SW4048 showing its age...

RussInSanDiego

I installed my PV system in July, 2001. I always figured the panels would outlast their 25 year warranty, but worried about the inverter, an SW4048.
Well, sure enough, its time has come.
For the last year or so, it would occasionally decide that the grid was out of spec and switch to inverting mode, usually in the middle of the day. After 5 minutes, it would switch back to AC bypass. The only real problem with this was that the switchovers were kind of rough. I have several computers running, and a couple of DVRs, and they don't like the dropout during the switchover. When we first got our system, these switching between bypass and inverter were almost indetectable, but not anymore.
Friday night was the last straw. Around 9 PM, the SW started cycling. 5 minutes inverting, 1 minute on bypass, and then back again. And each time, kicking all our electronics in the, uh, electrons.
Around 2 AM, I pulled the service disconnect and performed bypass surgery on the AC, and shut my SW down...
Any opinions on what my next move ought to be?
Repair doesn't seem terribly likely.
Replacement options for a 48 V battery-backed 4KW grid-tie inverter seem to be the Outback GVFX3648 or Xantrex XW4548.
Any suggestions?

mike95490

Re: SW4048 showing its age...

try to get a RMA for repair, and you may get a core deposit credit for XW series ?

RussInSanDiego

Re: SW4048 showing its age...

Perhaps, but on the Xantrex website, my search for XW4548 turns up exactly NOTHING!

keyturbocars

Re: SW4048 showing its age...

You can find the information on the XW inverters on the Schneider Electric site:

http://www2.schneider-electric.com/sites/corporate/en/products-services/renewable-energies/products-offer/range-presentation.page?c_filepath=/templatedata/Offer_Presentation/3_Range_Datasheet/data/en/shared/renewable_energies/xantrex_xw.xml&p_function_id=5099&p_family_id=5279&p_range_id=7654&f=F13%3ARenewable%20Energies~!NNM1:Solar+Backup+and+Off-Grid+Systems~!NNM2:Backup+and+Off-Grid+Systems~!NNM3:Xantrex+XW

What a huge link! If it doesn't work, then you can just go to the Schneider Electric site and search from there.

Also, the prices I've seen in the past have had the XW4548 and XW6048 at almost the same price. You might consider the XW6048 with extra room to grow in the future.

Edward

Ralph Day

Re: SW4048 showing its age...

Russ
Do you interface the grid with the GTI module from Xantrex or direct with the SW? I'm off grid with mine so didn't use the GTI that came with the system. Solar Guppy or RCAinFLA are the Xantrex gurus here. Take their advice to the bank.

Ralph

RCinFLA

Re: SW4048 showing its age...

Make sure the grid is not the problem. At least check line voltage as if it is low would cause a similar problem. Make sure your neutral return is solid by checking L1-N and L2-N voltage with various 120vac loading.

If you have GTI adaptor remove it from ACin path. They have a reputation of the inline choke going bad.

Are there any alarms that show up, like overcurrent?

Power relay contacts might be getting bad. Switchover gets a little erratic when contacts are severely pitted causing some contact sticking when relay releases. The relay contacts take a beating if you run the inverter all the time (like I do) for immediate UPS switchover as just about every time the grid goes down there is a momentary overload on the inverter and the relay contacts open under high current.

If it is a dual series stack arrangement try removing stacking cable and run each unit individually. (shut off 240 ac load breakers)

RussInSanDiego

Re: SW4048 showing its age...

Ralph Day wrote: »

Russ
Do you interface the grid with the GTI module from Xantrex or direct with the SW? I'm off grid with mine so didn't use the GTI that came with the system. Solar Guppy or RCAinFLA are the Xantrex gurus here. Take their advice to the bank.

Ralph

I go direct. My installation predates the requirement for the GTI.

RussInSanDiego

Re: SW4048 showing its age...

I don't think my problem is with the grid. It's possible, but unlikely. Even the SW's own meters showed the grid voltage as being at 120V. I suppose if I had an oscilloscope (do they still make those?) I might be able to see amplitude or phase jitter, but I kind of doubt that's my problem.

As I mentioned in the preceding post, we don't have a GTI.

Other than these mostly false detections of bad AC1 In, the inverter section rarely gets any exercise. Until the recent flakiness, it would typically trip on only once or twice a year.

I had wanted the battery-backed system because I'm a software developer who works out of my home -- I didn't want to have to contend with any momentary outages. And, at the time, I was anticipating problems with the grid due to the bizarre "deregulation" games that had been legislated in California. You know, the BS that lead to the whole Enron fiasco? Artificial power shortages, were becoming common due to market manipulation.

No, no error alarms ever show up. Many months back there was a completely erroneous "generator start" error that showed up (probably unrelated to this misbehavior) -- which is funny because nothing has ever been connected to AC2, and I'm pretty sure I didn't have any generator startup configured.

I only have a single-phase system -- no stacking.

RCinFLA

Re: SW4048 showing its age...

You can change your grid connection from AC1in to AC2in and see if things clear up. It is perfectly okay to run grid on AC2in.

Your gen alarm is common mistake from accidently pushing the green Gen menu button and moving cursor or engaging battery equalizing from this menu.

RussInSanDiego

Re: SW4048 showing its age...

Just for a follow-up, I did end up checking the line in voltage -- and there were no problems on the grid.

As for hooking up to AC2 -- good thought, and that might be slightly better than bypassing the inverter, but not by much:

1. Chances are, it will have similar issues characterizing AC2 as it's having with AC1. And even if not...
2. You can't push power to AC2, so I can't sell any excess

Bottom line:
I could probably get an RMA from Schneider Electric, paying perhaps $800 plus shipping to repair the AC input measurement electronics plus what's probably a crapped-out relay that's causing rough switchover between inverter and line power. That would give me a repaired-but-still-10-year-old SW4048 for around $900 spent.

Instead, I ended up buying an Outback GVFX3648. $2000 (plus $400 for a Mate and Hub) and I'll have a new unit with a 10 year warranty (California only, $600 extra, apparently). (The Xantrex only had a 5 year warranty that expired in 2006.)

The Outback has the added feature of a serial port that transmits data frames from each of the devices on the Hub (I also have a pair of MX60 charge controllers), so I could set up a computer to collect and forward that data.

As for the SW4048 -- it would be a crying shame to put it in the e-waste pile. As is, it should be perfectly usable off-grid. Or I could spend the repair money and try selling it to someone. What to do...?

Ralph Day

Re: SW4048 showing its age...

Hi Russ
If you can afford a few Costco batteries and the power to keep them charged what about keeping the Sw unit as an emergency off grid backup, ready to go? Is the local utility reliable, do you see it remaining reliable in the future? You've got the makings of a good sized UPS already.

Ralph