Which limits can I push?

PhilSPhilS Solar Expert Posts: 370 ✭✭✭
Just before Memorial Day we had a local "wind event" (made the local news for a few days but NOTHING like the poor souls in the Midwest). I had one solar panel take a projectile from the rear (and out of more than two dozen panels we were VERY lucky!).

This is a Mitsubishi MF170EB3. I had six, wired in two strings of three into an Outback FM60 feeding a 12V bank. I acknowledge that the 1020 watts slightly exceeded the recommended supply for the FM60 but in those rare cases of perfect peak power, the controller just limited the output to about 60A.

Now I have five of these panels left. There's sufficient capacity with the rest of my array and we will not be replacing the damaged panel.

I rewired four panels in series to feed the FM60 (gotta love MC connectors at times like this!). The panel Voc is 30.6 so the total 122.4 is well within the FM's limit of 150.

What should I do with the fifth panel?

I'm tempted to wire all five in series but the total Voc would be 153. I'm used to military "safety factors" and think it could be just fine. Or not? I'd hate to fry the FM, but could 3 volts over really be too much?

I can't use it on my RV since it's a 24V panel, and the other two RV panels are 12V feeding a C35 controller. In fact, I can't add it to any of my other banks for that 24V reason. It's a waste to put the panel in the garage.

Can I get some opinions and/or suggestions please?

Phil

2454321750043562119S425x425Q85.jpg

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Which limits can I push?

    Time to think up a new project! :D

    Your 122 Volts is pushing it. If the weather ever gets seriously cold where you are the Voc could exceed 130. I'm not sure exactly what the FM60's limits are, but the venerable MX60 would actually shut down over 130. Over 150 and you've got problems.

    Of course you could buy a Midnight Classic 150 or 200 - problem solved!

    You are just looking for an excuse to spend money on a new toy, right? :p

    But don't go all panels in one string: over 150 it will shut off and won't restart on its own. You have to disconnect and reboot. Been there, done that, cursed the -40C Winter and my "72 Volt" array.
  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: Which limits can I push?

    Thanks, Coot.

    That's the info I needed. The limit for Voc on the FM60 is 150 but from what you say, if it hit that limit it'd shut down until I manually reset it. I don't need to be doing that, even infrequently. Of course, it doesn't get nearly as cold here as there... temps got down to 28F a couple of times last winter.

    It seems the 4 in series won't be a problem but I guess I'll rule out putting the 5th panel in this string.

    Maybe someone here can give me some repair tricks for that 6th panel?

    Phil
  • ggunnggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: Which limits can I push?
    PhilS wrote: »
    Maybe someone here can give me some repair tricks for that 6th panel?
    Looking at the picture you posted I would say that replacement is your only option.
  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: Which limits can I push?
    ggunn wrote: »
    Looking at the picture you posted I would say that replacement is your only option.

    Yep, no doubt about THAT! I snipped off the MC cords thinking that was about the only "valuable" part left. I could pry off the aluminum frame but for what I'd get, I don't think even that is worth the effort.

    It's in my junkpile now. SOOOO glad it's the only part with damage that matters. Bolts got pulled out of Uniracs but you can slide bolts into them from either end even if there's a big 'wow' in the middle where a bolt pulled through (stainless is sure stronger than aluminum).

    It was a mess but could've been very bad. I lost over 4 dozen big trees but the ones that were twisted off near the house not only missed it, but the garages and the RV and the cars too. All were missed by less than a yard but a miss is as good as a mile.

    I need to get an old 36" Stihl 054 into the shop because my 16" Husky isn't big enough for much of this cleanup. I haven't used that Stihl for decades ... it's too big and heavy for my normal forest maintenance. Lotsa big pines down, too bad they don't make good firewood.

    Phil
  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: Which limits can I push?
    Time to think up a new project! :D

    Your 122 Volts is pushing it. If the weather ever gets seriously cold where you are the Voc could exceed 130. I'm not sure exactly what the FM60's limits are, but the venerable MX60 would actually shut down over 130. Over 150 and you've got problems.

