MPPT60 150 Arcing

Nitro25Nitro25 Posts: 14Registered Users ✭✭
Hey Folks;
 
I just had a CC failure, and as luck would have it, I was right there to see and hear the Pop & Fire.
 
I’m asking your advice as to what you believe could have attributed to this.
 
As you can see “Q3” is toast, and “Q9” does not look so happy either. And should I change “Q1” also due to its proximity to “Q3”? (Heat?)
 
All wire connections were tight and dry.
 
Luckily I have a spare board from another CC biting the dust, so I can swap components.
 
The system is composed of two XW6048 inverters, three MPPT 60/150’s and 12,000 watts on the roof.
 
Sure would like to know why these Mosfets are blowing.
 


Update:
 
I replaced “Q3” and “Q9”, and put controller back on line. Turned on battery breaker, and CC booted normally and settled on “Low Light”. Turned on PV Breaker and CC momentarily flashed 56.2 Volts and 11 Amps, then you could hear the relay disengage and CC displayed “Low Light”. This would cycle twice and then display “Restart Pending”.
 
I shut down the CC and attempted a reboot, this time when I turned on the PV Breaker Arcing between the drain and source legs of the “Q3” mosfet returned.
 
Your Thoughts;
Nitro25





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Comments

  • mcgivormcgivor Posts: 2,205Solar Expert ✭✭✭✭✭
    How are the panels arranged, what are the specs of the panels?  Altitude and outdoor ambient temperature information would also be useful.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • mike95490mike95490 Posts: 7,902Solar Expert ✭✭✭✭
    Sounds like it's good and fried now .   Sorry.  Often there are some bias adjustments for high power MOSFETs
    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 ,

  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    > Mcgivor
    This cc is loaded by 16 REC235PE's, arranged in four strings. I'm here at sea level in Florida, Tampa area. Rooftop temps in summer approach 100* - 105* in full sun and still air. Never received any warnings from this CC, and the event log is empty.

  • mcgivormcgivor Posts: 2,205Solar Expert ✭✭✭✭✭
    edited August 22 #5
    Any chance of lightning when this occurred?  
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    Yes, ... Real Good Chance.
  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    What is causing the arcing now though? If the fet driver was dead, holding the fet open, is the Cap array building to such a voltage that its bridging the air gap between the drain and source leg? I have a scope, but I sure don't want to have my scope leads anywhere near a possible discharge like this one. Wish I had a schematic! 
  • VicVic Posts: 2,906Solar Expert ✭✭✭✭

    Nitro,

    In FL,  lightning is often a good guess for damaged electronics.

    Your RE235PE PVs appear to have the following specs:

    Max Power Voltage (Vmpp): 29.8 Volts
    Open Circuit Voltage (Voc): 37.4 Volts

    Strings of four PVs would have an STC (25 degrees C),  string Voc of 149 + V,   this is really too high for this CC.   High temperatures will reduce this voltage,  but in a cool morning,  this voltage could exceed the maximum rating for PV input voltage.   There is an input relay,  and probably some surge voltage protection on the PV in terminals that could help protect the CC from excessive Vin.

    Am not saying that this is not the result of a lightning event,   but in the future,  if you are running strings of four of those PVs you could have problems,   even in FL.

    On a 48V system,   strings of these 60-cell PVs is ideal,  on a 24V system,   strings of two would be fine ...   and,   so on.    FWIW,   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.
  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    Thanks much Vic,
    Yeah, I knew I was close, but Xantrex gave me their blessing.(Back before Schneider entered the picture.) But the problem at hand it trying to get this one on line. I noticed that the Fet (FDP2532) is rated right at 150V, what ever happened to margin? I guess I could look on Digikey for a beefier Fet. So, It's the shotgun approach where I order all new Diodes, Fets, and drivers, or try to trouble shoot the driver circuit with a scope. As far as getting a new CC ... I just found out what my Social Security was ... not in the near future!
  • Dave AngeliniDave Angelini Posts: 4,014Solar Expert ✭✭✭✭
    150v is max and if you come close to it, you are rolling the dice in your design, no matter what anyone tells you. 

    The mppt-60 logs and displays the max v in one of the user screens.

    I did not see any mention of SPD's on the arrays and the battery DC to the mppt's

    Replacement time and correct the system for reliability.

