Repaired SW4024 settings?

stmarstmar Solar Expert Posts: 369 ✭✭✭
I just had my SW4024 repaired, the main AC transformer burned up/shorted. Has anyone else had this problem and is there a way to avoid it in the future? It happened after a 3 day grid outage and when the grid came back up it actually started a fire because the transformer got so hot, burned the paint on the enclosure. What settings are other owners using? I have a dozen solar panels, a small wind turbine, 4 Concorde AGM 255AH batteries. I use it mainly for backup for when the grid goes down, I do not sell power back to the utility company. Also does anyone know where I could pick up a 30 amp DPDT Nema-1 disconnect, ON-OFF-ON, non-fused? I could go with a 60 amp but all I can find is 100 amp, this will only be used for my well that I have on grid 240 volt but have the ability to use a step up transformer and the inverter power if needed, draws less than 15 amps.

Comments

  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Repaired SW4024 settings?

    Sounds like a transfer relay stuck and the grid cooked the guts.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • stmarstmar Solar Expert Posts: 369 ✭✭✭
    Re: Repaired SW4024 settings?

    Sounds plausible, is there any precautions to take to avoid a recurrence or is it just one of those things that happen?
    The main settings I was wondering about are the Bulk time (2 hours) and Charge Amperage (30A). Are these okay for my battery bank, 4 X 12 volt 255AH AGM Concordes. They are over 5 years old but I have had no issues with them.
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Repaired SW4024 settings?
    stmar wrote: »
    ... wondering about are the Bulk time (2 hours) and Charge Amperage (30A). Are these okay for my battery bank, 4 X 12 volt 255AH AGM Concordes. They are over 5 years old but I have had no issues with them.

    BULK is usually stopped by a voltage setpoint, then the absorb timer takes over. With AGM batteries, you HAVE to follow the factory specs for charging voltage and time.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • stmarstmar Solar Expert Posts: 369 ✭✭✭
    Re: Repaired SW4024 settings?

    For some reason I am having problems getting straight forward info on specs, anybody have a link to definitive info? It looks like I am in range with 28.8 bulk volt charging, 2 hour charge time and 26.8 float. The only time the bulk charge engages is after a grid power outage. Another thing I have noticed is that my voltage is fluctuating a few tenths when on float, in the past I thought it was constant at the 26.8 volts. Is this normal or is there a setting I have overlooked or am I not remembering correctly, it has been a while since I have had it up and running?
  • BB.BB. Super Moderators, Administrators Posts: 32,800 admin
    Re: Repaired SW4024 settings?

    What is dong the "floating"? The SW or a solar charge controller, other source?

    A few tenths of variation is probably not a big deal in float... As your DC loads change, you will see some differences in battery bus voltage and possibly some time delay in a response by the charge controller (there are different ways/reasons for designing control/feedback circuits and how quickly they respond to battery bus voltage changes).

    If the voltage drifts for a few seconds/minute then drifts back--It should be fine. Holding the battery at 26.8 volts in float +/- 0.1 volts is not going to improve battery life in any measurable amount (my humble opinion).

    If the voltage drops to 25.4 volts (12.7 volts @ 12 volt bank) or goes over ~27.6 volts (13.8 volts) for appreciable amounts of time (or at 120 Hz when looking at bus voltage with an oscilloscope), then you have reasons for concern.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • stmarstmar Solar Expert Posts: 369 ✭✭✭
    Re: Repaired SW4024 settings?
    BB. wrote: »
    What is dong the "floating"? The SW or a solar charge controller, other source?

    A few tenths of variation is probably not a big deal in float... As your DC loads change, you will see some differences in battery bus voltage and possibly some time delay in a response by the charge controller (there are different ways/reasons for designing control/feedback circuits and how quickly they respond to battery bus voltage changes).

    If the voltage drifts for a few seconds/minute then drifts back--It should be fine. Holding the battery at 26.8 volts in float +/- 0.1 volts is not going to improve battery life in any measurable amount (my humble opinion).

    If the voltage drops to 25.4 volts (12.7 volts @ 12 volt bank) or goes over ~27.6 volts (13.8 volts) for appreciable amounts of time (or at 120 Hz when looking at bus voltage with an oscilloscope), then you have reasons for concern.

