Xantrex System Failures

glasstone2

Re: Xantrex System Failures

mike95490 wrote: »

No need to disconnect any inverters for your load test, 12KW load, is still only a 12.01KW load on the batteries. If some of the inverters have not engaged (are still in idle) they wont load the system down. You need to do as much real-life testing as you can because once they think you are happy, they are going to vanish, and not come back. As everyone else is saying, the battery bank is way too small.
my single 6048 ran a 7kw floor sander for 2 days, with a 41KWh battery bank, and 3 KW of PV feeding it, the contractor finally had to rent a 12KW generator to run the sander while my system recharged for 2 days.

We have, in fact, run this exact test (all 4 inverters with a ~12kW-14kW load). Typically in this range we get the fault warning followed in a few seconds by the F48 Under Voltage error.

Using our appliances etc. as the load is too variable for a proper, controllable, repeatable test. We have told the Installer to bring their own load(s) and leave us on the grid while they play with their loads until they can demonstrate an operational System at full load (yeah, I see from reading this forum that this is likely a pipe dream) with their loads. Then and only then, will we try the system with our real loads...appliances and all. This is easily doable by the way they have wired up the connection to our house; they might have to install some 240V/120V plugs at one panel where the Solar Power System comes together from the Inverters.

YehoshuaAgapao

Re: Xantrex System Failures

Unfortunately, the guys yesterday had not talked to the guy who came out the previous day so there was considerable repetition of failures. At least the guy on the first day updated the firmware in the Inverters; it took him 3 hours to do that. The mode I have called "Perpetual Motion" (one Inverter charging the batteries from the output of the other three Inverters running solely on batteries) occurred on both days. The bunch yesterday insisted this is normal despite me explaining the first 2 Laws of Thermodynamics to them several times. Finally, they called Xantrex, and the Xantrex Tech had them reconfigure the System to make the Inverter that was spuriously charging the batteries the new Master. The Tech claimed that the Inverters have variations in sensitivity to the battery voltage, and that Inverter had gotten confused and thought it was grid-tied--it was trying to charge the batteries from the grid. I'm not comfortable with this solution as it seems to be jury-rigged. I'm afraid that aging of the Inverters will cause another slave to think it is grid-tied and try to charge the batteries from the output of the other Inverters. I don't see how with proper wiring this could happen. The installers think this is a permanent fix; I'm afraid that it is only temporary.

Are you sure the AC wiring is correct (if you're off grid, you should have nothing on AC1 any inverter)?. This could very well be an bug with the AC coupled battery bank support which allows Xantrex XW inverters to accept backfed input from AC-out to charge batteries (the backfed current would normally be from a grid-tied inverter such as Enphase or Fronius or Xantrex GT, for retrofitting grid-tie system to have a battery backup), but first be sure you don't have any AC-out connected to AC-in. The jumper bars in the PDP can be confusing and require above average IQ on the installer's part.

I have not been successful in getting these guys to actually look at the battery banks. I cannot even get them to measure the DC current coming out of the battery banks during the tests (my clamp-on multimeter is only AC -- I need to find a good DC clamp-on one)! Then one of these guys tried to convince me that my 24kW bank of XW Inverters is really only capable of delivering 20kW and that is 90A to the house. I was very, very tired and not inclined to discuss that.

You need somebody with a higher IQ and better training to help diagnose your problems (or somebody who is willing to take lots of time time, read the manual - xantrex has great wiring diagrams, research online, and learn learn learn). There are cheap not so ergonomic made in china AC/DC clamp meters available.. Get yourself one and you can help fix your own problem and save on service calls later. And a hydrometer too if you don't have one. I like the EZ-Red. though the purists on here like traditional and glass like this one but I find the EZ-Red a lot easier to use. You may need these if your installer is 'full service' and your batteries are badly sulfated - to get them to buy you a new battery bank (if you have battery issues). A full service installer should be emphasizing your need of a hydrometer and the need to water the batteries over and over again.

