There are a lot of components in the circuit that can reduce the solar electric system’s efficiency, such as batteries, resistance, and inverters. These factors need to be taken into account when computing the solar electric system’s requirements.

Calculating inefficiencies

Charge Cycle Efficiency (CCE) numbers can be obtained from battery manufacturers, but generally, most batteries that are of industrial or traction quality give 95 percent efficiency. It is unfortunate that batteries do not discharge the energy stored at 100 percent of their charging rate.

The battery’s CCE notes the percentage of available energy compared to the energy amount used for charging.

If you are going to be using an inverter, the inverter inefficiency will need to be factored into the system. This figure can be obtained from the inverter’s manufacturers. In general, an inverter usually runs at 90 percent efficiency.

With the usage of batteries, only 5 percent needs to be added to account for the CCE, based on the total energy requirement. Add that to the value determined in the power analysis.

Knowing when you will be using your solar electric system the most is an important factor. For a year-round home, your system will need to generate sufficient electricity even in the depths of winter if you wish to have power throughout the season. Whereas for a holiday home, you may only need to concern yourself primarily with the electricity you will need for the summer, spring and autumn seasons, with minor usage in the winter.

For the latter purposes, your solar electric system will not need to work to full capacity during the cold season, it must only charge the batteries sufficiently for occasional weekend visits during the winter. When the home is left vacant, the batteries will be left recharging by the solar array. To ease electricity usage, a standby generator can be a big plus for providing extra electricity during the winter, even if it is a small unit. This can also be useful for boosting the battery charge.