Instalation/devolpment help

CavemanCaveman Solar Expert Posts: 83 ✭✭✭✭
Ok, so I'm having trouble visualizing how to build my solar setup. I don't know the first thing about fuses, wire, and the like. here's what I got:

- 2 panels (12V 140 watt each)
- 4 6V golf cart batteries

Morning star Pro star 30 controller

Inverter:Exceltech DC 12V (sys) 171 A @ 13.8V (nom) AC 117V 17.1 A 60 Hz

I don't know how to draw a schematic on my computer, so ill try to describe it here.

The 2 panels have to be about 60' from the cabin, so I will run this, (insert cable type, size, and any connectors here?) to a little room about 10 feet from the panels. Where do I need to put my fuses? What type wire? any special way the wires connect to the panels? Any resource material I could buy?

I will then run 10AWG (30 amp service) outdoor cable the 60' back to the cabin where that end of the system is already built.

I'm feeling lost, I feel like if I could see someones system and have them walk me through it, I could get it, but I don't know where to start. Anyone know of a good book?
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Comments

  • PhotowhitPhotowhit Solar Expert Posts: 5,658 ✭✭✭✭✭
    Re: Instalation/devolpment help

    I take it your not running much.

    I have had a similar setup, with an inexpensive charge controller, I will suggest setting every thing up where the panels are and run AC to the house.

    First build an 'A' structure for your panels tall enough for the bottom panels to be above growing vegetation. If your in a windy location, you will want to strongly cross brace the frame, if your not in a very windy area, you can let the solar panel frame take the stress (my thin walled Photowatt panels survived 30 year this way) Figure out how you want to attach the panels to the frame, if you use aluminum angle for the pieces behind the panels, you can just bolt them to the aluminum, if you use wood, small sections of aluminum angle can be cut to mount the panels.

    Below the 'A' section, you want a box, think cedar chest type thing. You should section the box into 2 areas, on one side you want to have your batteries. The batteries will add weight to help the panels from blowing over! Hook up the batteries in series and parallel, so you have 2 sets of batteries attached + to - and then have the 2 sets attached to each other + to + and - to -, to create a large 12 volt battery, you might like to have a fuse of breaker for each string of batteries. From If you use 4 cables all the same length to attach the batteries, you can attach the negative to one string and the positive to the other and have equal resistance across the 2 strings of batteries.

    Run cables from the battery side to the electrical side, we divide the sides since the out gassing of the batteries is corrosive to electronics. Mount your inverter and charge controller to the wall of your box. In a small system like this I would attach the battery bank cables to the inverter, If you would like you could use a switch to disconnect the inverter, or count on the inverters switch.

    Wire your panels together using MC4? 'Y' connectors then run the + and - cables into the electronics side of your box. Attach the cables to the solar input of the charge controller. From the solar output of the charge controller run your + and - lines to the first attachment point of your battery bank on the electronics side, on the battery side of the switch if installed.

    You can run with out, but it's nice to have a switch to turn off the solar array as well. From the back of your inverter, cut off the end of a heavy extension cord, 12 gauge or better and hardwire it into the back of your inverter. you could just plug it in, but it's nice to have it hardwired. run this into your cabin.

    This is pretty minimal, you could bury a direct bury wire to your cabin, or put wire in conduit. You could add breakers at the box. I suggest doing this since you have such a great distance to the cabin and you would need to run heavy wire to take the electric current at 12v to the cabin to install the electronics.

    Please note your array is very minimal for a 12v 440Ah battery bank.
    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.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Instalation/devolpment help
    Caveman wrote: »
    Ok, so I'm having trouble visualizing how to build my solar setup. I don't know the first thing about fuses, wire, and the like. here's what I got:

    - 2 panels (12V 140 watt each)
    - 4 6V golf cart batteries

    Morning star Pro star 30 controller

    Inverter:Exceltech DC 12V (sys) 171 A @ 13.8V (nom) AC 117V 17.1 A 60 Hz

    I don't know how to draw a schematic on my computer, so ill try to describe it here.

    The 2 panels have to be about 60' from the cabin, so I will run this, (insert cable type, size, and any connectors here?) to a little room about 10 feet from the panels. Where do I need to put my fuses? What type wire? any special way the wires connect to the panels? Any resource material I could buy?

    With ten feet from panels to charge controller at nominal 12 Volts and combined Imp of 16 Amps 10 AWG will work.
    I will then run 10AWG (30 amp service) outdoor cable the 60' back to the cabin where that end of the system is already built.

    What Voltage will this long wire run be at? If it's not 120 VAC or 240 VAC it is not going to work. That 50-60' distance is too long for low Voltage DC to be practical. If you put the charge controller, batteries, and inverter in the shed and then run the AC out of the inverter to the cabin it will be much better. 10 AWG would handle 120 VAC @ 15 Amps over that distance.
    I'm feeling lost, I feel like if I could see someones system and have them walk me through it, I could get it, but I don't know where to start. Anyone know of a good book?