YehoshuaAgapao

Re: Xantrex System Failures

We have, in fact, run this exact test (all 4 inverters with a ~12kW-14kW load). Typically in this range we get the fault warning followed in a few seconds by the F48 Under Voltage error.

Using our appliances etc. as the load is too variable for a proper, controllable, repeatable test. We have told the Installer to bring their own load(s) and leave us on the grid while they play with their loads until they can demonstrate an operational System at full load (yeah, I see from reading this forum that this is likely a pipe dream) with their loads. Then and only then, will we try the system with our real loads...appliances and all. This is easily doable by the way they have wired up the connection to our house; they might have to install some 240V/120V plugs at one panel where the Solar Power System comes together from the Inverters.

You either have sulfated batteries or undersized battery wiring, probably both. You are pushing up to 520A (1040A at full surge load) over one or two cable sets. 4/0 is insufficient. 500KCMill will fit in 2.5" conduit. If you don't plan on using surge capacity and don't have a city inspector to worry about, 500KCMil will work, assuming you have 2 inverter cable sets.

inetdog

Re: Xantrex System Failures

Blackcherry04 wrote: »

Then you also have the " Coup De Fouet ", Dip and Recovery when your slamming loads on.

* " Circuit or system designs which subject the battery to repeated "coup de fouet" (whiplash) effects. This effect is a temporary, severe voltage drop which occurs when a heavy load is suddenly placed on the battery and is caused by the inability of the rate of the chemical action in the battery to accommodate the instantaneous demand for current. "

The references I have seen indicate that Coup de Fouet will only occur on a battery which has been brought to full charge and not loaded down or left to idle for any great length of time before applying the large load. If you are at 80% SOC, the coup should not be noticeable, only the voltage drop from internal battery resistance as the turn-on surge of the load passes.

YehoshuaAgapao

Re: Xantrex System Failures

They went on the roof and cut out the panels (the Charge Controllers switched to display insufficient light)

This is a sign of possible idiot, depending if they were tinkering with the PV wiring connections in the PDP or junction boxe(s). PV supply to the charge controllers can be shut down in the PV DC breakers in the PDP. Much easier than going up on the roof and turning off the breakers in the combiner boxes (assumption). If they were tinkering with PV wiring connections, then it would be very wise to shut down the PV at the combiner boxes.

Not all cities require easily accessible DC disconnects. In cities with no permits/inspections (or not in a city at all) many won't bother (I didn't - would need a disco for each combiner - too much extra cost). DC disconnects are good for improved firefighter service though. A firefighter won't fight a fire where he thinks he will get electrocuted - they will let it burn. This is why most cities require PV-DC disconnect (Midnite solar sells Disconnecting combiners though the birdhouse versions are expensive, the handle-only versions aren't that bad). In this case, if testing only, the PV breakers in the PDP are actually the most convenient.

ChrisOlson

Re: Xantrex System Failures

glasstone2 wrote: »

We have, in fact, run this exact test (all 4 inverters with a ~12kW-14kW load). Typically in this range we get the fault warning followed in a few seconds by the F48 Under Voltage error.

Do you know what the LBCO is set to? Is it still the default 47? I'd set that to a suitably low value like maybe 44. Then try it again with just two inverters. If those batteries, from 100% SOC, can't keep two inverters lit with the voltage sagged to 44 under load, then you got a battery or battery cable problem someplace. At 12 kW it should only be about 130 amps from each string.
--
Chris

Edit: excuse me, the default is 46. Try setting that down to 40 and set the LBCO Delay to 600 seconds. Then try it with two inverters at 12 kW load and see what happens.

glasstone2

Re: Xantrex System Failures

ChrisOlson wrote: »

Do you know what the LBCO is set to? Is it still the default 47? I'd set that to a suitably low value like maybe 44. Then try it again with just two inverters. If those batteries, from 100% SOC, can't keep two inverters lit with the voltage sagged to 44 under load, then you got a battery or battery cable problem someplace. At 12 kW it should only be about 130 amps from each string.
--
Chris

Edit: excuse me, the default is 46. Try setting that down to 40 and set the LBCO Delay to 600 seconds. Then try it with two inverters at 12 kW load and see what happens.

