Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds

I am working on a SW4024 that is connected to a generator. All power parameters are well within spec. The unit starts the generator, waits the usual time, then connects the battery charger (in steps so as not to bog the genset) and begins to charge the battery. After several minutes it suddenly drops the load from the genset, the power in the house blinks off momentarily (enough to annoy everyone) and it goes through its normal wait time and loads the genset again. There are no fault codes but I have not been able to run fast enough to see if there are any codes while the problem is actually occurring. I do not know if fault codes are ever stored in this unit.

It seems to me that with the momentary power interruption that the unit is experiencing some kind of reset. The Trace place in Portland had it and said they saw no trouble and the power relay looked good. This only happens when initially loading the genset and never when running from battery.

I suppose the answer is to replace the unit but I want to be double extra sure....

Comments

  • NorthGuyNorthGuy Posts: 1,925Solar Expert
    Re: Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds

    It is very common for the inverter to drop a generator if it doesn't like the quality of power that the generator produces.

    You can widen the tolerance parameters in the inverter, which will tell it to accept wider variation from the generator. Otherwise, you probably need to check if there's something wrong with the generator.
  • mcnutt13579mcnutt13579 Posts: 47Registered Users ✭✭
    Re: Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds

    No fault codes are showing after it has been dropped but then reconnected. Is this normal? I have not been able to get to the inverter fast enough to punch up the faults menu when it is disconnected.

    The generator is running a steady load and it is only dropping after several minutes of steady running. The generator is running at 60.0 Hz on the button and 115v at the terminals of the charger.

    Where are the tolerance settings? I did not see a menu for that, but I have not been through it with a fine toothed comb.

    Also, since this unit runs the generator in parallel with the inverter, I think that the fact that it is blinking the house power off whenever this happens is an indication that the unit itself is at fault, but I need to confirm this.
  • NorthGuyNorthGuy Posts: 1,925Solar Expert
    Re: Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds
    No fault codes are showing after it has been dropped but then reconnected. Is this normal? I have not been able to get to the inverter fast enough to punch up the faults menu when it is disconnected.

    The generator is running a steady load and it is only dropping after several minutes of steady running. The generator is running at 60.0 Hz on the button and 115v at the terminals of the charger.

    Where are the tolerance settings? I did not see a menu for that, but I have not been through it with a fine toothed comb.

    Also, since this unit runs the generator in parallel with the inverter, I think that the fact that it is blinking the house power off whenever this happens is an indication that the unit itself is at fault, but I need to confirm this.

    I don't think there would be error codes for dropping generator. The blinking is the result of transfer from generator to SW. It sees something wrong with generator, drops it and switches to the inverter. I don't know where tolerance settings are on SW, I have a different model - XW.
  • SkiDoo55SkiDoo55 Posts: 414Solar Expert ✭✭✭
    Re: Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds

    Looking in the manual for the SW looks like max setting for generator support is 24 amp. Range 4-24 amp. Set to match continuos rating of generator. Looks like input frequency range is 44-70 Hz. It may be trying to use too much from generator and voltage may sag. Would have to monitor/record during the event to capture it. Voltage regulator may work - stabilize after a few minutes. Of running. Charge star of batteries can contribute to high loads. Will ramp up and down to try and not exceed generator support setting.
    GT3.8 w/4600W Trina 230W, TX5000 w/5000W ET-250W, XW4024 w/1500W ET-250W, 4 L16, 5500W Gen. (never had to use) Yet!!
  • Ralph DayRalph Day Posts: 867Solar Expert ✭✭✭✭
    Re: Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds

    I had much the same problem with my SW4048. Was told that "our product wouldn't do that" etc etc. "If it's not charging right then it wouldn't invert right" blah blah blah. Well, then one dark December night suddenly no invert operation either! Kept alive by running the genset every 6 hours for 2 hours or so, didn't lose fridge or freezer and had a 12v inverter for one lamp and extension cord.

    Turned out, upon repair, that there was a problem with a 35amp relay IIRC. Replaced, re-installed and still working 8 years later. I wondered how many of those faulty relays were put through production/assembly...maybe at least 1 more:confused:. It might be next to impossible to get repair work done on an SW unit now, but search around, you might find someone who does some. And it's a scary feeling when the power goes out, and you're the power company!

    Ralph
  • mcnutt13579mcnutt13579 Posts: 47Registered Users ✭✭
    Re: Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds

    Thank you for that information. I suppose that an easy way to try and test/fix this would be to swap the power relays as there are two of them. I can't see pouring a bunch of money into this unit seeing how old it is.
  • Blackcherry04Blackcherry04 Posts: 2,486Solar Expert ✭✭✭
    Re: Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds
    Thank you for that information. I suppose that an easy way to try and test/fix this would be to swap the power relays as there are two of them. I can't see pouring a bunch of money into this unit seeing how old it is.
    You can fold up a piece of emery cloth and clean up the contacts. You must be able to get the plastic cover off as they will do that at the Inverter service center close to me. I have never watched them do it though.
  • techntrektechntrek Posts: 1,366Solar Expert ✭✭✭
    Re: Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds

    Sounds like the initial loading by the charger along with your household loads may be exceeding a parameter or actually causing an overload (this is more likely since it happens after a few minutes, after heat has a chance to build up). You get a good surface charge after the first few dropouts and after that the charge rate probably drops below the overload level, keeping the inverter online. I would first try reducing the amperage setting coming from the genset.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • VicVic Posts: 2,906Solar Expert ✭✭✭✭
    Re: Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds

    Couple of things ...


