Need help in assembling solar panel system

mulia
mulia Solar Expert Posts: 62 ✭✭✭✭
Hi everyone,

I'd like to ask for everyone to help me in determining and helping to find any bug in system which I'm going to assembly soon.

Last time I posted here, there have been so many members and moderators giving their helps to enlightening me about harvesting energy from sun, I do hope now you'll keep helping me.

The diagram is as below
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Diagram

Pardon me for this blurry large image.

5x 100 watt panels will be connected to Classic 150 charge controller through 2x4mm2 (about AWG11) NYY Cable.

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2x4mm NYY

Each panel will be protected by 12A breaker. Distance between panels to CC are around 8 metres. (according to calcu*****.net voltage drop is 0.40%, please share it if you've other opinion)

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12A Breaker

At the moment, I haven't use any combiner box yet, I've ordered a combiner box, it's still on the way, so I'll just combine those 5 cables from panels into 1 any shrink tube it. (for now)


The CC will be connected to the battery bank using 2x16mm2 (about AWG 5) NYY cable. Classic max cable size is 20mm2.

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2X16mm2 NYY

4 T105 plus will be connected series and parallel to gain 12V 450AH using 25mm2 welding cable (about AWG4) please share your opinion about the cable, they finally arrived after months of waiting...


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25mm2 cable crimped to lug using a crimper

As for the inverter, a Suresine 300 will be connected to the battery using 25mm2 Welding cable, the same one used to interconnect. A 100A fuse will be placed at positive.


Finally, it's time to ask for your opinion regarding the cabling and assembling and anything you found......suspicious...

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    mulia wrote: »
    Each panel will be protected by 12A breaker. Distance between panels to CC are around 8 metres. (according to calcu*****.net voltage drop is 0.40%, please share it if you've other opinion)

    I think you have about:

    Voltage drop: 0.37
    Voltage drop percentage: 2.06%
    Voltage at the end: 17.63

    Did you change the operating voltage to ~18 volts Vmp? The default is 120 volts.

    That is not an excessive amount of drop--But with an MPPT charge controller, you could use 2x panels in series (2/4/6/etc. panels total) that would give you lower percentage voltage drop and work a little better with on very hot days (panel Vmp falls as they get hot).
    mulia wrote: »
    The CC will be connected to the battery bank using 2x16mm2 (about AWG 5) NYY cable. Classic max cable size is 20mm2.

    If I got the calculations correct, the voltage drop would be (assuming 500 watt array, 2 meter cable, 5 awg, 14.5 volt battery charging).:

    Voltage drop: 0.17
    Voltage drop percentage: 1.17%
    Voltage at the end: 14.33

    Personally, I would suggest a maximum voltage drop of 0.05 to 0.10 volts (for a 12 volt battery bank). You should use a shorter cable (less than 2 meters) and/or heavier cable. 1/2 the length would give you 0.17/2 = 0.085 volt drop,

    Do you have a fuse/circuit breaker between charge controller and battery bank?

    Keep all 12 VDC battery cables short and heavy. Ideally, for your loads, you would want around 0.5 volt drop maximum from battery to loads/AC inverter/etc...

    Looking good.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mulia
    mulia Solar Expert Posts: 62 ✭✭✭✭
    BB. wrote: »

    I think you have about:

    Voltage drop: 0.37
    Voltage drop percentage: 2.06%
    Voltage at the end: 17.63

    Did you change the operating voltage to ~18 volts Vmp? The default is 120 volts.

    That is not an excessive amount of drop--But with an MPPT charge controller, you could use 2x panels in series (2/4/6/etc. panels total) that would give you lower percentage voltage drop and work a little better with on very hot days (panel Vmp falls as they get hot).
    .

    Ah... sorry... my mistake.. I did change the operating voltage, but I mistook Voltage drop as Voltage drop percentage...

    Yes.... As soon as this long planned system working properly, I'll order 3 more 150W panels to be able to allign them in series besides to support charging, I wish my MNPV06 combiner arrive faster....

    BB. wrote: »

    If I got the calculations correct, the voltage drop would be (assuming 500 watt array, 2 meter cable, 5 awg, 14.5 volt battery charging).:

    Voltage drop: 0.17
    Voltage drop percentage: 1.17%
    Voltage at the end: 14.33

    Personally, I would suggest a maximum voltage drop of 0.05 to 0.10 volts (for a 12 volt battery bank). You should use a shorter cable (less than 2 meters) and/or heavier cable. 1/2 the length would give you 0.17/2 = 0.085 volt drop,

    Do you have a fuse/circuit breaker between charge controller and battery bank?