I asked Monday (the first of the last two tests), and it was set at 44V. I checked for all the tests yesterday, and it was still set at 44V. The installer guys told me that that is the lowest setting. When we had a voltmeter connected (and/or the Control Panel will display it), we watched the voltage quickly drop to 44V where the red fault lights begin flashing. Then it dropped below 44V, and the F48 fault appears briefly, and the System crashes dumping the load.

NorthGuy

Re: Xantrex System Failures

glasstone2 wrote: »

I asked Monday (the first of the last two tests), and it was set at 44V. I checked for all the tests yesterday, and it was still set at 44V. The installer guys told me that that is the lowest setting. When we had a voltmeter connected (and/or the Control Panel will display it), we watched the voltage quickly drop to 44V where the red fault lights begin flashing. Then it dropped below 44V, and the F48 fault appears briefly, and the System crashes dumping the load.

What is the batteries voltage at rest (when there's no loads and no charging takes place)?

glasstone2

Re: Xantrex System Failures

NorthGuy wrote: »

What is the batteries voltage at rest (when there's no loads and no charging takes place)?

The batteries are currently at 51.3V. Before the load tests which was supposed to be 24kW but we only got to 12kW-16kW depending on the test, the batteries started at 56V for most tests or 54V or a few. I cannot get a case with no charging as we never made that measurement.

glasstone2

Re: Xantrex System Failures

Minor UPDATE:

Now the installer guys are telling me via email: "We need to equalize the batteries, then make sure they have a full charge to start with. Schneider recommends using the generator to keep the cycle steady, and I'd like to run it through Thursday night. That will set us up with a completely topped off bank Friday for the load testing."

I hope this is not indicating a change where we are supposed to run the generator frequently as part of our system--a generator electric supply system with a solar backup.

ChrisOlson

Re: Xantrex System Failures

44V is a reasonable setting for LBCO. But it will go down to 40, I don't care what your installer claims.

It shouldn't sag that low with fully charged batteries, though. What I would do is set it to 40, set the delay at 600 seconds, then load the system to 12 kW and keep track of the voltage at the inverter studs with a DVOM just to see how low it really does go. There's no reason those two battery strings can't deliver 130 amps each for at least a half hour and hold the voltage above 40. If they can't then you got a battery problem (besides not having enough capacity).
--
Chris

ChrisOlson

Re: Xantrex System Failures

glasstone2 wrote: »

Now the installer guys are telling me via email: "We need to equalize the batteries, then make sure they have a full charge to start with.

Really, I'll put this the most gentle way I know how;
Your installer(s) don't have a freaking clue.

Before you even THINK about EQ'ing those batteries - they are at a decent at-rest voltage right now. The first thing I would do break out the hydrometer and check the SG to find out if you have a dead cell or two. You don't equalize batteries just because. The hydrometer is the only tool that will tell you if they need it or not.
--
Chris

NorthGuy

Re: Xantrex System Failures

glasstone2 wrote: »

The batteries are currently at 51.3V. Before the load tests which was supposed to be 24kW but we only got to 12kW-16kW depending on the test, the batteries started at 56V for most tests or 54V or a few. I cannot get a case with no charging as we never made that measurement.

You can look at the voltage after dark. They won't be charging. If you remove loads and wait half an hour they will be at rest. If you still get 51V, your batteries are charged.

Fully charged batteries should not sug to 44V under 16kW load. If they do, then either something is wrong with the batteries or something is wired incorrectly.

It is a good idea if you insist on them measuring specific gravity of the batteries with hydrometer once they're charged. You can do that by yourself too. Each cell needs to be measured. If specific gravity is less than specified by manufacturer or different between cells, then you have a problem with batteries which needs to be addressed before everything else.