    None of the Xantrex SW or SW+ inverters that I have seen will indicate just why the genset is dropped.

    So, assume that the generator is connected to AC2 NOT AC1.

    Is the genset the only charge source at the time that the genset gets dropped? ie, NO Solar or Hydro charging going on?

    What is the nature of the genset?

    At times, if there is a significant amount (relative to the size of the genset) of charge power from a source other than the genset, the SW inverter can get dropped. This is most common when the SW is trying to regulate charge voltage.

    Suppose the most likely culprit might be a cold genset, (unable to handle full load), or as techntrek mentioned perhaps some downstream loads.

    Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • mcnutt13579mcnutt13579 Posts: 47Registered Users ✭✭
    Re: Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds
    Vic wrote: »
    None of the Xantrex SW or SW+ inverters that I have seen will indicate just why the genset is dropped.

    I am sure you have more experience than me with this (I am a generator guy) but I find it a little flabbergasting. How is anybody supposed to diagnose problems if it won't tell you what the problem is?

    The genset is a 10k diesel that is loafing. We have already dropped the charge current and it seemed to work for a few weeks but then the problem returned. As I recall, the amperage is around 24 on 120v and the well pump is like 8 amps. Voltage on the leg the inverter is on is 115 at the inverter and 124 on the other leg. Frequency is 60.0 on the button and I was looking at the frequency meter one time (my own Fluke clamp on) when it dropped once while completely warm and chugging right along.

    There is solar charging going on at the time. I will have to eliminate that the next time I try it out.

    One clue that I don't think should be ignored is that when it drops the generator, the power to the house dies momentarily (less than 1 second) but makes the TV go off, smoke alarm beep, etc. This makes me suspect the brain. One thing I did not try was to open the generator to charger input breaker while charging and see if this is normal behavior or a true problem.

    I guess some kind of time recording amp/voltmeter might help with this, but I doubt that is the problem.

    All experiences and thoughts and speculation welcome.
  • VicVic Posts: 2,906Solar Expert ✭✭✭✭
    Re: Xantrex SW4024 Drops Load Repeatedly, Then Finally Holds

    Hi mcnutt,

    Have little to add...

    1. So, this may be a new to you Inverter? More info on its history might help.

    2. Because you are a "generator guy", does this mean that you are new to battery/inverter/genset systems?

    3. I have little experience with the SW inverters -- use SW+es here, which have some added settings etc. Have no SW manual.

    4. There be an Error Causes menu -- menu #5 in SW+, which might note something. Although, an Error light would be lit if that was the case, I believe.

    5. The genset should be connected to AC2 terminals in the inverter, or in the Conduit Box, unless it is an Inverter generator (unlikely for your 10 K diesel).

    There could be an issue with the Inverter/Charger. Normally transfer to/from inverter takes one cycle or less. Some AC loads are very sensitive, such as fluorescent lights, some TVs etc.

    It is possible that a large load switching on or off could cause the genset's voltage to go out of range, and get dropped. It is somewhat less likely that a large load change could drag the frequency out of range and cause the drop.

    One also wonders about the battery bank as well. Are the batteries fairly healthy? ALL connections tight?

    Guessing done for now. But more general info on the power system and components sure would help eliminate some of the guessing.
    Thanks, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • mcnutt13579mcnutt13579 Posts: 47Registered Users ✭✭
    Just an update for you all 5 years later.  The one arm disconnect on the 4/0 DC wire, that is like nothing installed nowadays, was going bad.  Found it a couple years after I posted this thread.  Opened the box and it was burned and crunchy plastic.  (We had managed to get it working by moving loads across phase legs and playing with voltage setpoint before finding this.)  Replaced with a modern disconnect and does not ever glitch any more. Mysteries abound but sometimes you stumble on the answer.
  • BB.BB. Posts: 27,882Super Moderators, Administrators admin
    Nice to hear... Going back to basics (taking covers off of all connections, boxes, panels) and looking for something that does not look right (overheating, corrosion from water, etc.) will sometimes find the basic/intermittent problems.

    I had a few teaspoons of water that came in through my utility weatherhead. In one home, the water got to the main breakers/bus bars in the panels, and need replacement. In another home, the water got to the Meter Socket and corroded the main copper cable to binding screw connection and made the socket intermittent/and random disco lighting in the home.ill

    Had to "break the utility seals" to see the problems for both--Utility did not really care/make any big deal (I reported and they eventually came back to re-seal).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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