[RE-wrenches] Off Grid Inverter Replacement Questions

[Ray Walters]

Hi Allan;

You didn't mention the DC load center used, but that would effect the 
decision, as well as the relative wall space.  I've found customers were 
very happy with an E Panel setup, as they gained floor/ wall space with 
the upgrade as well. I'm tired of still working in old Trace DC 250 
boxes, if I don't have to.
For inverters, my vote would be for the Magnum over the Outback, not 
that we've had reliability issues with either, but mainly the bang for 
buck factor.
The Magnum has the 120/ 240 vac output, more surge and continuous rating 
than an Outback, and the remote is much lower cost and much easier to 
use than the MATE 3.  I also appreciate that Magnum is policing internet 
discounting, while Outback is allowing an "anything goes" pricing 
policy, that makes it hard for a reputable installer to compete.  Magnum 
gets my customers more power for less money, and I can still afford to 
offer a service warranty and pay the bills.  I think I really starting 
moving away from Outback when they advertised for technical support 
personnel: "no experience necessary".

R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760

On 1/30/2015 6:02 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, 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 <mailto: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 cell*
>
> **
>
>
>
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