    Keep all 12 VDC battery cables short and heavy. Ideally, for your loads, you would want around 0.5 volt drop maximum from battery to loads/AC inverter/etc...

    Looking good.

    Thanks for pointing it out. I'll put the CC nearer to the battery bank if possible or I'll get 20mm NYA cable to connect CC to battery bank, it's acceptable to use NYA cable?

    I don't have fuse/breaker between CC and battery bank, do they need one? I though Classic have provided this protection.

    If it's needed, with 45A charging, should I put a 50A fuse?

    Btw, Suresine will high volt disconnect at 15.5 while T105 equalize at 15.5. Will Suresine keep disconnect overtime when battery is fully charged?

    I have a plan to give 0.5V voltage drop from BB to Suresine in order to make Suresine assume that the voltage is only 15V therefore prevent high voltage disconnect, is it okay or it's bad idea?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    mulia wrote: »
    Thanks for pointing it out. I'll put the CC nearer to the battery bank if possible or I'll get 20mm NYA cable to connect CC to battery bank, it's acceptable to use NYA cable

    I do not know anything about those standards... Basically, you want to look at :
    • voltage rating (not usually an issue for low voltage DC)
    • temperature of environment (and temperature rise of wire--but with low voltage drop, not usually a problem)
    • Chemical resistance (oil/water/etc. for your application, if any)
    • Sun/UV resistance (if exposed to direct sun/through window--UV is very hard on plastics/insulation).
    • Abrasion resistance--Make sure sharp edges/saw edges are smoothed/bushing to prevent cutting of insulation, wire does not move on rough surface, etc.
    I don't have fuse/breaker between CC and battery bank, do they need one? I though Classic have provided this protection.

    A fuse/breaker near source of high current (almost always the battery bank in DC power systems) is used to protect the wiring... If there is a short between the battery and the charge controller, fusing inside the controller will not prevent the wire from getting red hot/starting a fire.
    If it's needed, with 45A charging, should I put a 50A fuse?

    For North American standards, you need to take the rated continuous current and multiply by a minimum of 1.25x for fuse/wire rated current:
    • 45 amps * 1.25 = 56.25 ~ round up to next available standard (like 60 amps)
    Btw, Suresine will high volt disconnect at 15.5 while T105 equalize at 15.5. Will Suresine keep disconnect overtime when battery is fully charged?

    From some specs. I found online:
    • High Voltage Disconnect (HVD) – The SureSine will shut down and disconnect AC Output if battery voltage exceeds 15.5V. Automatic reconnection when battery voltage decreases to 14.5V.
    I have a plan to give 0.5V voltage drop from BB to Suresine in order to make Suresine assume that the voltage is only 15V therefore prevent high voltage disconnect, is it okay or it's bad idea?

    The 0,5 volt drop is only at high AC loads--I.e., the inverter draws (you can use the 300 Watt limit or the 600 Watt 10 minute limit--your choice based on your loads for designing voltage drop/wire size):
    • 300 watts * 1/0.85 typical eff * 1/10.5 battery cutoff = 33.6 amps
    So, you may have 0.5 volt drop at 300 Watts, but only 0.05 volt drop at 30 Watts. Not probably a "reliable" voltage drop for the inverter.

    You can probably charge to a maximum of 15.4 volts or less in most situations/most of the time. If you ever have to equalize at 15.5+ volts--That should only be needed once a month for a few hours (at most).

    Would it be nice MorningStar made the high cutoff at 16.x volts--Yea...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mulia
    mulia Solar Expert Posts: 62 ✭✭✭✭
    BB. wrote: »
    A fuse/breaker near source of high current (almost always the battery bank in DC power systems) is used to protect the wiring... If there is a short between the battery and the charge controller, fusing inside the controller will not prevent the wire from getting red hot/starting a fire.

    For North American standards, you need to take the rated continuous current and multiply by a minimum of 1.25x for fuse/wire rated current:
    • 45 amps * 1.25 = 56.25 ~ round up to next available standard (like 60 amps)


    You can probably charge to a maximum of 15.4 volts or less in most situations/most of the time. If you ever have to equalize at 15.5+ volts--That should only be needed once a month for a few hours (at most).

    Would it be nice MorningStar made the high cutoff at 16.x volts--Yea...
    -Bill

    I'll find automotive fuse for 60A tomorrow... I'll stuff it to my fuse holder.

    Yes indeed, Morningstar need to increase the disconnect voltage. It's annoying... At least let us change the setting,,

    I just crimped interconnect cable... What's your opinion about those? It's already well crimped or not?

    Attachment not found.

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    Here is crimping tool I used to crimp them..