    But don't go all panels in one string: over 150 it will shut off and won't restart on its own. You have to disconnect and reboot. Been there, done that, cursed the -40C Winter and my "72 Volt" array.

    I've been reflecting on your experience Coot.

    IF I add the 5th panel to the string, the worst that could happen would be the FM shutting down and needing a manual reset. I really didn't expect that the FM would "fry" but did not know what WOULD happen if Voc got over 150.

    I'm getting tempted to give it a try unless I see some other compelling reason not to. I'd be a little less inclined to try this if I weren't dealing with MC connectors. To change from 4 in series to 5, or back again would take less than 30 seconds.

    I've got the panel input fused and a breaker on the output, so a manual "reboot" actually shouldn't be that difficult anyway. And if I returned home on a cold day to find the FM shut off, I'd know the cause.

    What does an Outback controller indicate when that happens? Blank display? Something in the display that says it's "off"?

    Phil
  • boBboB Solar Expert Posts: 995 ✭✭✭✭
    Re: Which limits can I push?
    PhilS wrote: »
    I've been reflecting on your experience Coot.

    IF I add the 5th panel to the string, the worst that could happen would be the FM shutting down and needing a manual reset. I really didn't expect that the FM would "fry" but did not know what WOULD happen if Voc got over 150.

    I'm getting tempted to give it a try unless I see some other compelling reason not to. I'd be a little less inclined to try this if I weren't dealing with MC connectors. To change from 4 in series to 5, or back again would take less than 30 seconds.

    I've got the panel input fused and a breaker on the output, so a manual "reboot" actually shouldn't be that difficult anyway. And if I returned home on a cold day to find the FM shut off, I'd know the cause.

    What does an Outback controller indicate when that happens? Blank display? Something in the display that says it's "off"?

    Phil

    The extremely old MX60s would shut off at anything over 130 Volts but not too long after that, it was like 141 Volts and then 146 Volts I think. The FM series is something like 146 Volts now I believe.

    The old MX60 display would flash flash flash when it got to over 150 Volts input but I don't know that happens nowadays. I don't know why an FM would STAY off though ? Should just got to sleep and then re-wake up when the PV V input drops below the turnoff voltage.

    boB
  • BB.BB. Super Moderators, Administrators Posts: 32,023 admin
    Re: Which limits can I push?

    Older Outback (and probably other brands) will log >150 VDC and "poof" there goes your warranty. I would assume the newer models will also log high voltage events.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Which limits can I push?

    Besides which it won't work at all: your panel Voc is 30.6. Multiplied by 5 is 153, which is instant shutdown. Since panels hit Voc the moment light hits them it will just shut down before producing any power. Unless they've changed the FM a lot since the MX.

    My MX60 (and you have to understand there are many years of these beasts with various firmware) would stop at 130 Volts but reset. With 150 it shut off with the flashing display like boB said, and require being disconnected from the batteries and then reconnected to reboot.

    Still worked though; didn't fry. Outback equipment, for all its cantankerous "out-of-date" design, is tough as tanks! :D
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Which limits can I push?
    PhilS wrote: »
    Lotsa big pines down, too bad they don't make good firewood.

    Actually it makes great campfire wood - lights easy and burns great. You can even mix a piece or two in with hardwood if you have a wood stove or fireplace, just don't use more than that and don't do it all the time.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Which limits can I push?

    Up here the lodgepole pine makes great firewood. Which is good since we have hundreds of thousand of hectares of dead trees thanks to the beetles. :cry:

    Our softwood grows slower; it's denser than the more southerly trees.
  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: Which limits can I push?
    BB. wrote: »
    Older Outback (and probably other brands) will log >150 VDC and "poof" there goes your warranty. I would assume the newer models will also log high voltage events.

    -Bill

    OK, VERY good point Bill. Especially since I got the 5 year warranty included with this FM60 and I'm guessing I've had it 3 years so far.

