Frequently Asked Questions - FAQs

1. What is solar Photovoltaic (Solar PV)?
Photovoltaic is term formed by a combination of two Greek words: Photo, meaning sun-light and Voltaic, meaning electricity. Solar Photovoltaic therefore, refers to a technology whereby sun-light is converted into electricity.

2. How is sunlight converted into useful electricity?
Solar modules convert sunlight into electricity, which is then stored as a charge in solar batteries during the day time. Appliances such as lights, radio, TV sets, etc can then be powered by stored energy at anytime and even at night when there is no sunshine.

During charging process a regulator (sometimes called charge controller) is required in order to avoid overcharging and over discharging of batteries that might cause damage to batteries.
Some appliances such as color TV might be powered by a solar system after converting Power from DC to AC, in this case an inverter is required.

In addition to this, accessories such as cables and other accessories are required in order to interconnect the main components so as to build up a complete solar electric system.

3. What is a Solar Electric System?
A solar electric system refers to a configuration (a combination) of different components explained above, which are connected together in order to deliver a specific energy service.

4. What can solar electricity do for us?
Electricity obtain from solar system can be used for the following applications:

• Lighting
• Powering radio, radio cassettes
• Television
• Charging mobile phone
• Two way radio communication (HF Radio)
• Refrigerator
• Water pumping

NB: There are many other applications but these are very common ones.

5. What solar electricity cannot do?
Use of Solar PV technology is not economical for high energy consuming appliances such as: electric cookers, iron and three-phase machines. In this case you are advised to use other sources of energy like grid electricity and generators.

6. What happens if there is no sunshine (i.e during cloudy period)?
Before you buy a solar system you are advised to consult a competent technician, who will specify the sizes of required equipment that can meet your energy needs. If this is done, a well designed system should have enough storage of charge in batteries that can fulfill your electricity needs during the cloudy period. That means performance of your system will not be affected during this period. Example: In tropical countries, a system can be specified to deliver electricity services for three consecutive days in absence of sun shine. The exact number of days will depend on your geographical location and weather condition.

7. Can I use automotive batteries in a solar system?
Automotive batteries are not recommended because they are designed to deliver high currents for a short period of time, whereas solar batteries are supposed to deliver low current for longer period of time. If a car batteries is used it will not last as long as solar batteries. Car batteries can only be used as a last resource, incase solar batteries are not available. But again it is important to consult a skilled person for further advice on this.

8. Can I use similar lights as those used for grid electricity?
Yes, light for conventional electricity can be used. In this case you need a device called an inverter. Solar module generate Direct Current (DC) electricity only which should be converted into Alternating Current (AC) electricity by the use of an inverter in order to power lamps. However this approach is not recommended as much energy is wasted during conversion process. It is therefore recommended to use DC lamps, which do not need use of an inverter.

9. I have already done a wiring for the use of a generator in my house: Can I use same wiring for a PV system?
Wiring for generators involve use of small sizes of wires (normally 2.5mm2 or less) where as for solar system bigger sizes (not less than 2.5mm2) are required. Such wiring should be repeated with bigger sizes of wires by a skilled solar technician. Not necessary that all electrical technicians can install quality and reliable solar system for you.

10. How much does a solar system cost?
Cost of a solar system will depend on energy demand of specific system user. Energy demand is determined by power consumptions of appliances to be used in your system and duration(hours) you use them every day. That calls for skilled person who can determine size of you system components and therefore your system costs. Here are some typical examples of system costs. Note that system prices may differ for different dealers.

11. How long will a solar system last?
A solar module will last for more than 20 years, a charge controller for 10 years, lights for 7 years (tubes might be replaced after 2 years), batteries for 3 years and other accessories for 20 years.

12. Why use a solar system and not a petrol generator?
Solar system’s major investment is done once and maintenance costs are not significant as there are no any moving part. Petrol generators might have lower initial investment as compared to that of a solar system but it requires high operation costs including fuel, repair and maintenance. If costs of the two are compared over a period of their lifetime the cost of running a petrol generator overweighs that of a solar system. A generator is replaced after 2-3 years.

13. Where can I buy solar systems?

• Zara Solar Ltd.
  P. O. Box 110, Mwanza nearby Toto store, opposite Ijumaa Mosque
  Tel: 028 2502337 or 0744 487183,
  Fax: 028 2502910
• AOL Technology Ltd,
  Box 10467, Mwanza, Mitimirefu Street, Mohamed Trans Bus Building, 1st Floor
  Tel: 0741 244835, 0748 450769
• Tunakopesha Ltd. Box 10189, Mwanza City, Makongoro Road
  Tel. 028 2502444 or 0744 810094,
  Fax 028 2500442
• Intraprofession East Africa Ltd.
  P. O. Box 315, Sengerema, nearly KKKT, Sengerema Sec. Road
  Tel/Fax: 028 2590246, (0744 844957, 0745 340682, 0745 774506)
• Rasik General Merchandise
  Nansio-Ukerewe
  Tel: 028 2515024
• Mona Mwaza Electrical and Electronics,
  Mwanza,
  Tel: 0744 487183
• Umeme Solar Investment
  Box 264, Geita Bus Stand
  Tel: 0744 454484, 0748 816537