[RE-wrenches] Off Grid Inverter Replacement Questions

[John Blittersdorf]

Allan,
    I would replace with a VFX3524 and a Mate3 as long as the backup
generator is big enough.  FX's don't load share or gen support. I have had
lousy luck with getting several magnums repaired.  All have been switched
to Outback.  The Radian would be a nightmare to install compared to a
single FX.  I sell Radians primarily for grid tie backup systems and very
high demand off grid. And to replace Magnums.  I have had no trouble with
Outback service and getting boards for on site repairs. Quality of boards
OK. The Mate 3 is more intuitive than the Mate and has lots more
information.  Works fabulously with OpticsRE for monitoring.   I have a
remote mountaintop transmitter site that has been a nightmare for years and
now we finally got all the pieces together at one time to make it work..
Good generator (EcoGen) new batteries, and 4000 watts of solar on top of
pole racks (to self clear of snow) VFX3648 with IOTA 12v battery charger
for the DC Loads, and the MATE3 hooked up to the internet and OpticsRE.
All is now calm on the mountaintop.

John Blittersdorf
Central Vermont Solar & wind

On Fri, Jan 30, 2015 at 8:02 PM, Allan Sindelar <allan at sindelarsolar.com>
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, and these expensive units don't adapt as well as
> replacements in older home systems. 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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