HELP! Solar Array not working.

terrapinflyer
terrapinflyer Registered Users Posts: 8 ✭
in Off Grid Solar & Battery Systems #1
I could REALLY use some help here.

First off- I have lived off-grid (solar and or hydro), off and on, for probably 2/3rds of the past 25 years. I am NOT an electrician, but have had to become fairly competent.

So- I recently installed 3 seperate solar arrays on my farm. Used Kyocera 125w 12 v panels w/ MC2 connectors. All tested at time of take down (not by me but by someone trusted). Two of the arrays work perfectly. One is NOT working at all.

system: 5 of the above mentioned panels. Approz 20' run through 2" conduit to Homeline QO Line breaker box. Each panel on 15A QO fuse. Xantrex/Trace/Schneider C60 charge control. Positive out to Blue Sea Systems breaker, then to Batt +.

I should maybe mention- this system as well as one of the others is actually two systems combined- ie: one is 10 panels, the other 8, which are split between two breaker boxes and charge controls.

So- possible mistakes- when I installed this I did not fully test it- I didn't have the tools with me. But I did, and still do, read ~19 V from the panels, so I assumed they were working. For a couple weeks the system was keeping up- mostly (or wholly) due to to 35A portion tied in. I had a suspicion that one or more of the grounds from the panels that had been spliced (10 AWG THNN) may have come apart when pulled through the conduit. But when removed this does not appear to have been the case- they were well spliced and taped, and the wire run was taped to prevent stress on the splices when pulling.

In the meantime someone else wired up some DC fans- and in the process left the main battery ground loose. It was several days or longer before I caught that.

When I Initially wired up the system, I forgot to tie together the two positive bars in the breaker box. So three of the panels were truly connected. two were tied into the breaker box with their negatives tied into the battery negative, but the positives not tied into the battery or charge controller (they did not trip the breakers).

Oh- and a final note- once I put a Trace digital display on the charge controller- it read roughly 12 watts coming in. About a tenth of 1 panel.... I only had time to test 3 of the 5 panels today- but so no juice coming in at all.

So here I am- tired and very confused. I cant imagine that out of a batch of 22 panels that the 5 that were defective would magically end up on the same array. And maybe I'm missing something simple here but I don't see what would have killed them.

But maybe that's it- there's something simple I'm failing to grasp that fried them?

H....E...L.....P
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #2
    Re: HELP! Solar Array not working.

    Please draw the system out, and post as an attachment... your description is a bit confusing, then there may be some comments to make other than check each panels Voltage input to the combiner box.. and after the CB and going into the CC.

    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #3
    Re: HELP! Solar Array not working.
    terrapinflyer wrote: »
    system: 5 of the above mentioned panels. Approz 20' run through 2" conduit to Homeline QO Line breaker box. Each panel on 15A QO fuse. Xantrex/Trace/Schneider C60 charge control. Positive out to Blue Sea Systems breaker, then to Batt +.

    ...
    But I did, and still do, read ~19 V from the panels, so I assumed they were working.
    So here I am- tired and very confused. I cant imagine that out of a batch of 22 panels that the 5 that were defective would magically end up on the same array. And maybe I'm missing something simple here but I don't see what would have killed them.

    But maybe that's it- there's something simple I'm failing to grasp that fried them?

    H....E...L.....P

    It is very hard to fry a solar panel with just battery voltage and their own power. If your per-string fuses are no higher than the maximum series fuse specified for the panels they should be fine.
    Step 0: What is the battery voltage? If the batteries are fully charged the CC will not be trying to pull much current from the panels. If the batteries are not fully charged, then it may be the CC that is bad not the panels.
    Step 1: remove all fuses or otherwise disconnect the panels from each other at the + end.
    2. Measure voltage on each. This should be around the 18-19 volts you measured. Or higher. When under load that voltage will go down.
    3. Carefully using an ohmmeter (i think he meant dvm reading amps, niel) and a switch determine the short circuit current from each panel. They should be similar and close to the specified Isc if the panels are in full sun.
    4. If the CC is good and the panels are producing current and the batteries need charge, the problem has to be in the wiring from fuse box to CC or CC to battery.
    SMA SB 3000, old BP panels.
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  • terrapinflyer
    terrapinflyer Registered Users Posts: 8 ✭
    #4
    Re: HELP! Solar Array not working.

    Hi,

    Will do- but it will be a couple days before I have access to a scanner.

    So simply put:
    Problem system:
    5 kyocera 125W panels. NOT combined at the banels- individual +/- run to Homeline QO breaker box. Each panel + to individual 15A breaker. All negatives to common neg bus.

