SW4024 DC Over Voltage fault?

stmarstmar Solar Expert Posts: 323 ✭✭✭

I am getting a DC Over Voltage fault on my system. I have my over voltage setting at 30 volts. I don't think it is from the solar array since it goes into PWM regulation at just over 28 volts and I have never seen my Morningstar PS30 anywhere near 30 volts. Could it be the Conext charger? Where can I find the cause? It does not seem to effect the system performance, I discovered it from an email alert and when I checked the log I saw that it has happened multiple times.

Comments

  • EstragonEstragon Registered Users Posts: 3,621 ✭✭✭✭✭

    Is this high voltage pv input, or battery voltage?

    PV voltage is usually highest first thing on cold winter mornings, and sometimes on breezy/broken cloudy days. It drops off as the sun warms the panels. Not generally a problem, but you may want to set a bit higher.

    Battery charging voltage will also be higher if bank is colder and the RTS is used.

    Depending on battery type, temperature adjusted charging voltage may well be over 30v on a cold 24v nominal. Having a HV disconnect set too low may prevent the bank from getting a proper absorb.

    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,449 ✭✭✭✭✭

    Raise the setting above what you have. I can't remember but it will generate warnings, then faults lower than what is programmed for a good reason.

    You should not set it lower than the default also unless you have a very specific reason. Smaller battery banks often do this. The fault is not going to cause a problem with charging.

    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • mike95490mike95490 Solar Expert Posts: 8,253 ✭✭✭✭✭

    Are you getting FAULT or WARNING ?

    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: 323 ✭✭✭

    2019/02/21 16:52:4849 DC Over Voltage

    2019/02/21 16:52:4049 DC Over Voltage

    2018/12/28 17:15:3449 DC Over Voltage

    These are a sample and they are Faults, I have had no Warnings logged. It has to be battery voltage because the system does not recognize the PV input since the PS30 controller does not talk to the system. Another reason to get the Xanbus controller. This is intermittent so it may be environmental, cold sunny days as you suggested. What voltage should I set it to? 30 is the current and default setting.

  • BB.BB. Super Moderators, Administrators Posts: 29,054 admin

    Fault voltages are "it depends".

    For example, as I recall, the hard fault voltage for an XW (Schneider/Xantrex) hybrid inverter-charger is 72 Volts for 48 volt bank (or 36 volts for a 24 volt bank).

    For battery charging, ~29.5 volts at 75F is a normal absorb voltage for an FLA battery (Flooded Cell Lead Acid). Get near freezing:

    • -0.005 mV per cell per C * (0C battery - 25C std) * 12 cells (24v system) = +1.5 volts for "freezing" temperature battery bank offset
    • 29.5 absorb + 1.5 volts off set (0C battery) = 31.0 volts nominal Absorb @ 0C

    For Battery equalizing, you are looking at 30-32 volts...

    For Inverters, they tend to run from 30-32 volts high voltage cutoff. You have to check the manual to see what their shutdown point is (or should be).

    At this point, 30 volts is too low for high voltage fault. I would suggest a "warning" at 32 volts, and a hard fault at 36 volts (unless the inverter has a different requirement).

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 29,054 admin

    I should add, a Fault or Hard Fault, shuts down the system (hopefully any charging sources too). And a Hard Fault would normally require operator intervention to reset.

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • stmarstmar Solar Expert Posts: 323 ✭✭✭

    There was no system shutdown, I just received an email that said there was a Fault so I checked the Historical Log and saw several other dates there was a DC Fault, no email for those dates and it was intermittent. 30 volts is the DC over voltage default for the SW4024. I will leave it on AC Support mode and see if I get a fault. The Fault was reset automatically and did not show up as an Active Fault just on the Historical Log. Since I have Lifeline AGMs they are probably able to take a higher voltage than the 30 volts default. If the AC Support mode does not work I will increase the over voltage setting. My batteries are in a fairly cool place, below 60 F most of the time so this may also allow the voltage to creep higher with the BTS. Thanks for the info.

  • Dave AngeliniDave Angelini Solar Expert Posts: 4,449 ✭✭✭✭✭

    Hey Bill, hope your winter was better than mine. Snow impacted for a month. I heard the other side of the Sierra has 500 inches.

    For the OP a hard fault will not shut down his CC because it is not in the xanbus network. Yet another reason to stay with one brand.

    I am surprised that the default is so low. Normally it would be set above the EQ setting or 31V on a 24V nominal. Since we have no idea what battery he has the guidance is going to be just set it higher like 32v. A 24v inverter is going to have these issues with less than 400AH of battery. Some of this is also fixed by using a "custom battery" choice in the charge menu on the CSW I seem to remember.

    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • MrM1MrM1 Registered Users Posts: 404 ✭✭✭
    edited February 22 #10

    For an F49 DC over voltage fault code according to the manual (p5-8)you would ...

