Balance of system

components required in photo-voltaic technology..i.e. batteries, inverters, mounting structures etc.

1. BALANCE OF SYSTEM

2. What is BOS ? Everything in the “gap” between PV modules & the Grid.

3. bos

4. BOS The balance of system or BOS encompasses all components of a photovoltaic system other than the photovoltaic panels. This includes wiring, switches, a mounting system, one or many solar inverters, a battery bank and battery charger. For ground-mount systems, land is sometimes included as part of the BOS as well.

5. Components of BOS Power Electronics Inverters batteries Mounting Structures Racking - Fixed tilt Tracking systems Single axis Dual axis Cables and connectors Weather measurement

6. Charge regulators Control the electricity generated by a solar module

7. Charge regulators Charge regulators are the link between the PV modules and battery. Control the amount of charge flowing in and out of a battery Protect the battery from overcharge or excessive discharge. High temperatures tend to reduce battery life because they accelerate corrosion and self-discharge. The resistance of lead-acid batteries to freezing is reduced when they are discharged, so batteries should be kept charged when they are left in low temperature conditions during the winter. Single module need charge controller of between 4A – 6A & larger arrays may need charge controller of 40A or even more

8. Battery Store electric energy

9. Battery The simplest means of electricity storage is to use the electric rechargeable batteries, especially when PV modules produce the DC current required for charging the batteries. Batteries store the electrical energy generated by the modules during sunny periods, and deliver it whenever the modules cannot supply power or cloudy days. Most of batteries used in PV systems are lead-acid batteries. In some applications, for example when used in locations with extreme climate conditions or where high reliability is essential, nickel-cadmium batteries are used.

10. Battery The following factors should be considered when choosing a battery for a PV application: Operating temperature range (e.g.: -15°C to 50°C) Self discharge rate (% per month) Cycle life to 80% depth of discharge (DOD) Capacity (Ah) at 10 hr & 100 hr rates (C10 & C100) Robustness for transport to site Resistance to overcharging Cost battery efficiency for most PV application is 85%

11. Inverters DC to AC Converter

12. The inverter's main functions are: transformation of DC electricity into AC, wave shaping of the output AC electricity. The most important features of an inverter for PV applications are its reliability and its efficiency characteristics. They are designed to operate a PV system continuously near its maximum power point . Inverters have efficiencies ranging from 85% to 95% for most PV application. Inverters

13. Mounting Structures Main support of module

14. Mounting structures The structuring that supports the modules Typically aluminum, galvanised iron Should be corrosion resistant Choose depending on soil, wind and weather conditions! Overwhelming majority : Fixed tilt Rare: Single or double-axis trackers

15. Mounting structures Fixed Tilt Single Axis Double Axis

16. Fixed tilt Source: Schletter

17. Tracking systems Type of Tracking systems A. Manually operated B. Motor operated Single Axis Dual axis

18. Manually operated Available in both single axis and dual axis modes

19. Motor operated Source: Linak AS

20. Motor operated Single axis Dual axis

21. Cable and Connectors The electricity carriers

22. Weather measurement Energy output directly related to ambient conditions like Amount of sunlight(Irradiation) PV Module temperature Ambient temperature

23. Irradiation sensors

24. Module and ambient temperature meaurement