    The problem there is that everyone's system is different.

    Your two 140 Watt panels will not be enough to charge four 220 Amp hour 6 Volt batteries on a 12 Volt system (440 Amp hours @ 12 Volts). They will work for two such batteries.
  • CavemanCaveman Solar Expert Posts: 83 ✭✭✭✭
    Re: Instalation/devolpment help

    Thanks so much for your help guys, this gives me a great starting point. The system is small I know, I can't remember why I bought 4 batteries, but I think I can return them still.
  • CavemanCaveman Solar Expert Posts: 83 ✭✭✭✭
    Re: Instalation/devolpment help

    Okay, a little confused here. I am building an off grid system with generator backup. I built a cabin and wired it all traditionally for AC power. I have a breaker box inside, and a manual transfer switch that divides the generator power from the solar.

    When I was getting the generator side up and running I couldn't keep the generator's breaker from tripping until I removed the ground wire from where I had it attached at the transfer switch. With the ground removed, everything works fine. When I bought the power cord to supply the cabin from the generator, I bought a regular 3 wire cord. Evidently now I could have just bought a 2 wire, the 3rd is doing nothing.

    Why is this?

    Also, and perhaps more importantly, do I need to buy a 3 wire cord for my 60' run back to the cabin (it will be AC power). If my system out near the panels is grounded, can I just run a 2 wire (hot & neutral) back to the cabin' plugging in to said transfer switch? (transfer switch is grounded)

    Lastly, I am going to need to run a separate cable from the generator, back to the battery charger/batteries right? Or maybe someone has an idea of how it works when I switch from PV power to generator, because it will be supplying power to both the cabin and the charger.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Instalation/devolpment help

    Details, details!

    Your gen might have an N-G bond in it and GFCI outlet connection in which case addition N-G connection "downstream" would cause instant failure. Or the ground wire was in the wrong place (99% of the time GRND just "goes through" and does NOT connect to any other wiring). Or half a dozen other possibilities. Under normal circumstances ground wiring does absolutely nothing; it's there for when something goes wrong.

    You can use one of those plug-in outlet testers to see if it's right: the gen's output should show "open ground" meaning there's no N-G bond. If it says everything is fine at the generator, then you're probably duplicating the N-G bond causing parallel current paths. Okay; you're completely lost now, right?

    Do you need a ground wire from the gen to the house over 60'? Probably. If the gen is Earth grounded at both places, though, you run up against that parallel current path problem again. Grounding is probably the most complex aspect of wiring.

    As for the AC switching, your Exeltech has no built-in charger/transfer switch. Therefor you would have the loads on a transfer switch that can have its input select either the inverter's output or the generator's output. Before that the gen's output would power the stand-alone battery charger. How automated you want to make this depends on how much fun you want to have with complicated circuits.
  • CavemanCaveman Solar Expert Posts: 83 ✭✭✭✭
    Re: Instalation/devolpment help

    I have a plug in outlet tester, but its for a regular 15A outlet, and my power cord going to the cabin is plugged in the 30A twist-lock. Does this make a difference? I am thinking not because it sounds like you are describing how the internals of the entire elec panel on the gen are wired.

    "Probably"... not what I wanted to hear, arggg haha...one of those "it depends" scenarios. The generator is not earth grounded, but the transfer switch that it is wired into, is.

    Complicated circuits aren't fun for me haha. I have the Iota DLS 15 Series M charger. I think I understand about the switching, so I need another transfer switch. Any suggestions?
  • BB.BB. Super Moderators, Administrators Posts: 32,026 admin
    Re: Instalation/devolpment help

    Generators may have two types of circuit breakers... One is a simple "too much current" and it will trip--Usually, for these to trip quickly (minutes or faster), the over current has to be pretty significant (25-50% or even more).

    The other is the Ground Fault Interrupter (GFI)... This measures the "total current" out the AC power cord (black and white, hot to neutral, etc.). This will trip with ~0.005 amps (5 milliamps) or so... A typical fault condition is that the Neutral is tied to the generator green wire inside the generator (fine by itself). And the neutral is tied to green wire / earth ground at the main panel in the cabin (also fine by itself). Some AC inverters may also tie the Neutral to green wire internally (again, fine by itself).

    The problem is when there are earth/neutral ties "beyond" the GFI protected outlet. To the GFI circuit, it looks like there is AC output to green wire fault (and there is). So, the fix is to "address" the neutral/ground bonding issue (not always easy or straight forward).

    So, is the generator's GFI output tripping, or is it the Over Current breaker that is tripping.