Cariboocoot

Re: Xantrex System Failures

And by the way, you charge the batteries first then see if they need equalizing. Practically impossible to do it the other way 'round.

glasstone2

Re: Xantrex System Failures

INSANITY UPDATE

I told my contractor that the Installer company will have to bring their own load(s) (e.g. 10kW Heaters etc.), and demonstrate a fully working System at full power (24kW). This testing would be done leaving our house on the grid; because of the wiring from the Solar Power System to our grid-cut off (the gird does not feed the Inverters at all) this is easily doable and spares our appliances etc. further risk from the Inverter crashes. While I view this as reasonable (I'm not a Lab Rat for the installers.), apparently the Installer company did not as I got some curious responses from their main Installer guy:

"The system IS performing as it should, even with the erratic inverter. There are a couple settings to change in the generator controller, and another shot at getting the firmware not just compatible, but consistent."

Given what I have described on this Thread, I can only call the above quote insane. There is more in a similar vein in their email, but I'm not going to trouble you with it. It appears that a technical solution is no longer likely in this case, and I'll have to look for another solution.

I am grateful for all the advice, tips, and even sympathy from the posters on this Thread. You probably don't know how helpful you have been. When this mess is over, I hope to build a proper system from scratch, and I may be on this Forum again asking for your expertise.

Thanks again!

P.S. I think by "erratic inverter" he means the case where 3 Inverters are supplying AC power solely from the batteries while the 4th Inverter is using that AC output from the other Inverters to charge those very same batteries. See the Perpetual Motion mode in my previous posts.

ChrisOlson

Re: Xantrex System Failures

Gosh, I feel bad for you. That would be an awesome off-grid system, properly set up. I don't have much faith that your current installer(s) are going to arrive at a way to get it working though.

Is there a chance that you can take the project over yourself and fix everything they that got screwed up? It shouldn't be that hard to fix it once you get that Perpetual Motion inverter rewired (just change the AC input on it to the gen), and you'll have to buy two more strings of batteries (and verify that the ones you got are really good). They evidently have the Power Distribution panels all installed and wired up, and the gen wired, and the solar installed and operating.

The main thing that I'm wondering is, do you really need four inverters? Why can't you use just two with generator support for peak loads? Two inverters are easily enough to meet your daily kWh requirements, but they probably can't carry peak loads. But with generator support (which takes very little fuel cost in comparison to two extra inverters and the required batteries to power them) I can't imagine it would not be doable. Did anybody think of that?

It is one of those deals where what you have endured so far is so insane from failure of the installer to even know the equipment and the basics of how to design an off-grid system that it's frustrating. We run our 30 kWh/day off-grid home here with just one XW6048 and generator support for peak loads. I can't imagine why it would not be possible to run a 60 kWh/day home with two of them and a bigger generator. When you put the pencil to it all, running the generator for the peak loads is way more economical than buying the extra solar, batteries and inverters for intermittent heavy loads. And your installer evidently does not know that.
--
Chris

glasstone2

Re: Xantrex System Failures

ChrisOlson wrote: »

The main thing that I'm wondering is, do you really need four inverters? Why can't you use just two with generator support for peak loads? Two inverters are easily enough to meet your daily kWh requirements, but they probably can't carry peak loads. But with generator support (which takes very little fuel cost in comparison to two extra inverters and the required batteries to power them) I can't imagine it would not be doable. Did anybody think of that?--

Last November, after this bunch presented up with a completed too-small system for our load analysis (they admit that they did not even look at the list of appliances etc. with rated kW numbers that we compiled and gave them well before the system was designed), we asked if the battery banks could handle the peak loads for 3 or 4 inverters to get us to a realistic electrical supply. The installer company assured us more than once that those 2 banks of batteries could with an upgrade to the cabling. As a result, we trustingly decided to spend the relatively small extra funds to get the 4 inverters rather than 3. We were misled flat and simple. Now that we are waking up to reality, we have begun to ask questions and demand that they show results. They in turn are backing off on the language in the contract and telling us that we have to settle for much less than what we paid for. This is why the current system has 4 inverters and cannot even reliably support 12kW continuous load.