    Cause: Voltage at the DC input terminals is above the High Battery Cut Out Setting

    Solution: Clear the fault and attempt restart. Ensure battery voltage is 21–33 VDC (default settings) at Conext SW terminals. Check all other charging source outputs, battery cables.

    My question is, if this is a 24v system, why do you have the High Battery Cut Out set to 30vdc?  I am probably not understanding your issue completely. But Charging even with the SW can be done at 32vdc for EQ.  I have my High Battery Cut Off set at 33 VDC. 

    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • PhotowhitPhotowhit Solar Expert Posts: 4,880 ✭✭✭✭

    stmar said; "...30 volts is the DC over voltage default for the SW4024."

    Schneider says; High voltage Shut down cutoff 33.0 volts(default) (other values selectable)

    I suspect you have set a warning.

    Gosh I'm tired of trying to deal with new crappy software! Guess I'll read the changes, again and be frustrated AGAIN, until I just give up!

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • PhotowhitPhotowhit Solar Expert Posts: 4,880 ✭✭✭✭
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • stmarstmar Solar Expert Posts: 323 ✭✭✭

    You were correct, the High Voltage Cutout default is 33 volts. I must have changed it to 30 somewhere along the line, will have to go through my notes because I do not recall changing it. Thanks for all the input.

    I am going to leave it on AC Support for a while and see what the difference in power usage is. I was gone for a few weeks and had that feature off, acting as a UPS, so I should have a good comparison.

    New charge controller may be needed. My system is SW4024 120/240 inverter, SCP and Combox, 400ah battery bank (4 X 6 volt AGM Lifelines), solar array (don't have the specs). Will the XW MPPT 60 work with this system or is it overkill? Will it be a plug and play with the Xanbus feature? Don't want to spend over $500 and then have to revamp the system for it to fit.

  • MrM1MrM1 Registered Users Posts: 404 ✭✭✭

    What CC do you have now?

    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • stmarstmar Solar Expert Posts: 323 ✭✭✭

    Why would the Historical Log under Events not have any Warnings but has Faults listed? Just curious.

    Controller is a Morningstar PS30 PWM.

  • stmarstmar Solar Expert Posts: 323 ✭✭✭

    No faults since I put the correct value in the Over Voltage field, still don't know how that happened. If I were to go with the XW MPPT 60 would I have to wire for 60 amps? Right now I have #8 wire going to my 30 amp controller. It will be a while because of the weather but I want to know what I am getting into. Any other tips appreciated.

  • EstragonEstragon Registered Users Posts: 3,621 ✭✭✭✭✭

    As long as you have the 8ga wire protected with appropriate size OCD (fuse or preferably breaker), and the array won't put enough to trip the OCD, you can likely stay with it. Going to mppt, you may want to rewire the array for higher voltage / lower current, which allows use of smaller input wire for given pv wattage.

    If you need to add OCD though, might want to size the wire for whatever current you might eventually need.

    I'm assuming the 8ga is CC input. If it's output to bank, I'd upsize it to whatever size the new controller will physically handle.

    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • BB.BB. Super Moderators, Administrators Posts: 29,054 admin

    Is this from Array to Charge controller (panel ratings, number of panels, series/parallel connections, distance from array to charge controller)?

    Is this from the charge controller to the battery bank (distance from charge controller to battery bank)?

    Nominally, I would start with maximum continuous current you expect... Say 60 Amps.

    Then multiply by 1.25 (NEC derating for continuous current flow--hours at a time):

    • 60 amps * 1.25 = 75 amps round up to 80 amps for Breaker/fuse/wire capacity

    I like to use the NEC wiring table (vs marine), it is much more conservative (and takes into account wiring insulation, ambient temperature, etc.). This is a simplified NEC table:

    Suggested wire would be 4-3(or 2) AWG. Note, check controller design. Many cannot take this large of cabling.

    Then you want to look at voltage drop. If these was from the array to the charge controller, you would want around 1% to 3% maximum drop typically.

    For Charge controller to battery bank, you want around 0.05 to 0.10 max voltage drop for a 12 volt bank (~0.1-0.2 max for 24; and 0.2-0.4max drop for 48 VDC bank).

    Say 24 volt bank, and 5 feet from controller to battery bank, 60 amps, and 0.1-0.2 max drop. Play with the AWG size and get:

    https://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=0.8152&voltage=24&phase=dc&noofconductor=1&distance=5&distanceunit=feet&amperes=60&x=0&y=0

    4 AWG gives:

    Voltage drop: 0.15

    Voltage drop percentage: 0.62%

    Voltage at the end: 23.85

    Which is not bad...

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • stmarstmar Solar Expert Posts: 323 ✭✭✭

    If I change out the controller I will have to upgrade the wiring. Cabling from the array is large enough so it will be just the inside wiring which is no big deal.

Sign In or Register to comment.