    -Bill
    The SW is doing the controlling, at least that is my understanding: The status is Float once the battery bank has been charged and the charger (SW) keeps it there until there is a grid interruption. I powered it up yesterday and it went into Bulk mode and charged at 28.8 volts @ 30 amps for 2 hours and this charged the bank up and it now is in the 27 volt range and fluctuates plus or minus a few tenths as I stated before. I have the float set at 26.8.
    P.S. Just looked at it and it is holding steady at 27.1 volts with the solar array charging it at 17+- amps per my Pro-Star 30 controller. I have 4 12 volt batteries series and parallel to generate 24 volts, there is a one or two tenths difference in the volt reading between the batteries. Is that normal? This is not the fluctuation but a constant difference.
  • BB.BB. Super Moderators, Administrators Posts: 32,800 admin
    Re: Repaired SW4024 settings?

    Batteries do "care" about small voltage differences... Very roughly on a 12 volt battery bank a 0.1 volt difference is a 10% state of charge difference for a "resting" battery.

    To "equalize" AGM batteries... You just hold them at ~14.4 volts (your normal absorb voltage) for a few extra hours (watch that batteries do not overheat).

    Concorde specifically has some (very non-standard for AGM) equalizing instructions:

    Sulfated Lifeline Concorde AGM Batteries

    questions about conditioning/equalizing charge for AGM

    As always, be very careful when recharging batteries beyond normal limits--They can do very nasty things if there are other issues with the batteries/cells.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • stmarstmar Solar Expert Posts: 369 ✭✭✭
    Re: Repaired SW4024 settings?

    Don't you mean 1 volt would be 10% and 0.1 would be 1%? Or is "state of charge difference" a different calculation? My difference is a couple of tenths and could that be from the different measuring devices? My Pro-Star monitors the one set and another meter monitors the other set.
    I will try doing a few extra hours at the absorb rate. My solar array has been charging all day and the voltage is not jumping around like it was when I first energized the inverter. Thanks for the links, I will study up on Sulfated AGM's. Don't know if mine are, they have been on the solar array with only a frig as a load so they have never been discharged very much, maybe 10% discharge at most.
  • BB.BB. Super Moderators, Administrators Posts: 32,800 admin
    Re: Repaired SW4024 settings?

    It depends on the battery, but from hour Host's Battery Faq:

    http://www.windsun.com/Batteries/Battery_FAQ.htm



    [TH="width: 132, bgcolor: #FFFFFF, align: center"]State of Charge[/TH]
    [TH="width: 132, bgcolor: #FFFFFF, align: center"]12 Volt battery[/TH]
    [TH="width: 132, bgcolor: #FFFFFF, align: center"]Volts per Cell[/TH]


    100%

    12.7
    2.12


    90%
    12.5
    2.08


    80%
    12.42
    2.07


    70%
    12.32
    2.05


    60%
    12.20
    2.03


    50%
    12.06
    2.01


    40%
    11.9
    1.98


    30%
    11.75
    1.96


    20%
    11.58
    1.93


    10%

    11.31
    1.89


    0

    10.5
    1.75




    In the middle of the range, 80% SOC = 12.42 volts; 70% SOC = 12.32 volts.... That is what I was trying to convey.

    The graph would look like:
    BB. wrote: »
    New poster "leaf" has a really nice set of charts that compare battery voltage against different rates of discharging and charging (as well as resting voltage readings).
    leaf wrote: »
    Am trying to upload the charts I am using...

    Attachment not found.Attachment not found.

    attachment.php?attachmentid=3655

    attachment.php?attachmentid=3654

    [note charts are from: I believe those charts are from Home Power #36, August- September 1993. Lead-Acid Battery State of Charge vs. Voltage ©1993 Richard Perez.
    Here is a link: http://www.scubaengineer.com/documen...ing_graphs.pdf

    vtMaps
    ]

    I don't quite a agree with the resting voltage line (I think the voltage is a bit low)--But it shows how to estimate a battery's state of charge while operating.

    Note, where the charts "flatten out"--the room for error estimating state of charge is pretty high.

    -Bill

    And you are correct... It is not hard to have a ~0.1 volt difference between different measuring devices--And add voltage drop if there is current flowing.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • VicVic Solar Expert Posts: 3,171 ✭✭✭✭
    Re: Repaired SW4024 settings?

    stmar,

    And to satisfy curiosity, is your repaired inverter the older Trace/Xantrex SW4024, or the new Schneider Context SW4024? You did mention that your batteries were about 5 years old....

    And, are there circuit breakers on the Grid AC inputs and on the outputs? Did a breaker trip during this "fire"?

    There should be a transformer temp sensor on either of these inverters, which should greatly reduce the chance of this fire ever occurring.
    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.
  • stmarstmar Solar Expert Posts: 369 ✭✭✭
    Re: Repaired SW4024 settings?