No one has said anything about using the generator to pick up the peaks which I admit seems to be an attractive and plausible solution. In fact, when they installed the generator we were expecting a 12.5kW one, but they decided that only an 8.5kW was required without consulting us. We protested to no avail. Moreover, the Kohler generator is much much noisier than advertised, and they are ignoring us on that question too.

These people are completely resistant to change, and when confronted with obvious failure declare that the system is working correctly. You got a small taste of this with the assertion that I quoted. This sort of assertion is not uncommon in our dealings with them.

Thanks for your advice and the good idea. Depending on what kind of resolution we get to in the next few days or weeks, perhaps I can see about implementing your suggestion.

ChrisOlson

Re: Xantrex System Failures

This here thread was started by me to show folks how generator (load) support works, and what it can do for you for peak loads when you're off-grid.
http://forum.solar-electric.com/showthread.php?18459-Demonstration-of-Generator-Support

It was done with our old 5548 before we got the XW. But it works the same with the XW. I started the thread because not enough people use the feature (and some don't understand what it does). IMHO it is one of the most useful features of an off-grid inverter for folks who want to be able to power large (and what are usually nice conveniences to have) loads with an off-grid system, and not break the bank to do it.

Have your installers watch that video and ask them to explain why they never bothered to set up your system to use it. You have a system there that is fully capable of using this feature. It requires your battery bank to only carry the heavy load for a short time and then the generator helps out to reduce the load on the inverter and batteries to make life easier for them. And when the load goes away (drops below the threshold setting), it shuts the generator off. It's basically on-demand peak load power automatically supplied by your generator.
--
Chris

westbranch

Re: Xantrex System Failures

There is a great thread about Chris' system for Gen Support here:http://forum.solar-electric.com/showthread.php?18459-Demonstration-of-Generator-Support&highlight=generator+support

rats, Chris types faster than I do

mike95490

Re: Xantrex System Failures

It may be you will have to end up in court to get your $$ back, and have the job completed right.

First off, BE SURE the battery bank is charged properly. Sucking all that power out, I hope it's not damaged from
insufficient charge. It's an easy to replace item, but expensive!

If the install company has completely failed so far, watching the video, is not likely to raise their IQ's. It may be
that you will become the expert. You may need to fly somebody (does NAWS have any staff that can make road trips?) in
to get it sorted out.

I've been watching this thread for a while. But even with a big stick, you can't fix stupid. You may have to abandon
the "contractor".

YehoshuaAgapao

Re: Xantrex System Failures

Have your installers watch that video and ask them to explain why they never bothered to set up your system to use it. You have a system there that is fully capable of using this feature. It requires your battery bank to only carry the heavy load for a short time and then the generator helps out to reduce the load on the inverter and batteries to make life easier for them. And when the load goes away (drops below the threshold setting), it shuts the generator off. It's basically on-demand peak load power automatically supplied by your generator.

I thought generator support was the opposite - to use the batteries to support an under-sized generator (like his - 8.5KW gen vs 24KW worth of inverters) in powering the loads?

You can program AGS to start and stop the generators with certain load thresholds. I have mine setup this way. If there is more than 1.5KW while off-grid, run the generator. When it drops below 1.0KW, stop it (1280 watts will last 18 hours at 60% DoD at full capacity). Charge block (inverter) and quiet time (AGS) can keep the generator running during solar production hours. This is configured through the AGS, not the inverters.

ChrisOlson

Re: Xantrex System Failures

YehoshuaAgapao wrote: »

I thought generator support was the opposite - to use the batteries to support an under-sized generator (like his - 8.5KW gen vs 24KW worth of inverters) in powering the loads?

It works either way. Typically the Load Amps setting will start the generator because the inverter or battery bank is overloaded. The generator starts and goes to full load and the inverter helps the generator out. But if you look at it from the other side, the inverter was overloaded and called for help from the generator. So the generator is helping the inverter out.

