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Off-grid System
The 5 Main Parts Of An Off-Grid System
- Battery Inverter/charger or Multi-mode hy brid inverter
- Solar inverter (AC) or MPPT Solar charge controllers (DC)
- Battery bank
- Solar panels
- Generator (Optional)
Off-grid system types - AC or DC-coupled
Off-grid systems are built using either AC or DC-coupled power sources. AC-coupled generation sources include common solar inverters, wind turbines or backup generators (gen-sets), while DC-coupled sources include MPPT solar charge controllers or micro-hydro systems.
Whether a system is AC or DC-coupled is generally based on the size of the system. Most small-scale systems are DC-coupled and use efficient MPPT solar charge controllers. Larger off-grid systems can be either AC or DC-coupled depending on the type of off-grid inverter-charger used, and compatibility with different solar inverters (AC) or solar charge controllers (DC). Most modern inverter-chargers can be both AC and DC-coupled, which creates a very secure, flexible power system with multiple charging options and can enable black-start operation if the main inverter shuts down, the backup generator fails or the batteries are depleted.
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Basic layout of a DC coupled off-grid system - The most versatile and modular off-grid configuration
Small DIY Off-Grid Solar Systems
Small-scale off-grid solar systems and DIY systems used on caravans, boats, small homes and cabins use MPPT solar charge controllers, also known as solar regulators, which are connected between the solar panel/s and battery. The job of the charge controller is to ensure the battery is charged correctly and more importantly, not overcharged. Most small 12V/24V solar charge controllers also have load output terminals which are often used for simple DC lighting circuits. In small DIY systems, simple ‘plug-in’ style inverters are used to provide 240V or 120V AC power. These are available in many different sizes, from tiny 150W inverters up to 3000W or higher.
Note: Small-scale, low-voltage systems can still cause damage or serious injury if not installed correctly - we recommend all systems are installed by a trained, licensed solar or electrical professional.
Small scale off-grid system with a single MPPT solar charge controller and small battery inverter.
DC-coupled solar charge controllers have been around for decades and are available in two main types, PWM and MPPT. Learn more about solar charge controllers here, plus how to size small-scale off-grid solar systems correctly. More powerful MPPT Solar charge controllers up to 100A are used on larger scale off-grid solar power systems. These are a very efficient and reliable way of charging and managing high-capacity lithium or lead-acid battery systems.