I just started this tread so if you have opinions or want to just express yourself there would be a place to do it !!

Just keep it clean

Thanks

Is there hope for the Xantrex ST & STXR series? I purchased a ST2500 about a year ago, knowing that there were problems with the firmware. Since firmware can be upgraded, I ***umed that there would be future releases that would correct the problems. After all, how difficult a technical problem is it to design a MPPT algorithm for an inverter? As we know now, it is impossible for the current engineers at Xantrex. Their solution to the ST problem with the status display showing bizarre behavior (MPPT thrashing) has been to dumb down the display on the STXR and not show the disturbing numbers.

How long should I hang on to the hope that Xantrex will fix the ST/STXR? Have they already written me off by declaring my ST an obsolete version that is no longer getting development? Even though the STXR behaves even worse?

I like the specifications of the ST/STXR. Using 6 strings of 4 panels each is a good design. The 48 volt nominal design seems inherently safer than the SunnyBoy's requirement to string everything together for an operating voltage of up to 600 volts. And I suspect that the SunnyBoy is much more sensitive to unnecessary shutdowns due to grid impedance anomalies. The ST/STXR has a built in fan, while SMA is considering how to add a fan. While I prefer silence, if a fan is necessary, then it should be included. The basic designs seem to favor the ST/STXR functioning more of the time, at safer voltages, and at lower temperatures. The reality is quite the reverse - the SunnyBoy reliably delivers about 25% more power than the ST/STXR.
[img]images/smiles/icon_mad.gif[/img]

I have a pair of ST-2500s running from identical 16 module KC-120 pannels and the units also exibit the same startup problems. The West unit start a good hour after the East one, and produces about 10% less each day. While in its early morning thinking mode, it cycles the fan on for 30 seconds then off for 20 seconds and does this for an hour. Finnaly it starts and produces at approximately the same level as its East twin. Complaints to Xantrex get a technican who listens politely, but offers no solutions. The West unit also exibited another unusual characteristic this summer in that it would produce a high pitch squeal for 20 seconds out of every minute, going for hours at a time. The unit is in the shade on 100+ F days. Same technical advised that when it quit producing, I should let them know and if it was still under warranty, they would fix it. It's still running,so I guess the neighbors will just have to suffer. Squeal goes away when the days get cooler. [img]images/smiles/icon_confused.gif[/img] null[email]null[/email]

I have started to respond to this post a few times since I first saw it yesterday. I didn't like the way my response was rolling up (primarily because I felt like a flameboy with both barrels blasting and I don't want to come off that way). [img]images/smiles/icon_rolleyes.gif[/img]

A little background:

I came close to getting a Xantrex inverter before I started hearing about problems with their product. Then I saw the SMA/Xantrex comparison article in Home Power, which confirmed what I had heard.

Frankly, I would be furious if my experience with these inverters was the same as you describe.

I realized that maybe we all need to know what Xantrex is really willing to do about your problem (if anything) and how clear it is to them that you really have a problem. I also realize that some "hard core" evidence for Xantrex that you have a sick inverter might be in order.

Problems &/or issues (by order listed in your post):

1> West inverter cycles the cooling fan on & off before it even starts producing.
2> West inverter starts producing an hour after east (this is an issue only if both systems really are "twins" as you state).
3> High pitched squeal from West inverter.
4> Neighbors ("just have to suffer") impacted by your installation.
5> Having to wait for west inverter to fail completely and "if it was still under warranty, they would fix it".

Thoughts about these issues:

Item 1: Does Xantrex have an explanation for the West fan cycling on and off before it starts producing? Why doesn't East do the same?

Item 2: Does Xantrex have an explanation for the difference in starting times (again, only if these systems are truly "twins")?

Item 3: Does Xantrex have any explanation for the high pitched squeal? And again, why only West and not East?

Item 4: Neither you nor your neighbors should have to endure a high pitched squeal from your inverters (note that some noise is understandable while in close proximity to the units, although you would expect the noise would be closer to 60hz hum than a high pitched squeal). The relatively young Solar Industry does not need this kind of "ill will" over how the technology impacts people, and I sincerely hope your neighbor isn't the type to write letters to the editor of your local newspaper... As an aside, I'd bet $5.00 that any AM radio in proximity to this inverter while it is squealing is also useless.

Item 5: This is probably my biggest "hot button". You have described what I consider a defective unit that will fail completely at some point, and it is still under warranty. If it totally shuts down after the warranty expires, you get to foot the bill for the defect!

Thoughts on Next Steps:

Have you tried swapping the East inverter for the West Inverter? With all other conditions remaing the same, if the problems move East with the interver, I'd say you have a very clear cut case.

Did you install the system yourself or was a contractor involved? If a contractor, have you pointed this problem out to him/her? I would press the contractor to get a unit swapped out ASAP. If you still get no satisfaction, then you should consider talking to the contractor state license board (I see you are in CA - www.cslb.ca.gov) about the problem. It would probably be a good idea to tell them up front you think this is problem with a product sold by your contractor and not the quality of his/her work.

If you "rolled your own", have you talked to the organization you bought the unit from? I suspect you can get some help with one or more organizations that talk to consumers of products, such as CA Dept of consumer affairs (www.dca.ca.gov), AHAM - the A_sociation of Home Appliance Manufacturers (www.aham.org) &/or The Bureau of Electronic and Appliance Repair (www.bear.ca.gov)

Also, since these units are grid tied and they are UL approved, you could consider contacting the California Public Utilities Commission (www.cpuc.ca.gov) &/or Underwriters Laboratories (www.ul.com) about these issues.

Death to Xantrex?