The key is not using a generator that's too big. The whole purpose of using the feature is that you can use a smaller generator that is fully loaded charging batteries so you get peak efficiency from it during battery charging. But that generator is not big enough to carry the peak loads by itself. With both the generator and inverter power combined, the peak loads can be met. This saves you money on batteries, extra inverter capacity, and the RE charging capacity to charge those extra batteries - which you would all have to have to operate that intermittent peak load - and the rest of the time sets there not being used.

There's a lot of folks that still don't understand its value. But the "rule of thumb" I have developed in experimenting with it and implementing it is that you know what your peak loads are. You don't size an off-grid system like they do grid systems. Grid systems (200 amp service) is designed so you can run around and flip every switch you got and turn it all on at once. In reality that just doesn't happen. So come up with a peak power rating that represents your normal habits - what stuff is normally running and what other stuff can be normally turned on to cause the worst case scenario without running around and turning stuff on just to see if it blows.

That's how much power you need. The inverter and generator together should be able to supply that peak load power, with both at full load, and maybe throw in a 10% reserve from what you arrived at above for your peak power needs. The generator needs to be sized to either:
- provide enough amps from the inverter charger to supply a C/10 charge to the battery bank
- provide enough power to operate the inverter's charger at full rated output
whichever is smaller.

If you keep shuffling the numbers you arrive at a size for your generator and inverter that will work with your loads with generator support. And if you can get by with an even smaller generator than what I describe above (our situation here) simply because the generator is used primarily for load support and hardly ever charges batteries, IMHO that's even better yet. Smaller generators are more efficient and cheaper to run. Any time you have a generator running with unused capacity, you are losing ground feeding cubic inches that are doing nothing for you.

So that's what I've figured out with it thru first learning how to use it, then implementing it and fine tuning it. Not many folks use it - it seems the general idea is to keep throwing more solar panels, more inverter power and more batteries at off-grid systems so the generator doesn't have to run. Somehow, somebody came up with the idea one day that never running the generator is the epitome of off-grid. It might be, but using the generator for peak loads is way cheaper
--
Chris

Vic

Re: Xantrex System Failures

glasstone,

It appears that your batteries may not be getting fully charged. And perhaps they have never been.

Others have mentioned it, BUT, do not recall that you indicated that you have actually measured the SG of each cell with your Hydrometer. Even measuring a few cells would help, but soon every cell needs to be measured and recorded in that Battery Logbook.

One additional point. This is a fairly young system;
Battery Capacity on a new bank is built from cycling the bank to 50 or 60% SOC some number times, preferalby early in the life of the battery bank(s).

Doing a load test on banks that have not been significantly cycled may well be a waste of time.

Have the batteries used ANY water yet, ... hope that you have checked. IMHO, the heath of your batteries needs to be monitored by YOU. Would you trust the installer folks to do that for you??

Opinions, Good Luck, Vic

ChrisOlson

Re: Xantrex System Failures

ChrisOlson wrote: »

So come up with a peak power rating that represents your normal habits - what stuff is normally running and what other stuff can be normally turned on to cause the worst case scenario without running around and turning stuff on just to see if it blows.

I am making a quote to my own post because I believe that is what is going on with the OP's situation in this thread. Does the home actually pull 24 kW at any time? It would behoove anybody doing this to buy a Fluke AC clamp-on meter with high value recording capability and measure peak continuous and peak surge loads over at least a week's time to determine what they actually are. The Fluke meter is way cheaper than just throwing four XW6048's at it because you added up a bunch of loads that you think you might run all at the same time one day - and you're using nameplate values off the loads which rarely applies in the real world.
--
Chris

YehoshuaAgapao

Re: Xantrex System Failures

Is there a chance that you can take the project over yourself and fix everything they that got screwed up? It shouldn't be that hard to fix it once you get that Perpetual Motion inverter rewired (just change the AC input on it to the gen), and you'll have to buy two more strings of batteries (and verify that the ones you got are really good). They evidently have the Power Distribution panels all installed and wired up, and the gen wired, and the solar installed and operating.