    Two positive rails in breaker box combined, run to PV Load of Trace 60A charge control. Neg out to common neg in control. Other common neg from control direct to battery neg. Battery + connection on charge control runs to a Blue Sea Systems 60A fuse/breaker, from there to Battery Positive.

    Other system tied into this battery bank is 3 of the same panels with a 35A Trace charge control. Works fine. (As does the two panels I wired in to the "bad" system when I removed the 5 today).

    Battery bank is 6 6V interstate deep cycle batteries wired for 12V.


    Since you mention checking the panels voltage- one I was only getting 15V+ but the others 19V +/-. So I'm confused why I am getting no amps/watts in... I thought if I was reading proper voltage then the panels were indeed working?
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #5
    Re: HELP! Solar Array not working.
    terrapinflyer wrote: »
    Two positive rails in breaker box combined, run to PV Load of Trace 60A charge control.
    Sounds good. Just to double check, are you sure you have the Trace jumpered for Charge Control rather than Diversion Load?
    SMA SB 3000, old BP panels.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #6
    Re: HELP! Solar Array not working.

    first of all i do hope by your saying combined systems that the only thing in common is the batteries for combining all pv inputs to 2 or more controllers will not work.

    2ndly unless you have an mppt controller i do trust all pvs are paralleled as pwm controllers do not downconvert.

    3rdly what is the meaning of this, "Neg out to common neg in control."
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  • terrapinflyer
    terrapinflyer Registered Users Posts: 8 ✭
    #7
    Re: HELP! Solar Array not working.

    @ Inetdog:
    Battery voltage today was high 11 to about 12.2 depending on the time.

    step 3- the ohmeter. I won't have a chance for this until monday. (which will give me time to refresh my memory…multimeters and electrical laws are not 2nd nature to me.

    the problem is defintely not #4 - I grabbed a working charge controller off one of the other arrays (after tripping the breakers) and did a double test with that. I also started bypassing the breaker box completely and ran each panel into the charge control directly… (only tested 3 of 5 but none were putting in watts/amps, while when testing using two of my extra panels laying around both worked fine). And at one point I decided to bypass the Blue Sea Circuit breaker inline between the charge control and the battery + by running straight from the battery + to the Battery + on the charge control.(it wasn't tripping- just checking it wasn't defective) but it made no difference.

    And yes- I checked, double checked, and triple checked all the jumpers and settings on both charge controls I tested with.


    @ Niel- sorry, I'm exhausted so a little slow. But one 5 panel system goes to a combiner box, to the charge control, to the batteries. The second system comes to a second combiner box, to a second charge control, to the shared batteries. One of two systems set up like this (the other one somewhat older) and the other is functioning fine. And the smaller half of the malfunctioning system is working…

    2- unless I am missing something…then yes. Each panels + comes to a single breaker in the box. (Common negative bus bar). Single pole breakers.

    And no- they aren't mppt - the old trace C series.

    sorry- "neg out to common neg from control" : I meant the common negative bus bar in the breaker box is wired out to one of the two common negatives on the trace charge control (other common neg on control goes to battery - )



    I don't know. It *seems* to me everything downstream of the panels is functioning properly. I'm just perplexed why they (the panels) all seem to be reading proper voltage without producing power...
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #8
    Re: HELP! Solar Array not working.

    I'm just perplexed why they (the panels) all seem to be reading proper voltage without producing power...

    It's possible that there is voltage but very little amperage and
    its possible that the batteries are full enough...

    but it sounds like it's the "shared ' battery &/or connections &/or CC that are at issue...
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #9
    Re: HELP! Solar Array not working.

    Battery bank voltage sounds very low for a "resting battery bank". And if charging, way too low (or too low of charging current).

    Do you have a hydrometer to measure the specific gravity of the battery bank? Do you have some way of getting those guys >80% state of charge over the next day or two?

    I worry that they are going to sulfate on you if they do not get recharged/cycled properly.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #10
    Re: HELP! Solar Array not working.

    not sure ofwhat all breakers going to pv load means either, but i will assume you meant the + input from the pvs on the controller. if in doubt of the pvs then individually do a short circuit current test with a meter that can read at least the amount of short circuit current without blowing internal fuses or damage to the meter.
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  • terrapinflyer
    terrapinflyer Registered Users Posts: 8 ✭
    #11
    Re: HELP! Solar Array not working.
    BB. wrote: »
    Battery bank voltage sounds very low for a "resting battery bank". And if charging, way too low (or too low of charging current).

