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Help to size an installation

In which case nenewables are they interesting ?

Many people hope to make savings on their energy bills by installing solar panels or a wind turbine at home. But renewables energies are rarely competitive with a national network (JIRAMA).

Renewables energies are useful and profitable in the case of using a generator in isolated site where the costs of operation and maintenance are extremely high.

For installations in the city, there are other solutions to avoid inconvenience due to frequent power cuts on the African continent that also protect equipment against over voltage and under voltage.

How to size you installation ?

Here are several steps to properly size your system :

  1. To estimate your energy consumption
  2. To know the sunshine in your future installation
  3. To calculate the power of the solar system you need
  4. To size converters
  5. To size batteries

How to optimize your solar return ? Click HERE !

How to estimate the energy consumption? 

The first step in any project is to quantify solar energy you need. It is from this amount of energy that you know how much power solar panels or wind will help you.

Follow this link and download a free energy balance sheet

This sheet is easy to complete, just put all your electrical appliances and ther wattage and operating time per day in hours.
The energy consumed by a device is the multiplication of these two data, you will get an amount of kWh/day. You must be as precise as possible to avoid over or under size your installation.

Here is an example :

Two 15W bulbs working 3 hours a day.

  • 2 bulbs x 15 Watt x 3h/day = 90Wh/day

One 50W TV operating 4hours a day

  • 1 TV x 50 Watt x 4h/day = 200Wh/day

The total daily consumption for these two devices is = 290Wh/day (200+90)

From this example, you can simply add the consumption of all you equipment and it's done !

If you have devices in direct current (DC), make a separate table because the calculation methods are not the same in DC (direct current) and in AC (Aleternating Current Type 220V, JIRAMA, EDF).

Now that you have your daily energy consymption, it is time to think about energy savings. Indeed, in solar or wind power systems, energy is not infinite unlike the energy that comes from your network.

More you will decrease your consumption, more the initial investment will be low.

Here are some examples of very efficient appliances that must be avoided.

  • Conditioning
  • Anything that contains a resistor like irons, ovens, electric stove, rice cooker, electric heaters, electric water heaters...

A little less greedy but that increase the bill anyway...

  • Anything that contains a motor like refrigerators, pumps, suppressors, appliances, vacuum cleaners.

As soon as we begin to evaluate the amount of energy we consume, we quickly realize the usefulness or the obligation to select the appliances that consume less.

Unless you have an unlimited budget !


Fortunately, many of these devices are not required or can be easily replaced by another energy such as gas for cooking or the sun to warm water.

So to reduce the amount of energy that will be needed per day, several strategies must be adopted :

  • Choose simple devices. For example, a chandelier with 12 bulbs, even economic, always consume more than normal lamp with one light bulb.
  • For general lighting, be wary of lampshades that mask too much light and put your spots where you need it.
  • Choose efficient receptor class A like light bulbs or LEDs for lighting.
  • If you are at the beginning of your project and you do not have the equipment, then it is better to buy DC appliances, for lighting you can put 12 volts. (Provided that the distances are not too long). Your convertor will less work and can also be smaller.


This is a lamp LED from 3 to 7W which mimics an incandescent bulb but consuming 10 to 15 times less.

The label "A" represents the most economical to the most greedy.

The goal is to achieve a balance between consumption and production.

You can now use your energy balance sheet to calculate the energy consumed per day to keep the design of your system.

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