January 7, 2015
solar-panel-roof

What Type of System to Install?

There are many types of systems that’s confusing you, we know! This article may help you choose the right system for you! So, let’s go step by step with our completed systems list:

Off-Grid Systems:

There are two types of off-grid systems, first one is an off grid system that is only compatible with DC loads (only). This system consists of:

  • PV array
  • Mounting Structure
  • Battery bank
  • Charge controller
  • DC Loads
  • Required electrical safety gear (breakers, fuses, disconnects, etc.)

 

This system is good with very few loads like, small RVs, street lights, and sail boats. It also has a reduced cost for the absence of the inverter.

The second off-grid system is a system that is with AC loads. This system includes:

  • PV array
  • Mounting structure
  • Battery Bank
  • Charge controller or Inverter/Charger
  • Inverter or Inverter/Charger
  • Required electrical safety gear (breakers, fuses, disconnects, etc.)

 

We know that the PV array produce power in Direct-Current (DC), when having AC loads instead of DC, you will always need an inverter. Off-grid systems with ac loads is a great system for any type of AC load, from a single load to a large off-grid project, all that matters would be the system sizing in this case. “Inverter/Charger” this may confuse you so let me make it clear for you an Inverter/ Charger can function as both an inverter and as a battery charger. Note that off-grid inverters are not designed to sell power back to a utility grid service, but have an internal battery charger that can utilize AC electricity from a generator or the utility and convert it to DC electricity to charge the battery bank.

Grid-Tied Systems:

Also known as Grid-Connected systems, these systems operate parallel with the utility grid. In a grid-tied system just like any PV array does, they produce DC power. This DC power then needs to be inverted to AC power to send to the building’s electrical panel to supply power. To be able to make this power change, an inverter is required. Grid-tied systems also require the installation of a special meter by the utility, and during daytime any power in excess of the load is sold back to the utility in the form of credits! Which means that if your system produces more power than you use, it sells rest of the power to the utility, and if your PV system produces less power than you need, than you get the power from the utility company (this happens mostly night time). You would use this system home or business.

This system includes:

  • PV array
  • Mounting structure
  • Inverter
  • Required electrical safety gear (breakers, fuses, disconnects, etc.)

Grid-tied with Battery Backup:

Also known as Grid-Interactive system. Grid-interactive system is just like grid-tied system, it is connected to the utility and uses inverted PV power. Unlike grid-tied, grid-interactive systems can provide independent power. As the name gives it up, this system includes a battery bank. The backup battery is charged from both the panels and the grid. This system can supply power during outages and after sundown.

This system includes:

  • PV array
  • Mounting structures
  • Battery bank
  • Charge controller
  • Inverter
  • Required electrical safety gear (breakers, fuses, disconnects, etc.)

Note that many people consider grid-tied battery backup system as a hybrid system.

Hybrid Systems:

There are many different types of hybrid systems. Why? Because hybrid system is a grid-interactive system used with other energy sources, such as wind turbines or generators.

This system includes:

  • PV array
  • Mounting structures
  • Battery bank
  • Charge controller
  • Inverter
  • Required electrical safety gear (breakers, fuses, disconnects, etc.)
  • Other energy sources

 

  Grid-Tied Off-Grid Grid-Tied Battery Backup
PROS
  • Lowest initial cost
  • Simplest to install
  • Lowest ongoing maintenance cost
  • Most efficient
  • You can start small and add on to it
  • Independent from the utility grid
  • No need to deal with the utility company
  • Really encourages conservation and efficiency in the use of electricity
  • Provides backup power
  • Has some advantages of both systems
CONS
  • If the grid is down, no power
  • Access to the utility grid required
  • Higher initial Cost
  • Higher ongoing time and cost
  • System must be large enough to supply your full power needs
  • You are the power company, you are responsible for everything
  • Has a battery system that is more costly
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