Off-Grid System Installation
Other components needed for the off-grid system:
| Component | Image | Description |
|---|---|---|
| Solar Charge Controller |  |
The solar charge controller used in this project is a very popular, no-brand unit from China. However, any solar charge controller suitable for a 12 V system can be used. |
| 12V Solar Panel |  |
The solar panel must have a nominal voltage of 12 V and an open-circuit voltage (Voc) below 25 V. Under full sun conditions, it should be capable of delivering at least 0.3 A. The 10 W solar panel used in this project has dimensions of 43 x 20 cm. |
| 12V Battery |  |
A 12 V lead-acid battery, with a capacity of at least 7 Ah, must be used. Depending on battery quality, the battery should be replaced after 3–5 years of continuous use. |
| 12V Solenoid Valve |  |
A 12 V normally closed (NC) solenoid valve. Cheap valves should be replaced after 2–3 years of continuous use. |
| Metal Enclosure |  |
A 30 × 30 × 15 cm IP68-rated outdoor metal enclosure provides ample room to install and work on the components comfortably. |
Electrical Connections
The following diagram shows the electrical connections between the components of the off-grid irrigation system.
The Picapot controller, the solar charge controller, and the battery fit inside a 30 × 30 × 15 cm outdoor metal enclosure.
Three cables exit the enclosure: the first to the solar panel, the second to the solenoid valve, and an optional third to the 1-wire external sensor.
Personally, I prefer to use a single large cable gland (PG 13.5) through which all the cables pass. After every cable is in place and fixed to the metal plate with cable ties, fill the gland with neutral silicone (e.g., 704 silicone).
To avoid malfunctions, the solar panel should always be the last component to be connected and the first to be disconnected.
Plumbing Connections
Unless you have a dedicated water outlet for irrigation, the most common situation is having a single outdoor faucet that you want to keep while also adding a solenoid valve for the irrigation system. The diagram below shows how to connect both a faucet and a solenoid valve to the same water outlet.
