SW 5548 dropping the grid

ronrosenfeld · June 2016

I have a pair of SW5548's in series stacked mode, providing 120/240. We were off-grid for almost 15 years, and brought in grid-power about 18 months ago. After some initial problems, traced to a missing jumper, both inverters would work in Sell mode -- powering the house from the grid, and switching seamlessly to inverting when they would drop the grid. By seamlessly I mean that computers remain powered up; the microwave clock continues to keep time; and we do not note the lights flickering.

The problem is that they are dropping the grid when the grid power is within specifications. They are doing this multiple times a day, and they are NOT dropping the grid at the same time.

I have measured the power quality at the AC1 input to the inverters using a Fluke 1735 power logger; and the power company also attached a logger recently to the meter during a time when the inverters dropped the grid multiple times, and no abnormalities were noted.

The units were purchased in 2000, initially with Revision 4.01 firmware; and were later updated to Rev 4.10 which made them compatible with UL1741 First Edition requirements. (And these were approved by my power company to operate in sell mode).

One person thought there might be AC Ripple on the DC input from the VCS-10 controller. Measurements with a Fluke Volt-Ohm meter (yes, I know, this will miss stuff but I don't have access to an oscilloscope) revealed no more than about 1.2VAC; no correlation with increased wind turbine output and grid drops; and also, the grid would still drop even with the wind turbine disconnected from the system.

If it was just a single inverter, I would be inclined to blame either that inverter or something connected to it. If both were dropping at the same time, I would be inclined to blame power quality, or possible a grounding issue. So, other than replacement with a different model inverter (big bucks) that has diagnostics, I'm not sure what to do.

Any thoughts on how to further troubleshoot would be much appreciated.

BOS:

Bergey XL-R 8kW wind turbine
Bergey VCS-10 controller
1.98 kW PV panels
Outback MX-60 MPPT controller
Surette 48V 1640AH battery bank
Kohler 12kW propane generator

Dave Angelini · June 2016

It is big bucks time and was that time years ago!
You have a really outdated system that should not be used anymore as a hybrid.
Having all of this mismatched equipment in grid-tie is a mistake.
An XW or a Radian is the way to go if you must have batteries and the grid. Good Luck

I have seen many MX-60's go to a weird sweep that causes zero output 10 seconds or so, a no no for any system.

ronrosenfeld · June 2016

Obviously, replacement is an option if one has the bucks. That is not what I am asking about. These "ancient" units were designed for and identical models worked in a grid-interactive mode in the past. I am a fan of trying to troubleshoot and fix rather than discard and replace, when feasible. I was hoping there might be someone here with expertise that could advise on troubleshooting and repair. Do you know of anyone with those skills?

littleharbor2 · June 2016

Here's a repair place that specializes in Trace/Xantrex equipment. Hope its okay to post here. It not you can find him on eBay under Trace Xantrex inverters.
http://www.ebay.com/itm/Get-your-Xantrex-Trace-SW-and-PS-Inverter-Control-Panel-Repaired-/231874787018?hash=item35fcd076ca:g:p3EAAOSwwE5WaJ~k

BB. · June 2016

Here is a post with other repair shops listed (you may be able to buy parts from somebody here too):

http://forum.solar-electric.com/discussion/comment/241766/#Comment_241766

-Bill

Dave Angelini · June 2016

Add in that the last years when Xantrex ran their forum, the consensus was to replace with an XW ASAP. This was about 10 years ago.
This was mainly because it is extremely hard to troubleshoot a system that does not have on board diagnostics. The weight of shipping and the huge problem of missing an intermittent made throwing good money after bad, and replacement the smart move. This is about the grid-tie SW. For offgrid it is easy to recommend trying to repair.

ronrosenfeld · June 2016

Thanks to all for the responses and referrals. And Dave, I agree with you about the cost of shipping -- I wouldn't bother if I have to ship. But if I could troubleshoot here, it would be a lot less expensive than a pair of XW5548's, generator control box, and whatever else I might need to bring it up to today's code specs. A major problem with troubleshooting is getting a copy of the schematic. Heck, Trace never even published details on the Tech menu for that inverter (or even that it was present)

t00ls · June 2016

Ron...you would only need 1 xw 5548, as it has the ability to do 120/240 in one box....2 of them would effectively give you 10,000 watts instead of 5500 watts

ronrosenfeld · June 2016

t00ls... I did think about that. But there have been times in the past when we've gone over the 5kW (and don't forget that the maximum output goes down with increasing temperatures). And also, the XW 5548 has only a 110A battery charger vs 150 A for a pair of SW 5548's. When we replace our battery bank (1640Ah at 48V) we could probably make do with the smaller charger, but I doubt I could reconfigure the house and my S.O. to have reliable power with the limitation of a single xw 5548 (or even the 6848).