It wouldn't hurt to at least look at your jumper bars (manual calls them power distribution bars) in your AC breakers in your PDPs. If you are comfortable replacing a hard drive in a desktop/laptop, reseating or moving a wire to a nearby terminal is very similar (just larger screwdriver). Just don't do it while its hot (energized, power running through it) - amateurs need to play it safe. James who is not familiar at all with my system - he still doesn't fully understand how it works, also plays it safe around my PDP even though he works with main panels hot all the time (reduces power outage) because he has done so many residential panel upgrades as well as numerous new subpanels and generator ATSs in commercial sites (I'm perfectly ok playing it safe, just shut off the power. I'm not one of those customer that puts up major fit because the power goes out or is out too long).

The main thing that I'm wondering is, do you really need four inverters? Why can't you use just two with generator support for peak loads? Two inverters are easily enough to meet your daily kWh requirements, but they probably can't carry peak loads. But with generator support (which takes very little fuel cost in comparison to two extra inverters and the required batteries to power them) I can't imagine it would not be doable. Did anybody think of that?

Peak loads (motor starts) happen suddenly, too fast for a generator. The batteries are on their own for these. If it is a not a split-second peak load like 30 minutes on a dryer or 120 minutes on an oven, then generator-assist would work great for that. The hard load has to be on for at least a minute or two for the AGS trigger delay, generator startup time, and inverter's qualification delay to respond to it. You also need a properly sized generator and moolah for the gas that the bigger generator will guzzle more of even on low loads though (its an ongoing cost you can't get a gratitude-to-the-fed-printing-press cheap interest rate loan for).

Four Xantrex inverters is 24KW continuous, 48KW surge
Equivalent in outback radian 32KW continuous, 48KW surge (3 inverters is 24KW cont, 36KW surge).

A 200 amp main breaker can provide 38.4 KW continuous, 48KW surge with perfectly balanced legs. Your installer mostly likely thought after your complaining about load analysis 'you want the whole house off-grid without concern for conservation, lets get enough inverter output to handle the full load capacity of your main service panel'.

And remember, especially if you really do need 4 inverters, your battery and subpanel wiring needs to handle continuous amps *1.25 plus surge-difference amps * 1 and the grid (you don't have grid so not relevant) wiring needs to handle 60A per inverter (/1.25 is 48 amps) to be able to charge batteries at full rate and passthrough to loads simultaneously. Generator wiring needs to handle the generator's continuous amps * 1.25 plus the surge-difference amps * 1.

YehoshuaAgapao

Re: Xantrex System Failures

The key is not using a generator that's too big. The whole purpose of using the feature is that you can use a smaller generator that is fully loaded charging batteries so you get peak efficiency from it during battery charging. But that generator is not big enough to carry the peak loads by itself. With both the generator and inverter power combined, the peak loads can be met. This saves you money on batteries, extra inverter capacity, and the RE charging capacity to charge those extra batteries - which you would all have to have to operate that intermittent peak load - and the rest of the time sets there not being used.

There's a lot of folks that still don't understand its value. But the "rule of thumb" I have developed in experimenting with it and implementing it is that you know what your peak loads are. You don't size an off-grid system like they do grid systems. Grid systems (200 amp service) is designed so you can run around and flip every switch you got and turn it all on at once. In reality that just doesn't happen. So come up with a peak power rating that represents your normal habits - what stuff is normally running and what other stuff can be normally turned on to cause the worst case scenario without running around and turning stuff on just to see if it blows.

Maybe I will turn on generator support, but set it at 20-22 amps (at or near 80% of breaker rating), just to have it as a safety net.

