Off-grid Systems

When a location is not connected to the electrical grid, it is considered off-grid. Gasoline-powered generators are an option for providing electricity, but they are noisy, polluting, and expensive to run for long periods of time.

A popular renewable option for off-grid sites is electricity from solar photovoltaic (PV) panels. It is easy to install, quiet, and requires little maintenance.

The high initial cost is usually offset over the years by fuel savings.

1. The solar panels convert sunlight into electricity.
2. The solar charge controller uses the electric current from the panels to charge the batteries properly
3. The batteries store the energy for later use
4. The inverter converts the low voltage (12 V) into domestic voltage (120 V)
5. The battery charger, plugged into a generator, allows to charge the batteries when the sun has not been shining for a few days.
6. A fuse block distributes the current to the 12 V appliances…
7. …like a 12 V fridge.
8. To protect the batteries from deep discharge, a protection is strongly recommended
9. Circuit breakers protect the equipment and even the cables against short circuits and over-voltage
10. High power inverters require large cables and fuses to carry the necessary current.

Small wind turbines seem like a good idea for small off-grid installations, since the wind seems so powerful. Why don't we see more of them?

The wind gets stronger and more consistent the higher we go into the air. This means we need tall towers, which are expensive to build. Wind turbines need to be protected from storms and, because they contain moving parts, they require maintenance. For large wind turbines, large towers, the protection and maintenance is worth it, but for small ones often is not. In real life, small wind turbines rarely work as well as expected.

Here is the recording of our webinar on small solar PV installations :

Medium size installations require more analysis, in order not to over- or under-size the components.

• Guide to renewable energy at the cottage (RNCRNQ) (en)
• Youtube channel: 12 V Planet (en) on 12 V electrical systems.

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