Dave Angelini · June 2016

An XW 6848+ will easily out perform stacked SW's. Easily! Done this many times.

ronrosenfeld · June 2016

Dave,

What do you mean by outperform? My main consideration, if I replace my inverters, will be the continuous power output rating.

Dave Angelini · June 2016

Outperforms in specification, design, and the most important consideration. It is supportable for at least 10 years from now.
It has power factor corrected charging, convection cooling, and all the graphing/logging/warning/fault support from COMBOX out to the WEB/internet. It was a no brainer 10 years ago when xantrex said they were not going to support the grid SW's.

ronrosenfeld · June 2016

I have no doubt that a XW6848 is a better unit than a SW5548 in many respects, but I don't see that the maximum continuous power output specification is higher than a pair of SW5548's, unless you assume that my whole house average PF is less than about 0.6

Dave Angelini · June 2016

The XW is DSP and specs can be changed easily depending on what the requirement is. That was the original DOD requirement. Tested and passed up in Livermore CA. at the National labs.
It is your house and your life! If you want me to interpret specs for you please send me a check! Good Luck!

ronrosenfeld · June 2016

Thanks for the information and the good luck wish.

Vic · June 2016

Hi Dave,

We have run SW+ 5548s - Stacked here, for some years. They are solid, although, do wish that they did a few things a bit differently.

I sure hope that Schneider has fixed most of the bugs in the XW 6048s, that Grid connected users had complained about for a number of years, in the new XW+ line of inverters.

You did mention above, that the XW+ 6848s were "convection cooled". How could this be possible in an inverter/charger that will need to rid itself of more that six hundred watts of waste heat, based on the Typical Inverting Efficiency curves in the manual? Seems to me, that in any reasonably-sized enclosure, that this would be very difficult, without a very cold ambient temperature.

Not to argue ... some day we will need replacement inverter/chargers, and the XW line may need to be on the list of candidate units.

Thanks for any clarification. Vic

Dave Angelini · June 2016

All Xw's are convection cooled with the aid of fans. It was for desert cooling apps for the US military. I have met the designers and respect them. My steady 1,000 watt cooling load for 15 hours barely cycles the XW fan which has 3 speeds. Air enters under the XW and exits from the top. The point is that if the fan were to fail and I have never seen that in over 50 of my clients systems, there is a very good chance the unit would keep running for a very long time. The new SW is like your old SW with sideways cooling. 5 year warranty against 2 years for the SW. All can be optioned for more years from Schneider.

The "bugs" you refer to are mainly from grid apps with people who have no training and are DYI types. A hybrid is always a challenge and the same "bugs" happen with the Radian. Solar Guppy never had XW grid trouble and helped many here. I do not have the patience for a hybrid unless I am billing to take care of my families good welfare.

Always nice to be living offgrid, ALWAYS!

Vic · June 2016

Dave Angelini said:

All Xw's are convection cooled with the aid of fans. It was for desert cooling apps for the US military. I have met the designers and respect them. My steady 1,000 watt cooling load for 15 hours barely cycles the XW fan which has 3 speeds. Air enters under the XW and exits from the top. The point is that if the fan were to fail and I have never seen that in over 50 of my clients systems, there is a very good chance the unit would keep running for a very long time. The new SW is like your old SW with sideways cooling. 5 year warranty against 2 years for the SW. All can be optioned for more years from Schneider.

The "bugs" you refer to are mainly from grid apps with people who have no training and are DYI types. A hybrid is always a challenge and the same "bugs" happen with the Radian. Solar Guppy never had XW grid trouble and helped many here. I do not have the patience for a hybrid unless I am billing to take care of my families good welfare.

Always nice to be living offgrid, ALWAYS!

Well in the Comment above, you said,

"... Outperforms in specification, design, and the most important consideration. It is supportable for at least 10 years from now.
It has power factor corrected charging, convection cooling ... "

And, you were comparing the Radiation/Convection/Fan-cooled SW 554s as being poorer because the XW+ 6848s were "convection cooled" To me, this is an absolute statement. Convection cooling, not with fans, just convection. It is Binary, convection (NO fans) or not convection -- with fans and/or whatever else for cooling.

