Off-Grid Solar System: Inverter, Charge Controllers, etc

Just wanted to get a quick post up covering the core components of our off-grid system – by core components I am referring to the inverter and it’s accessories such as the charge controllers, auto generator starter, and so on.

For a bit of a preamble: the basic premise of an off-grid system is that you have a battery bank to draw on (charged from either the solar array or the generator), and connected to the battery bank is a pure sine wave inverter (MSW or modified sine wave inverters are available, and cheaper, but they produce lackluster power that doesn’t run all appliances well) which is responsible for converting the battery bank power (48VDC) to AC power (120/240VAC) to run our house.

Selecting an inverter is based on a number of factors – budget probably being foremost, but our selection criteria also included the following, listed roughly by importance:

  • Continuous power supply
  • Surge power supply
  • Integrated accessories such as charge controllers, auto generator start, and network monitoring
  • Reliability ratings, reputation of manufacturer (availability of repair parts)
  • Ability to “stack” inverters for possible future expansion

To satisfy the above criteria we considered Magnum Energy 4000W inverters, and also the Xantrex 6000W inverters.  In the end we chose the Xantrex 6000W inverter as it was most suited to meeting our current and future needs.  While the Magnum inverters are less expensive, we would have needed to start off with two 4000W inverters as I don’t think we would be able to get by with just 4000W continuous load.  Furthermore, the Xantrex inverter has a 12000W surge capacity and can carry that load for a lot longer than the Magnum.  Lastly, the Xantrex’s “load support” feature seems to be more advanced than the Magnum and that would come in really handy if we need to run some really heavy loads.

Our total lineup of Xantrex products is as follows – and I’m just linking out to these on the Northern Arizona Wind & Sun website as that’s where we bought them from – on a July 4th sale, including freight shipping, it came out cheaper than getting them from Canadian suppliers.

Also, Northern Arizona Wind & Sun has a great set of forums with tons of helpful members, I highly recommend it if you want to do some more reading on some practical topics.

At any rate, with the above setup we should be plenty good to start, and we can always add up to two more inverters and more charge controllers, if necessary.  I think we will probably be ok with the above but we’ll only really find out once we get the house built and start living in it!  Because the inverters are the core of the system, we will probably purchase a second unit to have available as a standby in case the installed one fails.

Thanks for reading and I apologize for the lack of pictures, but I did promise to do some posts on this stuff previously and I wanted to make sure I followed up!  Again – any questions, hit up the comments section below, or post on Heather’s facebook!

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