Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Mangas

Assuming proper in spec and sized installations are there any published failure rate statistics or useful lives for this equipment? 

I was considering keeping a spare Outback controller on hand, but our solar people suggested they are pretty dependable and new (and better) iterations would take their place in the event of failure.

Jim, you have any opinion about this?

BB.

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

The problem with any installation is how affected would be be by failures... Whether it is disk drives and computer data--or your solar installation--availability of parts/ cost of replacement-spare components vs going without until parts arrive...

It is pretty much going to depend on your needs (and how much you wish to spend).

In your case, it appears that you have between two (solar charge controllers) and four (inverter) actively operating components for your installation... If you can live for a week or so with only one charge controller or three inverters--then spending the extra money now is probably not worth it.

However, if it takes a month or two for you to get things through customs--or you you have systems that must have the power (refrigeration, well pumps, hyper expensive generator fuel)--then it may behoove you to obtain major spares now (perhaps even from buy/sell/trade or EBay) while you have the time to spare and no pressing problems.

In general, electronics like inverters and charge controllers are pretty reliable (at least the good ones are) and, typically, have what is called a bath-tub curve for failures... During the first few months of operation you will have "infant" mortality (higher rates of failure) then for 2-8 years (guessing) the failure rates will be quite low--then towards the end of life the failure rates will start to rise again.

In terms of newer/better components coming out now vs four years later--I would probably not hold my breath. In general, the chargers/inverters you have now are pretty reliable and efficient (you are not going to spend $$$ to go from 94% to 96% efficient and you already have MPPT solar controllers). Also, if you where to choose to install a major upgraded design--those changes may require you to rewire the solar panels or battery bank (say from 60 VDC to 200 VDC solar panels or 12 VDC to 48 VDC inverter/battery banks)--and you may not quite want to do that when you are replacing only one failed component--and leaving the rest of the system alone.

From reading your sig-line--it appears you have quite a large and well designed system using good vendors/products (and there are no major changes that would dramatically improve your systems performance/life that I can foresee in the near future). I would only purchase an extra inverter or charge controller if you cannot live with the interruption of a failed controller/inverter. I would worry less about obsolescence in the future. The electronics are already pretty near rock-bottom in pricing today (highly integrated features, automated assembly--much of the "costs" are in copper and other materials that are probably only going up in price). You may see some price drops in the future (China's low labor costs) but you also may see price increases (demand for solar panels as oil costs rise).

A place where you may wish to spend some money is for lightning protection (if you don't have any now and you are in an area where lightning is likely). Unfortunately, there are quite a few ideas about lightning hardening of solar power systems--but lots of grounding and suppressors are probably a good place to start. (and from earlier discussions here--it sounds like the major system failure from lightning is the Inverter Outputs--food for thought on spares).

Good luck and let us know what you decide.

-Bill

crewzer

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Jim, you have any opinion about this?

Mangas,

I’m afraid I’ve no hard statistics to offer. However, I do have a bunch of anecdotal evidence that I’ll share.

My MX60 is 2-1/2 years old and is working fine. This is perhaps more impressive than it sounds, as mine is something of an unofficial field lab for OutBack. It’s been taken apart, upgraded and/or reconfigured at least ten times, and it always works, save, of course, for any quirks in test software. :-o

As boB might say, I’ve managed to never “let the smoke out”, and I’m very happy with both my unit as well as with OutBack’s customer support.

I’m an active member over on OutBack’s forum, and I’ve noticed but a very few units exhibit any truly defective behavior. My recollection is that there were a few component issues during early production, but I believe these were all resolved. The MX is indeed a fairly robust unit, and I think you'd have to push it pretty hard to cause it to break.

For example, although rated for 60 A output, it can be user configured for up to 70 A output. Another example is OutBack forum member "Sparky"'s reference to a 24 V system powered by a 2400 W array... that's 50% above OutBack's recommended limit.

A compromise approach might be to buy an extra control board and an extra fan. These are both fairly easy to replace, and the instructions are posted on-line. See: http://www.outbackpower.com/pdfs_manuals/MX%20control%20board%20replacement%207-14-06.pdf Benefits of this approach are that you could address most likely failures with minimum investment, minimum system downtime, and you could send the spare control board to OutBack from time to time to have the latest SW rev installed. 8-)

I hope this helps!
Jim / crewzer

Mangas

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Thanks Bill and Jim for the excellent analysis.  I appreciate the informed comments.

Since we are in an extremely remote location, we tried to design the system with redundant capacity in mind, so yes we proabably could run everything for a few weeks until the new equipment was installed.  I figure we could limp along with three inverters and/or one controller even running the central air and heat.

We did install a sophisticated grid grounding mat at the field array for lightning protection (I have an 8,000 foot desert mountain peak behind me and the valley floor is a 1,000 feet below us).  Fortunately the electrician's first career specialty was industrial grounding systems.  But, this still is my biggest concern as the desert storms up here can be ferocious.  I'll ask them about added supression systems.