    I only added the 4th panel in the series last night and won't even see how that configuration is performing until later today.

    Here's a link to what caused the problem:

    http://www.youtube.com/watch?v=a1DcjFgciYY

    We watched it live on TV while we watched it live out the window. We look out over Durham which is about 10 miles west. A friend farther up the hill got a photo of the remnants of the vortex directly over our house. The newscasters kept saying it'd die off once it started into the foothills, and we are about 700' above the valley floor so we figured we'd be safe. And we were, getting hit by the thing after it had started to disapate otherwise there might have been no new posts from me again.

    It was depressing to see 26 solar panels piled up in the yard but refreshing to see only one broken.

    We got hit by a tornado in South Carolina and I've always commented that I'd rather get hit by an earthquake than another tornado (California native, I've probably been through dozens of earthquakes). "California doesn't get tornados."

    Phil
  • solarvicsolarvic Solar Expert Posts: 1,060 ✭✭✭✭
    Re: Which limits can I push?

    Was wondering why you don,t get your insurance co to replace your whole array if you can,t find the panels needed to replace the damaged ones. :Dsolarvic:D
  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: Which limits can I push?
    solarvic wrote: »
    Was wondering why you don,t get your insurance co to replace your whole array if you can,t find the panels needed to replace the damaged ones. :Dsolarvic:D

    Reason 1: I can replace the damaged panel for less than $600 and I have a deductible of $1000. I haven't found an identical panel but I've found one within an inch of the dimensions that would work.

    Reason 2: I was actually over the recommended total input wattage with that array so replacing that panel would put me back "over" the limit. Four panels is under the limit. Five panels would be perfect but the only way I can use five is as described, all in series. I still haven't decided whether to hook up the fifth panel yet since I don't yet have the entire array re-mounted. We were generating power the next morning after turning all the panels face up on the ground. My batteries have been getting full and I have almost half of my array mounted again but won't finish for a few weeks (been out of town and leaving again soon).

    Reason 3: I wouldn't allow ANYBODY else to work on my system. I learned decades ago that I could allow somebody else to do work for me (auto, home, other things) and then I could re-do the work to my satisfaction. Easier just to do it myself the first time.

    I've been giving the situation much thought. We had planned on leaving on a trip the next morning but had to delay our departure until I could cut and drag away enough of the downed trees to get the truck out of the garage and hooked to the RV. My schedule has given me more time to think and plan than to actually do the work, but since the batteries are getting full every day, our housesitters haven't been without power.

    Phil
  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: Which limits can I push?
    boB wrote: »
    The extremely old MX60s would shut off at anything over 130 Volts but not too long after that, it was like 141 Volts and then 146 Volts I think. The FM series is something like 146 Volts now I believe.

    The old MX60 display would flash flash flash when it got to over 150 Volts input but I don't know that happens nowadays. I don't know why an FM would STAY off though ? Should just got to sleep and then re-wake up when the PV V input drops below the turnoff voltage.

    boB

    Thanks, boB, I missed your post yesterday. On the side of the FM it says max Voc is 150 (vs 130 for the two MX's I have).

    Once I get all the arrays back in the air, I'll probably try the fifth panel in series. If it becomes a regular occurance (shutting down) it'll be easy to change back to four.

    IF my batteries are all "full" and the controllers are putting in zero amps, would the voltage in rise to an open circuit reading?

    Phil
  • VicVic Solar Expert Posts: 3,113 ✭✭✭✭
    Re: Which limits can I push?

    Hi PhilS,

    Sorry to hear of the loss of that one panel, but seems that you were very lucky!
    Happened to be watching KCRA TV at that period, (am sure that was the source of the CNN video). Dramatic.

    But, boy with a Vmp of 122 V, (think that you must be on a 12 V system) ... your Voc may be a problem. BUT, to me, the Vmp is also a problem. In Float, under light loads, the Vin could l rise to about 135 or even 140 V, at least, extrapolating from my system -- with light loads when in Float. My systems use MX-60s, and run Vmp of 106 V.