    Do you have a hydrometer to measure the specific gravity of the battery bank? Do you have some way of getting those guys >80% state of charge over the next day or two?

    I worry that they are going to sulfate on you if they do not get recharged/cycled properly.

    -Bill


    Yep- the battery bank has gotten drawn down by the loads. An extra 120 AH pull has been added in the past couple days- which is what helped confirm to me that something was wrong.

    Batteries are virtually brand new- and hyrgometer shows no meaningful difference between cells. (water levels ok too).

    It's been thrown on a charger to bring it up some. And two spare panels added to system (and a portion of the loads removed) until I figure out what's going on- so system should be fully recharged every day.

    Roughly 660 AH battery bank using approx 120 AH's at night.

    Resting voltage has consistently been 12.6 or so. But a couple cloudy days took the working panels out of the equation- hence the low voltage. (system is oversized with the intent of almost keeping up during a few cloudy days)
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #12
    Re: HELP! Solar Array not working.

    Whoa, resting V should be about 13,0- 13.2 (New) after 3 hr rest from charging, what are your SG readings on each cell?
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #13
    Re: HELP! Solar Array not working.

    Several things, resting voltage for 12 V FLAs at 25 degrees C is normally about 12.7 or perhaps 12.8 V. This is with NO charging and NO loads at all for hours.

    Seems that at least one thing has been done that is not good pracitice -- pulling spliced wires into or through conduit ... asking for trouble.

    Homeline breakers are not rated for DC. The Homeline series of boxes and breakers are very marginal but they are very cheap.

    HomeLine is a distinct product line from QO breakers/panels. Real QO breakers are rated to 48 V DC for ratings of 10 - 70 Amps. But believe that QO breakers will not fit HL panels/boxes. See page 7 - 2 in the below pdf :

    http://www.cesco.com/resources/785901/288363-AttachmentURL.pdf

    There may be a number of issues with this installation. Good Luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 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.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #14
    Re: HELP! Solar Array not working.
    terrapinflyer wrote: »
    I don't know. It *seems* to me everything downstream of the panels is functioning properly. I'm just perplexed why they (the panels) all seem to be reading proper voltage without producing power...
    One characteristic of solar cells is that the produce essentially the same open circuit voltage with anything from moonlight to full sun. What varies is the amount of current you can draw before the voltage collapses.
    Among other things that means that a single cell going bad (cracks, corrosion, etc.) can limit the amount of current that the whole panel can produce. (There are typically bypass diodes, but when you have only one panel instead of a series string, activating the bypass diode will reduce the voltage from the panel to the point where it is below the battery voltage. Which in turn means that instead the current will be limited to that of the worst cell.)

    Now having all five panels turn up with one bad cell is not very likely, but it does illustrate that a panel can deliver full voltage and still deliver almost no current just because of one bad cell.
    SMA SB 3000, old BP panels.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #15
    Re: HELP! Solar Array not working.

    i did advise him to check the isc of each pv as that would verify if they are working or not. up to him to rule this out.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #16
    Re: HELP! Solar Array not working.
    niel wrote: »
    i did advise him to check the isc of each pv as that would verify if they are working or not. up to him to rule this out.
    But if there is a bad cell (low current or high resistance) and the panel has bypass diodes, you can still have both normal Voc and normal Isc. Only the shape of the I vs V curve between those two points (including Imp and Vmp) will be changed.
    SMA SB 3000, old BP panels.
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #17
    Re: HELP! Solar Array not working.
    inetdog wrote: »
    But if there is a bad cell (low current or high resistance) and the panel has bypass diodes, you can still have both normal Voc and normal Isc. Only the shape of the I vs V curve between those two points (including Imp and Vmp) will be changed.
    It seems to me that if one cell were bad and bypassed, either Voc or Isc would have to be affected.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #18
    Re: HELP! Solar Array not working.
    terrapinflyer wrote: »
    Since you mention checking the panels voltage- one I was only getting 15V+ but the others 19V +/-. So I'm confused why I am getting no amps/watts in... I thought if I was reading proper voltage then the panels were indeed working?

    Assuming you are measuring VOC, with the panels not connected to the system, your single panel reading 15V likely is producing about 80% of that VMP(voltage under load, like charging your battery) since this represents only 12 Volts it isn't charging voltage for your battery (unless it becomes very low) Take this panel out of your paralleled panels.