I see your point about the 94% to 98% diminishing returns.  As long as I have durability and dependability that's the bottom line.

The extra controller fan and board is a good idea. I'll get an extra extractor fan too.  I'll do it.

Let me know if you have further advice.

niel

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

i agree with those parts and boards for your backup. furthermore they should be kept in something to protect not just from physical harm, but static harm as well. i'm sure the electrician knows what i mean and what to do. i'd also like to hear more of what the electrician did in his grounding arrangement. describe this in some detail for me if you would.

crewzer

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Let me know if you have further advice.

Off Grid 4x5500W Xantrex SinePlus Inverters/48V DC System/40x185W Panels/68xTrojan 16s/DeSulfinators/2xOutback 60s'/Hydrocaps/Temp Sensors/Interfaced Air Extractor System/Output Into 2x100Amp AC Service Panels

Mangas,

A couple of comments and observations:

40 x 185 W modules = 7,400 W STC into two MX60’s = 3,700 W STC per mX60. That’s a bit over OutBack’s recommended limit of 3,200 W for a 48 V system, but probably not an issue per se if you’re located in a generally warm climate, as PV power output may tend to be a bit on the low side.

I suspect you’ll hear the internal cooling fans running frequently in the summer. It might be worth buying a small 12 V fan to provide additional external cooling by connecting it to the AUX port on one of the MX60 controller’s. You could use the VENT FAN function to toggle the fan at 56 V. Check the MX manual for more info.

40 PV modules and 2 MX controllers suggests 20 modules per controller, and that suggests a 48 V nominal PV array for a 48 V bank of Trojan flooded-cell batteries. Is the array and controller combo able to push the battery voltage high enough – especially in summer – to perform battery equalization?

Hydrocaps… My understanding is they should be removed and replaced with the stock caps before equalizing the batteries.

68 x Trojan 16’s… I’m at a loss to figure out how you managed to get 48 V from this quantity of 6 V batteries… :?

A 7400 W STC PV array will deliver ~105 A to a 48 V system at ~mid-day…. That’s ~3% of a 3,400 Ah battery bank’s capacity. It might be tough to both recharge the batteries and power big loads, so it might be practical to delay some loads until the chargers have switched from B-MPPT to ABSORB mode.

Here are some links to useful Trojan guides and info:

http://www.trojanbattery.com/Tech-Support/BatteryMaintenance.aspx
http://www.trojanbattery.com/Tech-Support/FAQ.aspx

HTH!
Jim / crewzer

Mangas

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Niel, I'll be seeing the electricians in few weeks and will let you know what they did/are doing.  I know then intend to rework the grounding at the field next month.

Jim, the solar mechanicals were installed in an old stone ranch house.  The walls are 24" thick and according to the thermometer temperatures never get above about 79 degrees or below 69 degrees.  We thought this was ideal for the batteries, inverters and charge controllers.

I know they installed the hydrocaps after the batteries were intitally equalized.  We check the levels often but they, so far, haven't needed water since they were installed 9 months ago. Although it was expensive to install them, we believe the savings in maintenance labor was well worth it.  Amazing to me how much liquid the batteries are retaining and the tops are bone dry.

I can hear the MX60 fans running from time to time.  I think I'll try to monitor how often they're running.  Good idea about the aux fan.  I'll talk to them about it.  Since the stone mechanical room keeps everything temperate the air extraction system we installed probably further helps to keep environmental operating temperatures constant.  I'm wondering if we really needed it.  It was my idea.

Per the MX 60 Controller and the inverter read outs, in summer the battery voltages are easily above 52V? I've often seen them as high as 59V.  When we run the AC in the next months, I'll keep some numbers on them to see Sunup/Sundown levels.  We are on the side of a desert mountain with constant sun and unobstructed SE declination angles.  Incidentally, they measured DC line loss from the array to the solar mechanical room and it was barely measurable.  They intentionally used extremely heavy copper wire for the runs which I'm sure helped.

Yes, the array and MX60s' are pushing the system to equalization, no problem whatsoever.

Jim, not sure what you meant about getting 48V from the batteries?  When we start running the two central AC zones more often, I'll see what the charging levels are coming in at and when/how often we get equalization.  I know before we disconnected the heat pumps the system was handling everything but they didn't like the overall power consumption, probably for the reasons you mention.  The HVAC guys intstalled two variable speed 2.5 ton, two stage AC compressors which are 19 SEAR rated (unbelievabe how efficient it's all becoming).  They claim this level of efficiency is very important.  The AC compressors don't run constantly like the heat pumps.  In tests we could easily maintain the AC consumption voltages during the day.  I am hoping we end up at about 47-49V at sunup.  In the next months with constant use,  I'll let you know what the numbers are.  I wish we could somehow get downloadable monitoring telemetry out of the system.

As I mentioned in an earlier comment, before we installed the motor run capacitors (a $ 20 part) on the air handler unit circuits (not on the motor) the violtage levels were in chaos because the HVAC was trying to run constantly.  After the run capacitors were installed the syetsm ran perfectly and power consumtption was nominal.