This may appear to be a fine detail, but fine detail is what Engineering is all about.

The SW+ 5548s here do not need their fans at all until the loads exceed about 2200 watts for several hours, in a room that is about 70 F degrees or less. This also holds for charging batteries power as well.

There were many users of XW 6048, and 4024s who seem quite disappointed that Schneider would not do anything for their performance concerns regarding the way that these units interacted with the Grid ... they were begging for Updates for some years. Seems that the "solution" from Schneider was to bring out a new series (or two) of new inverter/chargers. This would be an expensive "Update" for the legacy users of the previous XW line.

Did not pay too much attention to the detail of what were the Grid-connected XW issues, but there were a number of disappointed owners of expensive XW inverters that seemed unhappy. Most of these folks seem gone from this site in the past year or so.

Just a detail. FWIW, Vic

ronrosenfeld · August 2016

Well, if anyone is still following, I have finally decided to replace my SW5548's.

After some discussions with a repair technician at a certified facility, I was going to try replacing the AC Board in my #1 inverter, that containing the only moving parts (fans and relays) and the most likely to be causing a problem, according to him. Since I have a spare SW5548, it would be a relatively simple thing to do and, if it worked, it would be easy to repair the old board and also take care of #2.

However, while I was setting up to do this, #2 became non-functional. It stopped inverting and also mostly disqualified the grid, with infrequent connects. Since troubleshooting and repair was now likely beyond what I could do at home, I decided to take Dave's advice and replace them.

I considered a single XW6848 and also a single Outback GS8048A. But I decided on a pair of XW5548's (although I am actually getting a pair of XW6848's due to pricing).

Although a single XW6848 (or GS8048) would probably carry the load, especially with their overload ratings, there were other factors that led to my decision to get a pair, and also to get the Schneider vs the Outback.

- A pair obviously gives me backup should one malfunction.
- With just a single inverter, I would not be able to sell back all of the PV and Wind power that I can generate (9.5 kW nameplate). And, in this area, on a windy sunny day, I have seen that amount or a bit higher (in the winter) being sold back. I don't have good data on exactly how much we might lose, but I've seen the wind blow hard for several days in the winter, when the sun is also shining and, when the inverters were connected, they were each selling > 40A (@120V).
- I note that the relay transfer time for the XW is supposed to be around 8 ms. For the Outback, in sell mode, it is stated at about 25 ms. 8 ms is sufficiently fast that my computers won't blink. 25 ms might be too long as the ATX specification for holdup time is 16 ms. (Although the SW5548's, in sell mode, supposedly have a transfer time of 20 ms, and that was tolerated by our computers).

In any event, those were some of my thoughts. Perhaps this discussion will help someone else in a similar situation.

Dave Angelini · August 2016

Ron, you will have some very nice "modern" battery options in the near future from Schneider that will play nice with the (+) series.

ronrosenfeld · August 2016

Is that their Lithium-ion EcoBlade system? It looks promising, but maybe a bit pricey. Although with FLA prices going up, who knows? I will have to replace my battery bank one of these days, and I will surely be looking at the different technologies.

Dave Angelini · August 2016

Can't really say much until after SPI in Vegas. Good Batteries are never inexpensive but down the line there is no reason they can't be reasonable. Early adapters may pay and to many the cost will be worth it.

ronrosenfeld · August 2016

I will be eagerly waiting. I expect my battery bank will need replacement sometime over the next five years or so. Have you any experience with Aquion's salt-water batteries? Low energy density but seems to be more eco-friendly than some of the others. One of the people who maintain my wind turbine installed a set for a customer a year or so ago, but I've not heard any follow-up on how they are doing.

Dave Angelini · August 2016

Aquion will be in Vegas with their XW+ solution. They are not what I am testing though and not Eco Blade which is really commercial.
I am Offgrid now for 24 years and that really is a small piece of the pie that has been getting recent attention because of all the grid uncertainty. Alot of growth from Austrailia and their power cost issues.
The real problem is the market for storage is really more hyped now than real. The great recession of 2008 really has slowed the growth to where residential is a bit of a risk for some of this, It may take too long to be rewarded.
Still, there will be some nice things next year as the 4th quarter is not a time too stock this stuff for distributors.
Commercial storage is a different story.

SW 5548 dropping the grid

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