[RE-wrenches] Off Grid Inverter Replacement Questions

Tue Feb 3 13:57:55 PST 2015

Wrenches,

Allan’s key technical question is “when should I hesitate to replace a 120V
legacy inverter with a 120/240V unit?”  I’ve reviewed the various scenarios
and options with our engineers and tech support team, and the one “watch
out” issue that could potentially cause problems when replacing 120V legacy
inverters with 120/240V replacements, is how the existing inverter bypass
is configured.   This is something that will need to be addressed whether
the old system was 120V only or 120/240V with multiple 120V inverters.

With a 120/240V inverter, the bypass must operate both L1 and L2 poles
simultaneously.   A common practice in the early days of solar was to use a
double pole and single pole breaker combo with a special wiring arrangement
and a mechanical interlock to bypass both input and output for each
individual phase.  As you note these were typically installed in a SqD
QO403 3-pole load center, but I’ve also done a similar arrangement in other
enclosures which could fit QOU breakers.  This worked well enough back when
the Trace 120V inverter was the defacto industry standard, as the two
stacked inverters were really operating as two independent units, 180
degrees out of phase.  However, this type of bypass cannot and should not
be used with a 120/240V inverter.  If you find this type of bypass in the
old system, plan on replacing it with a modern equivalent as part of the
upgrade.

Other issues relating to upgrading the system would be constrained by site
conditions and customer choice – ie, does the current generator have
split-phase output capability, is there an L2 conductor already in the
ground (or room in the conduit) for both the input from the generator and
output to the house, does the customer want to run higher power loads in
the future, perhaps run any water pumps at 240 instead of 120 and reduce
the starting surges and potential flicker.  I can’t think of a situation
where a home wired for 120 can’t be fed with 120/240, although the reverse
is not always the case.

To answer the question regarding what is made where, the vast majority of
our products and inverter lines are manufactured in Bellingham, Washington
or in Suwanee Georgia (now Georgia might be a little foreign to some, but
last I looked it’s still part of the US-of-A).  Every Radian inverter, G
series inverter and Extreme charge controller is made here in Washington
State.  We do have an international manufacturing policy where it makes
strategic sense – solar is booming in the developing world, and some
regions have local content provisions or taxation barriers that require
in-country manufacturing so there are a couple inverter lines such as our
VFX3024E for the Rest of World market which are made in India along with
the FM60 and FM80 charge controllers.  However, isn’t that what we want, US
businesses succeeding in the global market and bringing that business
home?  We don’t have any manufacturing in China, nor is there any plan to
do so – however, I’m going to take a moment on a soapbox here related to
China and solar.  China’s citizens look to the West and want access to a
similar quality of life, and the more they burn dead dinos to get it the
more we are all screwed.  IMHO one of the best things that can happen for
survivability on this planet is for China to strongly embrace renewables.
Global solar market reports show massive deployment of PV throughout China
and Asia at all levels, and I’m OK with that.  Bring it on.

Ray, I’d like to work with you on internet discounters, it’s not our
intention to allow folks to undermine the market and devalue what reputable
installers such as yourself bring to the table.  However, I have to push
back on bashing our technical support team.   David, Katee, Jorge and the
rest of the team  work hard to provide trained and knowledgeable support
for all of our customers, not just the ones that belong to some kind of
loyalty club.  The people answering the phones here have experience on the
manufacturing line, service depot or education in Electrical Engineering,
we’re proud to have a couple Veterans on the crew, and everyone goes
through both our CTP and SEI training classes.  If a couple of hiring
notices in the past have caused you grief I apologize for that, but I
challenge you to give our team another chance.

Peace,

Phil

Philip Undercuffler

Director, Strategic Platforms
OutBack Power Technologies

17825 59th Ave NE, Suite B, Arlington, WA 98223

360.618.4306 office  |  425.319.2821 mobile

www.outbackpower.com

On Sun, Feb 1, 2015 at 6:19 AM, Tump <tump at swnl.net> wrote:

> Allan, are you planning on replacing the battery bank as well? If so SMA
> is always first choice, despite their price point.  As with ANY inverter
> you will probably have an issue. As remote as site is, I always consider
> what manufacture really does compensate you and how quickly do they get you
> a replacement...... Hands down SMA. 120 SPh works with the old gen set,
> works well with the Trace DC250, (and these expensive units don't adapt
> as well as replacements in older home systems) NOT!, talks to Midnights
> CCs any 220 load is readily installed w/ a t former. No longer are the
> manus making boards readily available so no more field servicing.
> If the battery bank is not to be replaced then the OBVFX product line,
> these units do not need additional software/computer/internet service to
> service unlike the some others.. .. "oh yeah you need to remove the 01-27 &
> replace it with the right file 01-277" sound familiar to any one else?
> TIME VERSES LABOR your last sentence would be a wake up call all the
> $$$$$$$ you will need to upgrade this old system why would you use anything
> other then the SMA SI if you too are going to replace the batteries.
> I also will do a bench test so I am not surprised with ANY remote install.
> Pain in the butt but certainly lot less problematic for you and your
> reputation.
> On Jan 30, 2015, at 8:02 PM, Allan Sindelar wrote:
>
>  Esteemed Wrenches,
> This question is prompted by a specific customer's situation, and I have a
> question related to this, but I'm mainly using the situation to ask a
> broader question.
>
> The specific situation: A customer's Xantrex SW+2524 has been acting
> erratically. Fixing the inverter is not the issue; the client is quite
> remote, and costs of diagnosis, parts and labor for these legacy units have
> gone up enough that the customer has already decided to replace the unit
> with a current product. From my perspective, the issues at hand revolve
> around how to safely and cleanly install a modern inverter into a system
> structured around old equipment.
>
> The specific question: Outback's FX series is the current product that
> most readily replaces the SW/SW+ series: it's also 120V in/out, and it has
> DC on the right and AC in/out on the left of a horizontally-laid out unit.
> However, several times in recent years I have heard disparaging comments,
> both here and in private conversations, about the purported drop in quality
> of Outback's inverters and controllers since Alpha bought them, but
> specifically because units, or parts of units, are now made in China,
> rather than in the U.S. What I want to know, please, are answers to two+
> questions: 1) what's the real scoop? what is now made where? and 2) what
> actual experiences, specifically product failures, have any of you had that
> directly relate to changes directly attributable to overseas production? In
> other words, how much of this is real and how much is rumor?
>
> The bigger question (and this issue will come up frequently in the coming
> years): the SW+, like the SW before it, operates at 120V AC on both input
> and output. More and more modern battery-based inverters input and output
> split-phase 120/240V AC. When should I hesitate to replace a 120V legacy
> inverter with a 120/240V unit?
>
> Among larger whole-house single inverters, Outback's FX and VFX units
> operate at 120V, but these are older models. SMA's Sunny Island is 120V
> only, but this is generally considered a weakness in typical SI
> installations, . Magnum's MS4024 is available in either configuration.
> Outback's Radian and Schneider's XW and Conext SW are only available as
> 120-240 units.
>
> Here are the issues that I see:
> Don't do it if a backup generator is 120V AC-only. It will work, but is
> hard on the inverters, as all charging current will come in on one leg of
> the inverter's AC input. Fortunately, relatively few generators are
> 120V-only; pretty much just the smaller inverter-generators. Most cheaper
> gennies are 240V, and either run through a step-down balancing transformer
> (which would be taken out with the old 120V inverter) or run out of
> balance. Many better portable generators have a 120/120-240 switch, making
> it necessary to only replace a cable and plug to add a second hot conductor.
>
> Also, most older AC switchgear, such as QO403 inverter bypass switches,
> are set up for single pole breakers, and would thus require replacement,
> and reworking in general on the AC side to handle two hot input and output
> conductors.
>
> But once the jumper between the two hot legs is removed in the AC main
> panel, and two hots are connected, making the panel 120-240, what are the
> concerns that I might not have anticipated? Are there any hidden dangers,
> or situations where this change could cause problems, especially in AC
> distribution?
>
> Thanks in advance. I hope that I don't regret posting this late on a
> Friday...
> Allan
> --
>
> *Allan Sindelar*
> allan at sindelarsolar.com
> NABCEP Certified PV Installation Professional
> NABCEP Certified Technical Sales Professional
> New Mexico EE98J Journeyman Electrician
> Founder (Retired), Positive Energy, Inc.
> *505 780-2738 <505%20780-2738> cell*
>
>
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