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    If it's to passed industrial standard, it won't since I cut the cable using steel saw and strip insulation using knife...

    But I wonder it will work well and won't pose danger/hazard to the system..
  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    Crimp looks good. As long as you did not nick the wire(s) and do a good pull test on the connector (you should not be able to pull the wire from the crimp--XX lbs of pull).

    Here is an example of pull test and pass values:

    http://www.molex.com/pdm_docs/ats/TM-640160065.pdf

    Regarding the 60 amp fuse--The automotive type fuses have been known to overheat/fail at less than rated values:

    Attachment not found.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mulia
    mulia Solar Expert Posts: 62 ✭✭✭✭
    BB. wrote: »
    Crimp looks good. As long as you did not nick the wire(s) and do a good pull test on the connector (you should not be able to pull the wire from the crimp--XX lbs of pull).

    Here is an example of pull test and pass values:

    http://www.molex.com/pdm_docs/ats/TM-640160065.pdf

    Regarding the 60 amp fuse--The automotive type fuses have been known to overheat/fail at less than rated values:

    Attachment not found.

    -Bill

    It's really a good handbook. I've read several sections of it and found my crimp...... quite acceptable for home use. :D

    So what fuse/breaker do you suggest me to use?

    Should I order another midnite breaker?

    I found that they have breaker rated 63A.

    It'll take about 2 weeks to arrive here.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    From our host NAWS, here are some 60 amp breakers:

    http://www.solar-electric.com/catalogsearch/result/?q=60+amp+DC++breakers&cat=0

    If you can find local sources--Marine and heavy truck parts stores--May be better for you.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mulia
    mulia Solar Expert Posts: 62 ✭✭✭✭
    BB. wrote: »
    From our host NAWS, here are some 60 amp breakers:

    http://www.solar-electric.com/catalogsearch/result/?q=60+amp+DC++breakers&cat=0

    If you can find local sources--Marine and heavy truck parts stores--May be better for you.

    -Bill

    Okay, It's hard to find any good quality product in my country. Most people prefer cheap-random-branded made in China product.

    Attachment not found.
    My interconnect finished... I hope the extra few cm length won't making any problem, will it?

    Few cm of bare copper appeared at the end of lug because I haven't get my shrink tube yet, is it okay to use isolation tape first?

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    It's read as approx. 12.3V. I think it's too low.. :-s Perhaps this multitester isn't working properly.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    12.3 volts is too low for a charged battery--But you don't know if the meter is accurate or not.

    The extra few CM is not going to hurt/change anything.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mulia
    mulia Solar Expert Posts: 62 ✭✭✭✭
    I'm afraid if the meter accurate or at least near, it means the batteries are in grave danger..

    They've traveled thousands kilometers from US to here. I assumed low voltage are happened because of long time without charging or trickle.

    I've installed the classic near BB, it's now less than 1 meter (about 90cm). There should be no problem anymore with voltage drop.

    Attachment not found.

    The new problem I met is cable from panel will hardly gain entry to home.

    I need to drill 5 holes from each cable to enter building.

    If I'm to use available hole used as window when building this home, then there will be added distance 3 meters from panel to CC and that's too much voltage drop.

    I wonder if there is any fix to this situation... Or I have no choice than drilling 5 14mm2 hole for cables (2x4mm2).

    Perhaps combining them in series and parallel, but with 5 panels, how can it be done?

    Vmp Imp from 2 series and 2 parallel panel are parallelized to 1 panel

    38V 10A + 19V 5A = 38V 15A?

    and I still able to use 2x4mm2.

  • mulia
    mulia Solar Expert Posts: 62 ✭✭✭✭
    Attachment not found.
    Connecting cable to the classic


    Using 16mm2 cable for 4 port of classic. The holes provided are really small, on manual, max cable size is 20mm2, 16mm2 of mine need lots of struggle to enter it. :-s

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    I'm interconnecting(jumper) them just using 4mm2 cable, is it okay? or will it post danger? Max current expected to be 30A. I think this need to be clarified by expert here. Please do share your opinion to help me.

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    I'm using terminal block to combine negative wire from PVs and connecting PV plus wire to classic after taking the wire from breaker. Will it be acceptable? The block rated 60A.

    The panel producing 20V at current time (17:40PM), they seems to be working excellent. Don't they?

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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    man, you have to put protective bushings on the chassis knockout holes, or you have a dangerous possibility of a cable short to chassis.
    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 ,

  • mulia
    mulia Solar Expert Posts: 62 ✭✭✭✭
    How can the cable short to chassis? Is it by nicked cable? I can't find anyone here selling protective bushing.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    Yep... Always assume the worse. Over the years, the cables get moved around by people walking by/working on the system and the relatively sharp edge of the box eventually cuts through the cable jacket.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    mulia wrote: »
    How can the cable short to chassis? Is it by nicked cable? I can't find anyone here selling protective bushing.