I took a few pictures of the system with my digital.  Maybe cut and paste post?

rplarry

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Manga
I'm a little curious myself, how did you get 68-6v batteries to make 48v? It takes 8-6v batteries to make 48v and if you have 8 paralell strings that is 64 batteries, so where do the other 4 batteries go? Maybe to a 12v or 24v load such as DC pumps or maybe 12v vhf radios? :-)
Larry

crewzer

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Mangas,

Thanks for all of the additional info about your system and its environment. I agree that the system – and especially the batteries – should all be pretty happy!

Larry did a nice job of explaining my original “48 V” question, so there’s no need for me to pursue that any further.  I’m still curious about the answer, though…

I have no first-hand experience with Hydrocaps. There’s lots of info around that supports the claims of gas-to-water recombination and the reduced maintenance benefits.

Instead, my concerns lie elsewhere. One is that Hydrocaps can apparently get quite hot during battery equalization, so your maintenance staff should be aware of that potential hazard. A related concern is that the Hydrocaps’ life expectancy may be shortened if they’re left in place during equalization. Considering their unit cost (~$25 to $40, I understand) and your quantity (68 x 3 = 204), it might be worth a rough cost-benefit analysis to figure out the most cost-effective maintenance protocol.

Here are links to related Hydrocap comments: http://store.solar-electric.com/hydrocaps.html and http://www.surrette.com/ (see “Caution” note near the bottom of the page).

In summary, though, I like your system’s capabilities, including running a couple of high-efficiency AC units running from a solar energy system… Cool!  8-)

Regards,
Jim / crewzer

P.S. You can post pics (subject to file size limits) via the "Additional Options" link at the bottom of the "Reply" window.

Mangas

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

I apologize everyone. The electricians reminded me there are 64 Trojan's not 68.  I never counted them.  They got a chuckle out of that.  I checked the invoice indeed 64. 

They also said the caps are water misers not hydrocaps.  Thanks for sending me to the website.  I educated myself on the differences.  The water misers still are doing a great job. They said he is correct that the hydrocaps would be counterproductive from a labor standpoint (64 batteries x 3).

Glad you guys are paying attention, apparantly I'm not!

Jim, sounds like you're a veritable test bed e.g the Outbacks.  Do you monitor your new equipment with laptop download?  Just curious.

Image of stacked inverters.  The fly swatter is a little low tech cowboy humor.

crewzer

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Jim, sounds like you're a veritable test bed e.g the Outbacks. Do you monitor your new equipment with laptop download? Just curious.

Mangas,

I occasionally conduct tests and/or evaluations on equipment from a couple of companies. The equipment (HW and/or SW) is typically either loaned to me or I buy it, and I keep my work independent this way. I've had some equipment offered along with a preset protocol, but I declined due to the lack of independence. I have a laptop plugged into my system's Mate, but I rarely use it for data logging. Most T&E observations are instead made with pen and paper, and reports and evaluations are transmitted via e-mail. My key piece of "real" test gear is a Fluke model 189 multimeter... now that's a sweet piece of equipment! 8-)

I like your picture!

Regards,
Jim / crewzer

Mangas

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Interesting.  I'll bet the manufacturers are standing in line. The solar magazines ought to run "Road Tests" like the auto mags do.

This site should be a best practices must for people designing/building systems. 

Mangas

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Apparantly, they no longer offer the MX60 Controller fan kits. I guess you have to buy a whole new unit if it goes down.

Windsun

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

As far as the MX60 goes, we have sold probably 9,000 to 10,000 of them, and during all that time have gotten one back for warranty.

We have had a small number of the Xantrex inverters go out, but as far as we can tell, every single one was due to either lightning or "user malfunction" - like the guy that plugged 115 VAC into the battery terminals...

No, that was not under warranty

Mangas

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Thanks Windsun.

Jim also said their reliability is pretty good but your stats really are impressive. Probably why they don't offer the fan kits anymore.

115VAC into the battery terminals! Mercy.

rplarry

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Mangas
Did you check with Outback about the fan for the MX60? I find it hard to believe that there is no replacement fan for the MX60 any longer. My fan failed a few months after I got mine and they sent out a new fan and instructions for its replacement. I just told them that I had a "noisy" fan, sounded like bearing chatter as the fan rotated. Call them and see what they say.
Larry

crewzer

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Mangas,

I checked with OutBack re the MX fan issue. My contact assured me that their fan replacement program is "alive and well". 8)

HTH,
Jim / crewzer

Mangas

Re: Outback Charge Controllers/Xantrex SinePlus Inverters Longevity

Hi Jim,

Thanks very much for lining that out.

The info I received was from my installer. I don't know who his supplier is but I'll find out and we'll pass this on to them and order the kit.

Incidentally, we've been running both central A/C units thermostat at 80 F days/78 F Nights (hot humid days up to 105 F and summer rains with overcast afternoons) and the voltages are still 49 DC at sun up. The standby generator hasn't come on yet except its short test cycle.

Hope we can keep this performance level up.