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I am installing 36 Canadian CS6P panels in an off grid setup. I would like to use enphase microinverters

I am trying to set up an off grid system.  I have 36 solar panels and would like to use the enphase inverters.  However, I have been told they need to "sense" the 60 cycle connection of the grid.  Are there any inverters that will do what these do and do not need the grid???

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Martha on June 29, 2012 - 7:37am
I'm assuming that when you say "do what these do", you mean MPPT power conversion at a module level and also module level monitoring.  The Enphase is a UL 1741 listed inverter - that means, if there is no stable grid voltage and / or frequency, it must shut off completely until normal grid signals are reestablished.

It appears, however, that with some artful product combining, the Enphase (and other normally grid tied equipment) can be used in off grid situations. Here's a recent CivicSolar article to that effect: http://www.civicsolar.com/resource/microinverter-application-grid-pv-systems

So, assuming this is going in the right direction for you, why would you use a grid tied inverter in an isolated situation? You can't sell power to the utility, and inefficiencies of conversion, though small, can add up.

Here are some options:
  1. Use a power maximizer with a "high voltage" charge controller. The power maximizer gives the module level VDC MPPT and monitoring and the charge controller allows for longer strings - up to 600 VDC. Here are examples: TIGO and Xantrex XW-MPPT
  2. Use a regular old MPPT charge controller, and don't worry abut string level monitoring. You will be limited to 2 modules per string and while you won't get the shading resolution of the module level MPPT, you will be able to isolate and check the strings at the 18 fuse positions in the combiner box.
Hope this helps - please respond with more details of your situation if you need more clarification