    You might just put some electrical tape on the wires going through the knock out, this will give something to chew on... or check out where ever locals get electrical supplies for strain reliefs; they look like this; There are other types, fancy water proof models, etc. Your charge controller will draw air in trough the knock outs, so unless you live in a pretty dust and bug free environment, I would install the 3 screened knockout covers that came with the Classic!

    Attachment not found.

    Just the fan vibration over time will create a sawing effect
    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.
  • mulia
    mulia Solar Expert Posts: 62 ✭✭✭✭
    Good idea, I've put electrical tape around those wires leaving classic right where they meet knock out. I've also install 2 knockout cover provided by classic after rearranging wires, it's so hard for 16mm2 to enter DC terminal of classic. Can't use 3 of them since I need to use 2 holes.

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    I'd like to ask if it's normal for cc to equalize for 4 days? It's been 3 days equalize and today classic already stop equalize and I saw it in float mode until I failed to connect to classic using ethernet bridge and decided to restart it and suddenly it is now on EQ MPPT mode again.. :-s Is it normal or something wrong? Do I need to force stop eq??

    I wonder if my CC actually know when my BB already fully charged. Do I need to buy battery meter or whizbang?

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  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Well I can't blow up the photos to read the info off the classic software, and I can't figure out how to PM Bill in this ever more frustrating forum software! AAAARRRRGGGGHHHH!

    As to the 4 wires, typical installs will have 5 wires, but 2 of them will be smaller gauge, battery temperature sensor and ground wire. Most people wire to a common DC negative buss bar. In coming solar negative will connect here, and battery will connect to the shunt(the blue thing to the left attached to the bus bar) Picture is from the manual, the 2 connectors in the middle are bonded.

    Attachment not found.
    This is what it looks in my system;
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    I cropped this out of another illustration I was doing, The bus bar here is bonded to one side of the shunt (a shunt is a connection with a very precise known resistance)

    The to 2 wires into the bus bar are my incoming arrays, the bottom 2 are from/to my classics, on the shunt next to the bus bar is my inverter cable, on the other side of the shunt is the lead to my battery bank. If you installed a Whiz Bangjr It would attach to the shunt.

    The wires at '3' are going to and from my Midnite Classics(2) the black wires going up are the breaker from the positive out put from the classics(going to breakers before going to the positive bus bar), the red wires are the positive inputs from the arrays(from the breakers), the green wire is the ground wire for the body of the classics. The blue wire are for the battery temperature sensors.


    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.
  • mulia
    mulia Solar Expert Posts: 62 ✭✭✭✭
    Photowhit wrote: »
    Well I can't blow up the photos to read the info off the classic software, and I can't figure out how to PM Bill in this ever more frustrating forum software! AAAARRRRGGGGHHHH!

    Well, I agree this forum software..... a bit frustrating.... please keep patience... :D
    I've PMed Bill already, helped so much..
    Photowhit wrote: »

    As to the 4 wires, typical installs will have 5 wires, but 2 of them will be smaller gauge, battery temperature sensor and ground wire. Most people wire to a common DC negative buss bar. In coming solar negative will connect here, and battery will connect to the shunt(the blue thing to the left attached to the bus bar) Picture is from the manual, the 2 connectors in the middle are bonded.

    I cropped this out of another illustration I was doing, The bus bar here is bonded to one side of the shunt (a shunt is a connection with a very precise known resistance)

    The to 2 wires into the bus bar are my incoming arrays, the bottom 2 are from/to my classics, on the shunt next to the bus bar is my inverter cable, on the other side of the shunt is the lead to my battery bank. If you installed a Whiz Bangjr It would attach to the shunt.

    The wires at '3' are going to and from my Midnite Classics(2) the black wires going up are the breaker from the positive out put from the classics(going to breakers before going to the positive bus bar), the red wires are the positive inputs from the arrays(from the breakers), the green wire is the ground wire for the body of the classics. The blue wire are for the battery temperature sensors.

    Thank you Photowhit, it's really detailed and helped. Your system looks so tidy, unlike mine. I haven't even have my ground rod installed therefore no grounding have made in this moment.

    I wonder if Shunt is a really crucial to use? I want to buy it, along with Whizbang, but they're quite pricey. :-s

    Another problem I have here is my array of 500W panel only producing max 200-ish watt as showed in classic, I wonder why the efficiency is so low. Are you ever having such problem?
    Do you have any suggestion regarding this problem?