[RE-wrenches] Enphase Micro Inverter Energy System

[Dana Brandt]

Max,

We recently finished a small installation (2.4kW) using the Enphase
micro-inverters and have been fairly pleased with them.

The most notable thing about Enphase was their excellent tech support. I
always got prompt attention from knowledgeable people in this country. This
is in stark contrast to tech support experiences with other inverter
manufacturers. Enphase's is quite possibly the best tech support I've ever
gotten for anything.

For design reasons we were forced to use Unirac SunFrame rail which required
some extra effort and tight tolerances in mounting the inverters to it. If
at all possible use a SolarMount-type rail. This is what the inverters were
designed for.

Our recent installation feeds a 120/208 3-phase system. It's important to
note that Enphase's 240V and 208V inverters are different models and are not
field configurable. Also, the 3-phase inverters are wired to spread across
all three phases. This is elegant from an engineering perspective because it
balances the inverters across the phases. However, on a small system I think
it's more hassle than it's worth. It required a 3-phase breaker and a 7-jaw
production meter base, which were minor added expenses. Since the largest AC
branch circuit you can put together with the 208V micro-inverters is 4.2kW
DC, it seems to me that it would be best to leave them all across two legs.
Then installers could spread out multiple branch circuits across the 3
phases as we do with single inverters and keep things simple on small
systems. All in all, it's really not that big a deal either way, just be
aware up front what the requirements are.

The energy management unit (EMU) monitoring is a near requirement. It's the
only way to view the output of the system aside from the production meter. I
wouldn't install an Enphase system without one. If one of the inverters
fails the EMU data will be the only way to track down which one. It
communicates with the inverters over the 60Hz line and uploads the data to
Enphase's Enlighten website via the internet. You can log in and see in
almost real time the output of each individual module as well as any number
of energy production reports and the like. It's addicting!

I think in certain applications (very small systems, partial shading,
multiple module orientations) they're a great solution.

Best,

Dana

-- 
Dana Brandt
Ecotech Energy Systems, LLC
www.ecotechenergy.com
dana at ecotechenergy.com
360.510.0433



On Fri, Feb 6, 2009 at 5:37 PM, Max Balchowsky <max at seesolar.com> wrote:

> I've been asked to evaluate a set of plans that came accross the counter of
> a local municipality recently. It was the microinverter system by Enphase.
> I've seen this product, but this is the first actual installation I'm
> exposed to. Has anyone installed these?
>
> Max Balchowsky
> SEE Systems
>
>
>
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