    Perahps the FM is quite different than the MX, but more likely, they are fairly similar. My MXs run hot, delivering a few amps to the battery when in Float, with Vin at about 120-122 V. Even at these low power out levels, the internal fan would cycle. Running A/C in the power room solved this (lower temp AND lower Vin). It is also possible that your system runs much more load in Float (and Asorb), so, this would limit Vin ... and so on.

    But, over a period of time, the FM might become disappointed in this.

    My max recorded Voc is now 140 on one MX, and 141 on the other. The record low temps here are a bit lower than what you noted. Have felt that I was PUSHING it, but you would be a record-holder IMHO with this configuration!

    Whatta I know ?! But if you could find a near-fit on a replacement panel, I'd bet the system would be happier. with your customary Vmp. Continued Good 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.
  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: Which limits can I push?
    Vic wrote: »
    Hi PhilS,

    Sorry to hear of the loss of that one panel, but seems that you were very lucky!
    Happened to be watching KCRA TV at that period, (am sure that was the source of the CNN video). Dramatic.

    But, boy with a Vmp of 122 V, (think that you must be on a 12 V system) ... your Voc may be a problem. BUT, to me, the Vmp is also a problem. In Float, under light loads, the Vin could l rise to about 135 or even 140 V, at least, extrapolating from my system -- with light loads when in Float. My systems use MX-60s, and run Vmp of 106 V.

    Perahps the FM is quite different than the MX, but more likely, they are fairly similar. My MXs run hot, delivering a few amps to the battery when in Float, with Vin at about 120-122 V. Even at these low power out levels, the internal fan would cycle. Running A/C in the power room solved this (lower temp AND lower Vin). It is also possible that your system runs much more load in Float (and Asorb), so, this would limit Vin ... and so on.

    But, over a period of time, the FM might become disappointed in this.

    My max recorded Voc is now 140 on one MX, and 141 on the other. The record low temps here are a bit lower than what you noted. Have felt that I was PUSHING it, but you would be a record-holder IMHO with this configuration!

    Whatta I know ?! But if you could find a near-fit on a replacement panel, I'd bet the system would be happier. with your customary Vmp. Continued Good Luck, Vic

    Yes, it was the KCRA helicoptor. As we were watching it on TV and out the window, we were actually looking for the helicoptor. Please limit the comments regarding the wisdom of our standing in a mobilehome, watching a tornado coming directly at us, and looking for the helicoptor :blush: I already feel foolish enough.

    IF we had headed for the nearest ditch deep enough to get in, we'd have gotten hurt, at the least. A tree came down in that exact spot. And the newscasters kept saying "... it'll die down as soon as it hits the foothills..." so we only became concerned when it started getting crazy, and we backed away from the windows. Too late then to do anything else. Wish we'd moved windows tho, so I could have seen flying solar panels, tethered only by my tightly bundled wiring loom.

    I looked closer at my CCs last night. The FM60 says max Voc is 150. The older MX60 says 120. The newer MX60 says 150. I wonder if the label was the only change or if there was a hardware change that allowed the bigger rating.

    These panels are still on the ground and get shaded late in the afternoon by the panels now back up. Meaning, I'm not able to see any readings when the sun is directly on the panels until a weekend that I'm home. But I have seen an input voltage of 100. Since that's 4 panels, it'd have to be 125V with the fifth panel. I'm guessing it would be more if in the sun.

    SOOOO... as I waver back and forth on this decision, I think I'll leave it with 4 panels in the string for the foreseeable future. The FM cooling fan has always run a lot, since there were 1020 watts to a 12V bank. This will be easier on the unit and if I'm still filling the batteries, that might be the better choice to extend the life of the FM60.

    I thank everybody for the opinions about this fifth panel and believe "conservative" will be the answer.

    Phil
  • solarvicsolarvic Solar Expert Posts: 1,060 ✭✭✭✭
    Re: Which limits can I push?