    When in parallel, panels operate at the voltage of the lowest panel, since that was below charging voltage they will not send meaningful current to the batteries. once removed you should see some charging current. If you have no improvement you might consider running them through a different charge controller to see if that is your problem.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #19
    Re: HELP! Solar Array not working.
    ggunn wrote: »
    It seems to me that if one cell were bad and bypassed, either Voc or Isc would have to be affected.
    Not noticeably. For Isc, the bypass diodes will not limit the current, so Isc will be that of the weakest unbypassed cell.
    For Voc, a low current cell (not open or shorted) will not affect Voc at all since at no load the added resistance or lower Isc.cell will not affect the voltage.
    When you test Voc, the cell group is not bypassed, when you test Isc the bypass does not change the current. (Isc of two working panels in series is exactly the same as Isc.)
    There would be a very small change because you would be reading I at V=Vdiode instead of I at V=0. But the current voltage curve is almost vertical at that point anyway.
    SMA SB 3000, old BP panels.
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  • bmet
    bmet Solar Expert Posts: 630 ✭✭
    #20
    Re: HELP! Solar Array not working.

    "Carefully using an ohmmeter (i think he meant dvm reading amps, niel) and a switch determine the short circuit current from each panel"



    NEVER NEVER NEVER use an ohmmeter to measure Current!
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  • terrapinflyer
    terrapinflyer Registered Users Posts: 8 ✭
    #21
    Re: HELP! Solar Array not working.
    niel wrote: »
    i did advise him to check the isc of each pv as that would verify if they are working or not. up to him to rule this out.

    Thanks. Time for some reading to refamiliarize myself- as I said- electricity is not second nature to me- something I've picked up from years of off-grid living, old vehicles, massive irriigation installs, remodeling, etc... I still need to make **** sure I know, for sure, what I'm doing before I try something new or am not absolutely sure about...

    Thanks for all the replies from this community...

    One more quick question- re: a bad panel dragging down the rest in the group. Is this true if each panel is wired individually to a breaker in the box- or only if they are combined before being run to the breaker?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #22
    Re: HELP! Solar Array not working.

    If you can justify it... A Sears DC Current Clamp meter for ~$60 is a good deal for debugging problems like this (really an AC/DC clamp+Digital Multi Meter). Just put the "clamp" on one of the array wires and read the the DC current--very simple to see if all three are working or if one or more are bad.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • terrapinflyer
    terrapinflyer Registered Users Posts: 8 ✭
    #23
    Re: HELP! Solar Array not working.

    Thanks for that. I've actually never used a clamp style meter but something I've been meaning to learn. Will do my homework this weekend.

    I've never actually had anyone to teach me the finer points of meters- so trial and error which can be a dangerous thing- so I've not ventured as far as I should. (Used to have a great tutorial from the folks at backwoods solar (jim and elizabeth?) on multimeters many, many years ago.

    Time to educate myself again...
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #24
    Re: HELP! Solar Array not working.

    do you have any meters right now that can measure current up to at least 10 amperes? basically what one will do in a short circuit current test is to short the panel's full output through the meter reading in amperes. it is that simple, but be aware that making and breaking that connection will have quite an arc so it's better to have the pv covered while you make or break the connection to the meter pulling it off only to get a proper current reading in full sun.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #25
    Re: HELP! Solar Array not working.
    terrapinflyer wrote: »
    One more quick question- re: a bad panel dragging down the rest in the group. Is this true if each panel is wired individually to a breaker in the box- or only if they are combined before being run to the breaker?

    I guess no one else will say it, as far as I'm concerned in parallel they work at the lowest voltage, regardless, a panel with a VOC of 15volts isn't helping and should be removed. I suspect I can at least get someone to agree to this?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #26
    Re: HELP! Solar Array not working.

    With a PWM charge controller, there is no reason to pull a "low rated" Vmp panel. It may not help much, but it won't hurt.

    With a MPPT type charge controller (not his Trace 60--I don't think), miss-matched Vmp on panels could "confuse" a MPPT algorithm and possibly cause the controller to pick a "non-ideal" Vmp-Array.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • terrapinflyer
    terrapinflyer Registered Users Posts: 8 ✭
    #27
    Re: HELP! Solar Array not working.
    Vic wrote: »
    Homeline breakers are not rated for DC. The Homeline series of boxes and breakers are very marginal but they are very cheap.

    HomeLine is a distinct product line from QO breakers/panels. Real QO breakers are rated to 48 V DC for ratings of 10 - 70 Amps. But believe that QO breakers will not fit HL panels/boxes. See page 7 - 2 in the below pdf :

    You are correct. They're the Square D QO series breakers and panel. Not sure why I said Homeline except being a little exhausted at the time...
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #28
    Re: HELP! Solar Array not working.

    OK terra ..

    Great news. QOs are fine breakers/panels. Good luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 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.
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