    It is the older Trace it was purchased in 2002. It is fed from a 60 amp breaker from the grid and feeds a breaker panel for AC loads. Everyone I have talked to says that there should not have been a fire but there was, one guy with 15 years experience repairing these units said he had never heard of one catching on fire. Luckily I was there when it broke out because I heard the fans running and that was unusual. As one poster said it was probably a stuck relay that caused the main AC transformer to fry. I tripped the 60 amp breaker manually immediately so I don't know if it would have tripped or not.
  • stmarstmar Solar Expert Posts: 369 ✭✭✭
    Re: Repaired SW4024 settings?

    I have another question: Would it have any benefit, since this is an older battery bank, to modify the charge amperage, voltage and time for bulk and float charging values? I left them at factory defaults and it looks like these were in range with AGM battery recommendations:
    Battery bank consists of 4 X 12 volt Concorde AGM PVX-2580L
    Bulk = 28.8 volts @ 30 amps for 2 hours
    Float = 26.8 volts
    I have had no obvious problems to this point and will probably replace the battery bank in the not too distant future. I have also been advised to go with 6 volt AGMs instead of 12 volt.
  • BB.BB. Super Moderators, Administrators Posts: 32,800 admin
    Re: Repaired SW4024 settings?

    AGMs tend to be more expensive (!2x as much) as flooded cell batteries... Plus they may last a few years less than equivalent quality flooded cell batteries. Flooded cell batteries are nice because you can check/monitor their state of charge and health with a hydrometer/specific gravity measurements.

    AGMs don't use distilled water, have much less maintenance (no acid mist) and much better surge current. If you have gotten the life you needed and they meet your needs--More of the same is fine.

    A battery monitor (Victron is another good brand) can be very nice, and almost a necessity for AGM. Allows you to manage the State of Charge and loads more easily (Battery Monitors can "lie"/drift--So you still need to check battery voltages/make sure that the readings are correct).

    How many years did you get from this bank so far? If you got something like 5-7 years, you are doing very well and you should keep doing it.

    If battery capacity is important to you--You might try running the batteries down (no charging) for 1-2 days to 50% State of Charge to make sure they still have the minimum capacity for your needs (during bad weather, emergency, etc.).

    I really like a single string of batteries (with two to three parallel strings maximum, wired per this website and should have a fuse/breaker per string to protect against short circuits)--Less problems with current sharing and other issues. A DC Current Clamp meter is a very nice diagnostic tool. You check each string to ensure that they are reasonably sharing charging/discharging current. You will quickly find bad wiring and open/shorted cells before they cause more damage to the balance of the bank.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • stmarstmar Solar Expert Posts: 369 ✭✭✭
    Re: Repaired SW4024 settings?

    If I am reading the Concorde literature correctly I think the bulk and float are in spec, 28.8 and 26.8 respectively:
    Full charge termination voltage (ᤙ°C) 14.40 Vdc - I assume this is Bulk
    Float charge termination voltage (ᤙ°C) 13.40 Vdc
    So this value should not be changed even though the batteries have some age on them? I dropped the charging amps from 30 to 5, a repair center tech suggested that since my battery bank is so small and this charger is designed for a larger bank. Thanks for the link to the wiring website, it confirmed that I had that correct. With only 4 batteries I had the odds in my favor, lol.
  • VicVic Solar Expert Posts: 3,171 ✭✭✭✭
    Re: Repaired SW4024 settings?

    OK stmar, thanks for the info on the inverter model and added info for the event.

    It is lucky that you were able to get it repaired (I think).

    Yes, battery charging can be a long slog, and is very demanding of the hardware.
    Since you are GT/Backup configured, a lower charge current should not be a problem, if the grid is fairly reliable.

    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.
  • stmarstmar Solar Expert Posts: 369 ✭✭✭
    Re: Repaired SW4024 settings?

    "It is lucky that you were able to get it repaired (I think)."
    My thoughts exactly Vic, I got it done for less than half of what a new one would cost and did not have to do any mods to my system, plug and play, over 20% of that cost was shipping. The guy that repaired it found an AC transformer which was a stroke of luck to say the least since they are no longer made and very scarce. It seems to be functioning, had a power bump last night and did not know it until the grid came back up and a light flickered when it started syncing. Our grid is fairly reliable but we do have our issues with blizzards now and then so it is a comfort to have backup. Next step is to replace the battery bank. That is going to cost me my allowance plus some, lol. I may go with a dozen 6 volt Concordes to increase capacity, I have had good luck with the 4 12 volt ones I have now. I am still researching the pros and cons of
    6 volt vs 12.
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