Solar Inverters

The inverter in your new solar system does the ‘hard work’ of the system, and in our view the quality of the inverter dictates the lifetime of your system. In the near term, the selection of the inverter is the most important component choice, and should be not forgotten when you assess the warranty of the solar systems you may be considering. Below, we detail the primary functions of a grid connected inverter, and provide some points to consider when purchasing a grid connect inverter.

Inverter Functions

Grid connected solar inverters don’t just convert direct current DC electricity to household AC power, they are now sophisticated microcomputers that track and analyse many aspects of solar system performance. These are the key duties of a modern grid connect inverter:

  • Inversion – The inverter converts DC electricity to AC electricity;
  • Grid Monitoring & Matching – The inverter monitors the grid, and replicates its key parameters of frequency & voltage curve.
  • Anti-islanding Protection – The inverter constantly monitors the grid, and should the grid go down, the inverter senses the change and shuts off immediately to protect utility workers;
  • Maximum Power Point Tracking (MPPT) – The inverter constantly monitors the performance of the solar array to ensure that the solar panels are operating at their best level for the given conditions (new to ‘off grid’ inverter-chargers, this MPPT function has long been a function of grid connect inverters);
  • Data capture & display – most inverters have a screen that allows for the display of data such as instantaneous power, daily energy production, and energy production over the lifetime of the inverter.

Points to consider

We recommend you consider the following points when deciding on a grid connect inverter:

  1. Reliability of the Inverter – is the inverter likely to spend time offline whilst waiting for repairs? Time is money here.
  2. Popularity of the Inverter – inverters from large manufacturers will have good availability of parts, and will be familiar to installers
  3. Warranty – how long is the warranty for, what does it cover, and is it necessary to send the inverter to USA, China etc
  4. Conversion Efficiency – How effective is the inverter at converting electricity from DC to AC?
  5. Temperature Range – Don’t make the mistake one large electricity company made selecting Japanese inverters only suitable for cold climates.

You may also like to consider micro-inverters and solar optimisers.