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

  • VicVic Posts: 2,906Solar Expert ✭✭✭✭
    Nitro25 said:
    Thanks much Vic,
    Yeah, I knew I was close, but Xantrex gave me their blessing.(Back before Schneider entered the picture.) But the problem at hand it trying to get this one on line. I noticed that the Fet (FDP2532) is rated right at 150V, what ever happened to margin? I guess I could look on Digikey for a beefier Fet. So, It's the shotgun approach where I order all new Diodes, Fets, and drivers, or try to trouble shoot the driver circuit with a scope. As far as getting a new CC ... I just found out what my Social Security was ... not in the near future!


    Hi Nitro,

    OK on the tight funds.   Even if the multiple-device failures were not caused by lightning,   the odds of replacing every obviously toasted part,   and having the CC come back up and run reliably seem small.

    If the event causing those failures was caused by lightning,   then,  IMO,  the odds of successfully getting this CC back up and running reliably seem much slimmer.

    Do you see sings of toasted MOVs (a surge protective device) on the PCB near the PV in terminals ?

    Assume that this is a Grid-Interactive system,    were there any issues with the inverters  --  any Faults?

    Anyway  wish you the very best of luck.      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.
  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    Hey Dave
    I read your Bio ... So you'll appreciate this.
    I was conceived on a Boat (56 double cabin Chris)(Too much info?) I was raised with Boats. I became a Marine Mechanic for about forty years. I was a licensed 100 ton Capt. And I went to work as a Marine field service rep for OMC out of Ft. Lauderdale.
    So I don't have to explain to you why not being able to repair something drives people like me Crazy!
    So ... until I'm totally defeated, I'm gonna keep trying.

    My PV's and Batteries are breakered to the MPPT60's through the Xantrex Distribution panel. I installed lightning arresters on each array feed, and in the main breaker panel, and I pay Duke Energy for their super duper lightning arrester piggybacked on my meter. And I hardwired all my pv frames to a 10' copper ground rod. I checked my log, and its blank, no events or history the surge may have wiped the firmware ... that's yet to be seen.

    So how close to 150v would you engineer yours?

    Thanks much Dave
  • mike95490mike95490 Posts: 7,902Solar Expert ✭✭✭✭
    something bridged 2 pins of Q3.  They are not supposed to neck down like that
     either a bug, or lightning, or a lightning bug

    But there was an arc there, that eroded the leads
    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 ,

  • Dave AngeliniDave Angelini Posts: 4,014Solar Expert ✭✭✭✭

    Captain,

     I would use the 600v charge controller mppt-80-600.  A no brainer with that much solar.

    Very hard for a bug to get in if it is properly installed.

    Did you have surge protection?

    Good Luck!

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

  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    Hey Vic;
    Nothing crispy near input lugs. When you really come down to it, the only obvious damage is that one Fet on the output bank, and the other Fet next to that 555 timer.
    No inverter faults, they're running fine on the remaining two CC's.
    So, I'm thinking that the fet driver is toast preventing two of the fets to be inop. The caps are still going to charge, and all that power has to go somewhere. So when they reach a high enough voltage they'll air gap across to ground on the source leg.
    So Shotgun it is, I'm going to replace the fets, fet drivers, fet timer, and the FR120n control fet, and probably the Schottkey diodes (Top Left) for good measure. Pennies on the dollar from Digikey.
    If it works ... Happy Man!

    Thanks Vic




  • mike95490mike95490 Posts: 7,902Solar Expert ✭✭✭✭
    replacing FET's without knowing why they failed, just spends your money at digikey.  
    Something melted the FET lead, and if it was Hi Voltage, pretty much assume 80% is fried
    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 ,

  • mcgivormcgivor Posts: 2,205Solar Expert ✭✭✭✭✭
    For a voltage episode to jump the gap between mosfet leads, it would have to be way in excess of the maximum rated voltage, consistent with an external surge, direct or induced, such as lightning, even with a SPD device installed. lightning has a way of defeating all protection, I've had my fair share to speak from experience. Taking the time to attempt a repair is applauding, not many venture down that path, best of luck.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    Hey mcgivor
    Thanks for the encouragement.
    After replacing the blown fet with a known good one, the arcing returned, that's the rub, but also a huge clue. Obviously, I have a voltage multiplier circuit in action here. (This is where a schematic is handy) Think of a Jacobs ladder charging and discharging. In order to see what's going on, I have to rig a bench test with a battery and a PV substitute, in order to have the circuit board uncased and accessible to probe with a DVM & oscilloscope. I need to back probe that fet gate circuit and see if that driver is telling it anything, just for my own satisfaction ... because my gut tells me it's deaf as a post. And if its not talking, why not. Is it a dead driver, or a circuit that supports the driver?
    This thing is just not that complicated, the problem we have is there aren't enough of us that have the experience, and the repair shops aren't sharing their occult knowledge.
    Parts are on the way, and if I figure this thing out, you guys will be the first to know.

