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  • What are SOLAR CELLS ?

Thin wafers of silicon ( similar to computer chips, but much bigger), which convert SUNLIGHT ENERGY into Electric CURRENT .

  • What is a SPV MODULE ?

Solar Cells connected together form a MODULE. 36 Cells connected together in a module generate enough voltage to charge 12 V Batteries. The module converts) SUNLIGHT into DIRECT CURRENT (DC) Electricity .

  • What is a MODULE made out of?

Individual silicon cells are connected electrically and placed between layers of protective materials. This is then heat laminated to a protective glass sheet. Anodised Aluminum frame surrounds the glass.

  • Are Modules available in different power Yes, the power ratings are measured in ratings ?

Watts. For example a 12 V 30 Wp module operates on 12 V and has a power rating of 30 Wp. In the market currently, modules are generally available from 2 W to 75 Wp ratings.

  • What is a Solar Array ?

Based on the total power output required, / modules connected in series or parallel, constitute SOLAR ARRAY. For example, for a DC output system for say 500 Wp, the array might constitute 1 0 MODULES of 50 WP each connected together..

  • What is the meaning of' 'LOAD'' ?

LOAD constitutes the total electricity demand for all your lights, fans etc. .This is measured in watt hours or Kilowatt hours per day.

  • How can 1calculate my ''LOAD'' ?

You must know the power rating of each of the applications like light, fans, refrigerator etc. that you wish to use and the average usage hours per day for each of the items. This put together will decide the LOAD. For example if you wish to have 5 Nos. 50 W bulbs running for 10 hrs per day, then the load is 5 x 60 x 10 = 3000 WH or 3 KWH per day .

  • What is a SOLAR SYSTEM ?

A simple Solar System for DC lights and appliances will comprise a SOLAR PV MODULE, a REGULATOR (or charge controller), a BATTERY and your LOAD. These components connected together form a SOLAR SYSTEM.

  • How is the generated power stored ?

The power generated by the PV module is stored in a battery bank, Depending on the system size No. of batteries could be one or more connected in series or parallel to form, the BATTERY BANK.

  • What kind of Battery should be used ?

Batteries designed for repeated cycling , should be used. Car batteries are not suitable for SOLAR applications and should not be used. Batteries come in different sizes depending on the system size. For example a 12 V 40 AH (at C 10 charging rate ) battery is operated on 12 V and has a capacity of 40 amp hour.

  • What is Cycling ?

Cycling is the partial discharge of a battery and then recharging it to full charge.

  • When does cycling occur ?

During nights, when the battery is discharged, without any solar charge getting into the battery, cycling will occur .During the day when SUNLIGHT is available the solar modules will recharge the batteries.

  • What is the meaning of self discharge ?

The battery when not working tends to discharge on its own which is called self discharge. The battery should be made in , such a way that the self discharge is minimal.

  • What is the function of a regulator ?

Overcharging or undercharging pf the battery could reduce its life. The regulator controls the amount of charge going into the battery from the solar module.

  • Is it necessary to have a regulator always ?

Some Solar modules are self regulating. This means the module stops charging the battery when it is fully charged. In this case the regulator is not used. However , this is generally for small systems using one or two modules only

  • What should be the size of the module / solar The size / capacity of the Solar module or Array ?

array would depend on the load required and the ambient conditions at the site of the installation. The size of the array should be such that it generates adequate power to take care of the load requirements. Consult a s stem supplier in this regard.

  • What should be the size of my battery bank ?

The size of the battery bank will depend on several factors, including the type of system being installed, the ambient conditions at site etc. Consult a s stem system supplier in this regard.

  • Are special Cables required ?

To avoid voltage drop, normally cables of larger diameter are used, compared to normal size of cables for house wiring for conventional electricity .

  • Can 220 V / 230 V AC appliances be used ?

Yes, by installing an inverter into the system, which is designed to convert the DC power to 220 / 230 V AC power.

  • Can both DC and AC a appliances be used ?

Yes stems can be designed accordingly.

  • Are Solar products suitably guaranteed ?

Solar modules have a life of 20 / 25 years and are generally guaranteed for 1 0 years. Battery , if well designed, can have a life of 5 -7 years. In some cases the battery is guaranteed for 5 years. The total systems are generally guaranteed for 1 or 2 ears.

  • Can the system be expanded at a later date ?

Solar systems are quite modular in nature. They can be expanded as and when required by adding solar modules and battery bank. A higher size regulator may be required in some cases.

  • Who will install the Solar system ?

For small systems, an installation guide, operation and maintenance manual are generally provided. But it is better if the installation and commissioning is left to the suppliers who have trained technicians to do W'' the job. In the case of large systems or AC systems, dealing with high voltages could be dangerous. Only licensed technicians of the supplier should be entrusted with the .ob.

  • What would a typical system cost ?

System cost mainly depends on appliances used . IT would varies from system to system. However a solar PV combined of 2 nos 10wP CFL, one 40wP module, one 21 Ah batteries, charge controller and accessories present cost might be around BDT 17 thousand taka. Furthermore you could able to design your own system by clicking here.