OK, by now you might think I hate Xantrex - this is simply not true. Actually, I think that if I were Senior Management @ Xantrex, I would be pressing my engineering department bigtime to get problems like this nailed and satisfy my customers ASAP.

Note: I don't know if this is a problem that the engineers should "own" alone either, frequently Management is the larger part of a problem with product issues, especially where delivery timeframe incentive bonuses &/or marketing pressures cause product to release before it is ready.

I think that competition is king. SMA appears to have this Xantrex line running for their life (whether they know it or not). I think it would be great for Xantrex to save their [backside] by releasing an inverter that "raises the bar" in all ways relative to SMA (note applicable areas such as overall efficiency, customer satisfaction, reliability, etc).

Xantrex better hurry though, their reputation already looks tarnished... remember that one "Oh sh_t" can wipe out a hundred "Attaboys".)

(Administrivia: Be Safe / Only my opinion / Other viewpoints=invited+encouraged)

(c) 2002 Roger@vipmail.com

Followup info: To be fair, I noted that there is an update notice (released Oct 1, 2002) on the Xantrex website that refers to "under certain conditions, some customers have seen performance that falls below what we would consider industry-leading".

The article claims that the upgrade is expected by the end of December. I don't see that all the issues discussed would fall into this upgrade, but the problem(s) they are fixing are not clearly described so perhaps Xantrex can speak to this?

-Roger

Hi Rob, Alan and Roger,

Thanks for noticing the post on www.xantrex.com for the upgrade program. There are significant financial investments being made to "step up to the plate" and meet the performance of other competitive products. The issues being addressed are: MPPT energy harvest efficiency including cloud tracking, fan operation, noise, display issues, units arriving DOA, wakeup routines, sheet metal inconsistencies, and more. This work is currently in very capable hands and Xantrex is pouring the in the resources to support these efforts. Please know that Xantrex is standing 100% behind its equipment and you, the customers.

Thank you. Tobin Booth, Xantrex Technology

Tobin, Thanks for the reply. I will certainly be looking forward to the revised firmware. The West unit is 10 ft lower than the East unit and gets shaded by East at sunrise. There is a middle tracking array with 8 pannels and it gets no shade from East. Four of the mid panels are attached to the West inverter and as the sun rises, sets of four pannels on West are taken out of the shade sequentially. The fan routine normally starts after all West pannels are exposed to full sun. Until then the LCD just shows 247VAC and 83VDC, 0000 Watts. I also have noticed problems with the moving clouds as noted by the recall notice. Of course, from where I live in the desert, clouds are a rare sight. This summer that was different, with lots of clouds. I also had the same problems noted, elsewhere in this forum, with the mechanical layout...but the nice aluminum case and a hole punch solved that one quickly. I'll be glad to work with your company on this issue and it should be noted that even with these blimishes, the inverters are producing an average of about 600kWh each month.

It is good to hear that top Xantrex management has finally decided that their performance to date has been unacceptable. Customers have only been saying this for several years. Without SMA demonstrating the poor performance of the ST2500, they would still be dismissing our complaints as uninformed dreamers.

The announcement specifies poor cloudy weather performance as the problem they are working on. Even more basic is poor performance during stable conditions. I can be watching a bright cloudless sky, as the ST2500 thrashes up and down between producing 800 watts and 1600 watts. Earlier firmware caused it to thrash between zero and 1600, so they have improved from the first attempts. The next problem is that the maximum performance seems to be throttled back. I can be making 800 watts at 2 amps per string (times 6), and when the amps go up to 5 as the sun goes higher, the watts go to 1400. I understand that watts equals amps times voltage, and my complaint is that the MPPT algorithm is doing a poor job of controlling the voltage.

The best MPPT implementation currently appears to be the OK4 (locally known as the Trace Microsine) inverter. An interesting performance test would be a side by side comparison of power output per panel with an OK4 inverter versus the SMA & Xantrex units. The OK5 looks even more interesting, since it can support a 48 volt string like the ST2500 uses. You could even take one string off the ST2500 and move it to an OK5. The biggest problem with the OK4/Microsine is the price per watt, and the OK5 appears to be a major improvement in that department. Lots of small MPPT inverters instead of one large inverter is attractive where the panels are subject to different orientation and/or shading. It will be a while before the OK5 is available in the US, but it will be a welcome addition to our current choices.

Where can one look at the spec's on these inverters ??

The microsine hasn't been made in years I thought ... and was it ever UL1741 approved ?

The OK4/OK5 are made by a Dutch firm named NKF Electronics. Check out www.nkf.nl/electronics/photovoltaics

The MicroSine is just an OK4 marketed by Trace. Trace dropped them, but the OK4 continues to be available. The OK5 will be priced at about $1.10/watt, with a target of $0.50/watt when production is fully ramped up. I'd buy 2400 watts of inverter for $1200! They've got their work cut out for them in establishing their European market, so I wouldn't expect them to market directly here for some time. On the other hand, the OK5 comes in 120 & 240 volt versions, both of which autoswitch between 50 & 60 cycle power.

The MicroSine does have UL 1741 approval. Care to bet how many installations have power company approval? My guess is zero, considering the ease of just skipping that step. The OK5 is probably designed to meet UL 1741, but until someone in the US jumps through the hoops we're probably talking guerrilla installations here.

There is another company named MasterVolt that makes a device similar to the MicroSine. As far as I can tell though, it is only available in a 240 volt / 50 cycle version. It is basically a wall wart (plug in transformer) that inverts power from 1 or 2 solar panels.

[ October 05, 2002: Message edited by: Rob Larson ]