    Thanks;
    Nitro25


  • BB.BB. Posts: 27,886Super Moderators, Administrators admin
    edited August 23 #19
    Generally, MPPT charge controllers use a buck mode switching power supply circuit (possibly with a synchronous rectifier)... So that will give you a starting point:

    https://en.wikipedia.org/wiki/Buck_converter

    Obviously cleaning of the circuit board and nearby components of any carbon traces/dust is important too. And in many cases the FET drive circuit(s) fail and cause the FETs to fail.

    And a failing FET can take out the drive circuit (and probably will).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Posts: 7,902Solar Expert ✭✭✭✭
    A big arc like that, will make a mess all over the circuit board, not just limited to the smokey looking parts
    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 ,

  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    Thanks Bill;

    So I guess we're on the same page. What's so aggravating is its a double board, and impossible to trace circuits. I fried a scope a while back, so I'm not real enthusiastic about putting my new scope in jeopardy.  But that's the only way to see whats happening.
    Any advice on how to set up a test bench configuration?
  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    "A big arc like that, will make a mess all over the circuit board, not just limited to the smokey looking parts"

    Yup! ... I know Mike, ... kinda like a BAD Marriage, it can screw up your whole board of life!
  • BB.BB. Posts: 27,886Super Moderators, Administrators admin
    You can use a (for example) 24 volt battery on the Vpanel and a 12 volt battery on the Vbatt... Or even use a bench top power supply for Vpanel and a 12 volt battery for Vbatt.

    Solar panels are voltage limited current sources... Although a good MPPT controller will accept a voltage source for Vpanel (MorningStar seems to support Battery input on Vpanel for some/many/all? of their MPPT controllers. Do not do this for PWM type charge controllers. Midnite suggested using a ballast resistor in Vpanel input for their MPPT controllers to make the voltage source less stiff.

    Vpanel you can start with a bench supply and current limit set way down (1 amp or so) or use a power resistor to limit to ~1-4 amps with a 10 volt drop (again with a 12 volt battery as load/source of boot power for MPPT controller).

    In general, always connect the battery bus first, and the Vpanel power second (in some cases, it is possible to damage the solar charge controller if Vpanel is powered before Vbatt... Note that Vbatt should be >~9.5 volts for most charge controllers).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • kc8adukc8adu Posts: 41Solar Expert ✭✭✭
    i would expect the voltage needed to jump that gap to destroy the mosfet.
    most go short s-d.
    energy that can open it will usually explode the case.
    maybe some snubber components are bad?
    need to see good pics of both sides.
  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    Yep kc8adu it arched from source to drain. Just talked to Schnieder, they don't offer board level advice. I'll get some better pics tomorrow.


  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    Better Pics, Board Wide.




  • mike95490mike95490 Posts: 7,902Solar Expert ✭✭✭✭
    he's dead Jim.
      with the SMT Ic's so close to the BBQ part, it's not likely they will be ok.  And the caps with the scored seam on top, can't tell if they have started to bulge or not, they don't look flat anymore
    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 ,

  • Dave AngeliniDave Angelini Posts: 4,014Solar Expert ✭✭✭✭
    What killed him Jim? 

     Lack of surge protection or water getting in? In an FA Schneider would power up the logged memory and verify that the 150V was not exceeded. It looks to me that water got in.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    Ok ... made progress, there's no arching. Replaced Q1, Q3, Mosfet driver for those two, and Mosfet Q9. Tested unit with bench power supply acting as PV circuit, and 12v battery as per "BB's" post Aug 27th. everything seemed to function ok. Installed in the system and brought it online with controller (Battery) breaker, unit booted up just fine and settled on "Low Light". I energized the PV breaker and could hear relay engage and momentarily saw system status readings, then the relay kicked out and "Low Light" reappeared. Approximately ten seconds later relay engaged again, system stats showed up again, and then relay disengaged and "Restart Pending" appeared and remained, controller never restarted. All pages function, settings, meters, history, etc, and are accessible even though controller is awaiting restart. Voltage on battery buss is steady 56.2 volts, and voltage on PV Buss is steady at 120 volts. So, what is telling the logic that there's "Low Light"? Could it be as simple as a bad relay kicking out?

    Dwight
     

     








  • Nitro25Nitro25 Posts: 14Registered Users ✭✭
    New wrinkle ... The CC is now throwing a "F71" fault code (DC over current)
  • Dave AngeliniDave Angelini Posts: 4,014Solar Expert ✭✭✭✭
    Are you a baseball fan of the SF Giants?  We call this Torture!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

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