AC solar systems are easier to install and maintain, provide greater performance, safer and more reliable.

AC Solar systems out perform traditional DC solar systems in the area of energy harvest, reliability, safety and ease of upgrade.

AC Solar systems do away with dangerous high DC voltages which can cause fire or shock.

What is AC Solar?

Conventional direct current (DC) solar systems consist of a number of solar modules wired together in series configuration to create ‘strings’ of modules, with a combined output voltage typically between 200 and 600 volts DC. This is then fed into a single large inverter, which converts the voltage to 240 volts AC for connection to the electricity distribution system.

DC solar system have high DC voltages that are challenging to provide electrical protection.  Poor DC connections have caused roof fires.

 

Alternating current (AC) solar systems use micro inverters (typically one microinverter per solar panel) to convert the output of each solar panel directly to 240 volts AC. This eliminates the need to install DC cabling between modules or to install a large centralised inverter, and greatly simplifies the installation, monitoring and maintenance of the system. Microinverters provide all of the functionality of conventional string inverters – such as automatic disconnect and reconnect when the grid fails – and are required to conform to the same standards (including AS4777).

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The advantages of AC systems

Simplified system design, installation and maintenance

  • Installation is easier and up to 20% faster than for DC solar systems
  • Modules can be installed with differing orientations
  • Systems can be easily expanded by adding any number of additional AC Solar modules at any time.
  • Systems are wired with conventional AC cables – no specialised DC cabling required
  • No string sizes or DC voltage limitations to factor into the design.
  • Balance of system costs (enclosures, DC breakers etc.) are significantly reduced.
  • System commissioning and trouble-shooting is greatly simplified due to the data logging capabilities built into each module. Under-performing modules can be quickly identified and investigated.

Greater safety and reliability

  • Eliminates the string inverter as a single point of total system failure.
  • If a unit does fail it only affects the output of one module and not the whole system.
  • System data is available at a module level (as opposed to a string or overall level). Continuous monitoring of each individual module via an internet gateway enables prompt response to any shading problems or component failure.
  • No high voltage DC cabling on the roof.
  • No DC circuit breakers or fuses required.

Improved system performance

  • Each module is individually maximum power point tracked ensuring the maximum energy generation from every module installed.
  • Any shading that occurs only affects the output of the shaded module, not a complete string.
  • Reduced wiring losses compared to low voltage DC systems Increased energy production of up to 25% has been recorded

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Frequently asked questions

This page contains the answers to some commonly asked questions about AC Solar. If you have a question that is not answered here, please email us at info@acsolarwarehouse.com and we’ll do our best to answer it for you.

  • 1. Do AC Solar systems disconnect from the electricity network when the grid fails or is turned off?

    Microinverters are designed and tested to meet the same electrical and safety standards as conventional inverters and operate in a similar way. AC Solar modules turn off if the grid supply is lost or falls outside of preset limits, and reconnect several minutes after supply is restored.

  • 2. Are AC Solar Systems as safe as conventional solar systems?

    The inverters in AC Solar systems are required to meet the same electrical and safety standards as larger conventional inverters. In normal solar installations, DC voltages of up to 600 volts are common in the cables joining the individual modules and connecting the modules to the centralised inverter. During the day, these voltages exist even when the system is switched off at the main switchboard and can pose serious fire and personal safety hazards.

    Under fault conditions, a DC (Direct Current) arc can be difficult to extinguish. Special DC circuit breakers are required to be used and even these do not eliminate the risk of fire caused by a fault within the DC wiring.

    AC Solar systems do not pose the same risk because there are no significant DC voltages present within the system.

    AC Solar systems are connected to the main switchboard via a conventional circuit breaker and their wiring poses no more risk than normal household electrical wiring. Furthermore, the cables connecting the panels to the main switchboard are de-energised instantly when the mains fail or the isolating switch on the main switchboard is operated thus removing any risk of shock to residents or emergency services personnel.

  • 3. Do microinverters and AC modules need to be earthed?

    Yes, microinverters and AC modules need to be earthed in accordance with AS3000 and AS5033. This is, however, usually a simple process. An earth conductor is typically run from the main switchboard (or sub board) along with active and neutral conductors and carried through to each AC module via the module connection plug. From the connection plug, the earth is connected to both the microinverter input and the module frame, ensuring the entire array is securely earthed.

    Where the microinverter is mounted separately to the module (i.e. on the rail beneath the module), an earthing washer should be used between the microinverter and the rail to ensure that the earthed frame of the microinverter provides an acceptable earth connection to the rail. Earth washers are also required between the modules and the rails. You should always refer to the technical specifications and installation instructions provided by the manufacturer of the equipment you are installing to make sure appropriate earthing is achieved in accordance with the required standards.

    We are happy to answer any questions you may have regarding the correct installation of any equipment purchased from the AC Solar Warehouse.

  • 4. What length warranties do AC Module and microinverter manufacturers offer?

    Solar module warranties are generally unaffected by their use as an AC module. You should seek confirmation of this from your solar module supplier.

    Microinverters warranties vary from 10 to 25 years depending on the manufacturer.

  • 5. How does the data logging / system monitoring work?

    Most AC solar module and microinverter manufacturers incorporate comprehensive data logging features in their products. Data is normally transmitted either wirelessly or via a power line carrier (PLC) signal from each individual module to an Internet Gateway device mounted in a convenient location within the home or business. This device is connected to the customer’s broadband connection – either via LAN cable or wirelessly. If the homeowner accesses the internet via a USB dongle, an inexpensive wireless router may be required to be installed in order for the Internet Gateway to be connected into the system. The Internet Gateway aggregates the data from the individual solar modules and sends it to a data warehouse on the internet.

    The installer and the customer can access the data via a password protected website 24/7 to monitor the performance of the system. Some equipment manufacturers have the facility to send the installer and/or customer an email if the operation of the system falls outside of preset parameters. This makes new shading or solar module failures quick and easy to identify and troubleshoot.

  • 6. Can AC Solar systems be installed at sites where there is no internet connection available?

    If no internet connection is available close by the site of the installation, then the remote monitoring functionality will obviously not be able to be implemented.

    It is still possible to install a microinverter system without an internet connection – only the remote monitoring function will be affected.

    Some microinverter Internet Gateways provide a local indication of the status of the AC Solar system which can be useful if the remote monitoring function is not going to be implemented. For further information about the best products to use in these situations contact the team at at the AC Solar Warehouse.

  • 7. How much do AC Solar systems cost, compared to conventional DC systems?

    The total equipment cost of AC Solar systems is currently around 10% – 25% more than that of a similar quality DC system. This additional cost is offset by savings in the installation of the system, particularly savings from not having to install DC cables, isolators and circuit breakers and not having to run the DC cables in heavy duty conduit in the roof space. Because of the increased energy yield over the full life of the system the overall return on investment for AC Solar systems can be substantially more attractive than for DC systems.

Document library

Welcome to our document library. The library contains a list of technical and marketing material available to our customers to assist in installing and marketing AC Solar systems. To request a full copy of these documents, call us or send us an email at info@acsolarwarehouse.com

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Contact

  • Email

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  • Phone

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  • Queensland 4870

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  • Queensland 4870

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