My winter high-constant loads on the sub panel is 2KW (I don't have any 240V piggys on the subpanel and also the whole kitchen minus refrigerator is not on the subpanel). Summer will add another 2KW worth of swamp coolers and fans to that. Add 1KW to leg imbalance and short-term spikes, and there is still 1KW to go (0.5KW on the generator; generator will go to 6500W for 30min though breaker size setting will limit to 22A/5760W). When I ran my system off-grid for two days in february, my generator was pushing 2KW to the subpanel and supporting a 50-65A charge to the batteries. But who knows. Maybe some idiot will plug in an industrial strength hair dryer that they can't live without while operating off-grid. The only motors that need surge current is the fridge and the chest freezer. The swamp coolers have start capacitors in them (And they start up FAST - though loud, Port-A-Cool is AWESOME). Oh yea I forgot, my Patton high velocity fans also need surge current - they have 1/2 horsepower motors like the swamp coolers (1.5A on low, 3A on high; swamp coolers are the same, plus 1A for the pump) but start up much slower - no start capacitor. I have 2 of these swamp coolers and 2 of the fans. Both swamp coolers on at the same time but only 1 fan. My sister uses the ceiling fans which add up to 3-4A (3 rooms).

ChrisOlson

Re: Xantrex System Failures

I've found that the XW6048 doesn't seem to have much issues with leg imbalances, even with one leg overloaded. I have the load start set at 25 amps, and Load Stop set at 20 amps. But it has to be over 25 amps for five minutes before it will start the generator. And it won't stop the gen unless the load drops below 20 amps for one minute.
--
Chris

mike95490

Re: Xantrex System Failures

ChrisOlson wrote: »

....
The key is not using a generator that's too big. The whole purpose of using the feature is that you can use a smaller generator that is fully loaded charging batteries so you get peak efficiency from it during battery charging. But that generator is not big enough to carry the peak loads by itself. With both the generator and inverter power combined, the peak loads can be met. This saves you money on batteries, extra inverter capacity, and the RE charging capacity to charge those extra batteries - which you would all have to have to operate that intermittent peak load - and the rest of the time sets there not being used. ....

Exactly, folks went nuts when I said I was using 6hp 3Kw genset, they wanted me to buy & use (from any vendor) something in the 15KW neighborhood. So I just smile when in a cloudy week, I burn only 2 gallons of diesel.

mike95490

Re: Xantrex System Failures

YehoshuaAgapao wrote: »

.... My winter high-constant loads on the sub panel is 2KW (I don't have any 240V piggys on the subpanel and also the whole kitchen minus refrigerator is not on the subpanel). Summer will add another 2KW worth of swamp coolers and fans to that. ......

Uh, what the heck is causing 2Kw of loads in the winter - you are not using electric heat are you ??? What size is the house? If you are supporting 5 -8 folks, this may be more reasonable, but for 2 or 3, something is wrong here.

YehoshuaAgapao

Re: Xantrex System Failures

mike95490 wrote: »

Uh, what the heck is causing 2Kw of loads in the winter - you are not using electric heat are you ??? What size is the house? If you are supporting 5 -8 folks, this may be more reasonable, but for 2 or 3, something is wrong here.

Me, my sister, Josh (her boyfriend), and Jenna (niece).

The chest freezer and fridge add up to 4-7A when they are running (both energy star, 2-speed compressors). Living room when fully on (52" LCD TV, dish DVR, playstation 3, stereo, netbook computer, fish tank, ceiling fan, 2 sets incandescent lights (all are dimmable) is about 4 amps (5 when kitchen light is on - same circuit). The family room (my computer stuff - 18" high-end laptop, 32" & 22 LED-backlit LCD TVs, wireless router, printer, 1 or 2 netbooks, dish DVR) is 2A. Jenna's room is about 2A (35" CRT TV, dish network DVR, ceiling fan, fluorescent lights). Their room has a 19" CRT TV, ceiling fan, another fan, fluorescent lights, and a humidifier, about 3A. Get 1.8-2.2 KW when all the rooms are active at once (Jenna in her room, Josh sleeping in his room - fans & TV, Hope in the living room, me on the computer in family room). Hope and Josh use fans year round. I use more powerful fans but only in summer. When everybody is home, its about 1KW in the morning and 2KW at night (everything alive and active). If it is nobody home (or just me) its 0.5-1KW (depending on refrigeration run-state)

An electric heater all by itself is 1.5KW.