of Charge 1. Internal resistance increases as the battery is discharged or with state of charge 2. This makes it hard to calculate watt hours. 3. Change to ampere hours and P= Vx I 4. Specify in C= Ampere hour capacity – C/20 means capacity for full discharge over 20hr.

48. Temperature Dependence of Lead Acid Battery

49. Deep Cycle Lead Acid Batteries

50. Rates of Charge and Discharge Change Capacity and Life

51. Series Parallel Connections

52. Battery Connections

53. Limiting Voltage for Current of 100 Amps

54. Hours of System Availability

55. Solar Cell to Battery Direct

56. Battery Charging

57. Typical Derating Chain

58. An Off Grid System

60. Diesel Backup Efficiency