    Phils, What kind of panel did you think you could replace the damaged one. I also Have 2 mitsubushi 175 watt panels and 8 shuco 180 watt panels whick someone said mitsubishi made. If you cover up the labels you can,t distinguish any difference visually. Wish I could find a couple more of them. I think you aren,t suposed to sell too much on here as it might take sales away from our forum host. Its a big problem to replace a broken panel or add a couple more after they are out of production. It would be nice if we can post wanted to buy on here for out of production panels. Someone might have too many and some might not have enough. :Dsolarvic:D
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Which limits can I push?

    Occasional sales/wanted postings for forum members is okay, just keep the discussion PM after an initial posting.
    Something like:

    I've got an Alpha Power 600 Watt 36 VDC inverter with sun transformer if anyone's interested, PM me.

    Of course if it starts to look like Craigslist around here you can bet the policy will be "revisited".

    What we really object to is links to direct NAWS competitors. :grr
  • BB.BB. Super Moderators, Administrators Posts: 32,023 admin
    Re: Which limits can I push?

    Like Marc said... Personal solar RE sales are perfectly OK.

    Regarding links to competitors--We are not that hard on folks. Mostly, links (to anywhere that is "work safe/family friendly" that answer questions are fine.

    What we don't want to get into is "...hey there is a sale at XWY.com at $0.92 per Watt for Brand solar panels...".

    If anything gets out of hand, usually friendly reminder via a PM is all we do.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: Which limits can I push?
    solarvic wrote: »
    Phils, What kind of panel did you think you could replace the damaged one. I also Have 2 mitsubushi 175 watt panels and 8 shuco 180 watt panels whick someone said mitsubishi made. If you cover up the labels you can,t distinguish any difference visually. Wish I could find a couple more of them. I think you aren,t suposed to sell too much on here as it might take sales away from our forum host. Its a big problem to replace a broken panel or add a couple more after they are out of production. It would be nice if we can post wanted to buy on here for out of production panels. Someone might have too many and some might not have enough. :Dsolarvic:D

    I just did some preliminary searching simply to see IF I would be able to replace the panel. I found a couple that could work but didn't go any farther in that direction since I really didn't plan on getting a replacement. I was just exploring options.

    Of course, the resulting answers of this thread leave me with the one extra panel. I'll likely mount it but not wire it. It'll be ready tho, in case Coot finds himself with an extra Midnight Classic 200 he doesn't know what to do with.

    The only weekend I've had free since the storm was spent with a chainsaw. Maybe I'll get more panels mounted at the end of this week, since the saw work will be ongoing for a long time.


    Phil
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,034 ✭✭✭✭✭
    Re: Which limits can I push?

    Phil,

    Are the cooling btu's getting a workout this week?

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

  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: Which limits can I push?
    Phil,

    Are the cooling btu's getting a workout this week?

    --Dave

    They sure provided some needed relief the past couple of days Dave. S'posed to be cooler this weekend... low 90's vs the low 100's.

    We ran the generator last night so we could put that Sanyo at max power without draining the batteries. Not different than previous times where we needed to run it in order to power two swamp coolers without draining batteries, but WAY different in the quality of dry cool air conditioning!

    Phil
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,034 ✭✭✭✭✭
    Re: Which limits can I push?

    Nice ! Ours shut down last night with the sun at 7:55pm. Either way they are a gamechanger!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: Which limits can I push?
    Nice ! Ours shut down last night with the sun at 7:55pm. Either way they are a gamechanger!

    Yeah, last night was the first time we took a bite of bullet and ran the genset. Every other day we have just been leaving it on "low" all day and by 7 or 8 pm it's up to 79 or 80 inside, with the outside temps above 100.

    80 is still better than the 100 it'd be inside without the Sanyo, but after running on low all day then switching to max power about 6, by 8 it was almost getting TOO cool (almost, not quite!).

    S'posed to be cooler for the next week or so, shouldn't be using the gen for awhile now.

    Phil
Sign In or Register to comment.