    And if it is the over current breaker, is the AC inverter somehow connected when the generator is running?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Instalation/devolpment help

    Okay, how close is this to your generator connections?
    It has two 120 VAC standard plugs on top and a 30 Amp 240 VAC twist-lock below.
    Note the "push to reset" breakers.
  • CavemanCaveman Solar Expert Posts: 83 ✭✭✭✭
    Re: Instalation/devolpment help

    This is what mine looks like for now, I know its over sized for the job, but it's one I already had.Attachment not found.Attachment not found.
  • CavemanCaveman Solar Expert Posts: 83 ✭✭✭✭
    Re: Instalation/devolpment help

    Man that pic didn't post very well, let me try again.

    Attachment not found.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Instalation/devolpment help
    Caveman wrote: »
    This is what mine looks like for now, I know its over sized for the job, but it's one I already had.
    I have a similar panel on my generator. Only caveat is that the 120v 30A output is on one side of the 240 while the two 20A duplex receptacles are one on each side. Have to be careful which you choose to use at the same time as the 30A or you will overload one winding.
    SMA SB 3000, old BP panels.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Instalation/devolpment help
    Caveman wrote: »
    Man that pic didn't post very well, let me try again.
    It went fine. You just have to click on the thumbnail to see it full size.
    SMA SB 3000, old BP panels.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Instalation/devolpment help

    I see relevant information there:

    1). "Neutral bonded to frame." (Sounds like an N-G bond to me; all it lacks is the rod in the ground.
    2). One outlet is a 120 VAC twist-lock, another is a 240 VAC twist-lock.
    3). "All outlets GFCI protected".

    Now, how many of these were we talking about before? ;)
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Instalation/devolpment help
    I see relevant information there:

    1). "Neutral bonded to frame." (Sounds like an N-G bond to me; all it lacks is the rod in the ground.


    Now, how many of these were we talking about before? ;)
    +1
    Whether the frame is connected to a separate earth ground or not, what counts is that the EGC and the neutral are tied together on both sides of the GFCI, allowing a very good neutral current path around the GFCI, which is just what it is supposed to detect.
    SMA SB 3000, old BP panels.
  • CavemanCaveman Solar Expert Posts: 83 ✭✭✭✭
    Re: Instalation/devolpment help

    If you look at the first 2 photos I sent, you can see which one I have the cabin plugged into. It's a 3 wire cord (hot, neutral, ground) but where the cord is wired at the transfer switch at the cabin, the ground is disconnected. Wouldn't work any other way. Is this a concern?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Instalation/devolpment help
    Caveman wrote: »
    If you look at the first 2 photos I sent, you can see which one I have the cabin plugged into. It's a 3 wire cord (hot, neutral, ground) but where the cord is wired at the transfer switch at the cabin, the ground is disconnected. Wouldn't work any other way. Is this a concern?

    What you've got is no ground on the generator. That could present a shock hazard.

    Normally you'd have the generator output of Hot, Neutral, and Ground feeding the transfer switch as three separate wires. The N-G bond and ground rod would be on the distribution side; after the transfer switch. No GFCI circuit, no N-G bond at the generator.

    What you've got is a gen meant to be "fully portable" rather than hardwired. It's Neutral is connected to ground, and after that it has GFCI circuit. Put a ground rod on it and its outputs become "household quality" with proper ground, bond, and GFCI.

    Trouble is when you connect it to a distribution center with its own N-G bond you create a parallel path around the gen's GFCI circuit through the ground wire. By removing the ground wire at the transfer switch you eliminate that problem, but now the gen's ground is not, in fact, grounded. It is still connected to the gen Neutral, which means that in respect to real ground the frame of the gen is "live" because Neutral isn't grounded.

    If that sounds like a nightmare of mixed-up wiring it's because it is.

    Best case would be to remove the N-G bond at the transfer switch, and reconnect the ground from the gen. Trouble is if you disconnect the gen then there is no N-G bond on the rest of the system. This calls for the kind of 3-wire transfer switch found on some RV installs, so that when the transfer switch is in "GEN" position the only N-G bond is at the gen itself, and when flipped to "INV" the switch forms an N-G bond to protect the rest of the wiring while running on inverter.

    That's kind of complex so I may have to do a drawing.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Instalation/devolpment help
    Caveman wrote: »
    The generator is not earth grounded, but the transfer switch that it is wired into, is....
    A common misconception is that the safety ground wire works by creating a path to earth ground. It actually works (except for lightning) by creating a path that fault current can follow back to the supply to trip the breaker if a hot line contacts exposed metal on the outside of an appliance or tool.
    It is also a good idea (and required if you have to follow NEC) to connect the safety ground wire to an actual earth ground. But a ground-wire to neutral bond at the generator will cause GFCI tripping even if you do not connect the generator to a ground rod or other ground electrode.
    If there is also a ground to neutral bond at the transfer switch, or also one on the house wiring side of the transfer switch, or even one somewhere on the other side of the transfer switch if the switch does not interrupt the neutral wire, then a GFCI at the generator will trip.
    SMA SB 3000, old BP panels.
  • NorthGuyNorthGuy Solar Expert Posts: 1,913 ✭✭
    Re: Instalation/devolpment help
    Caveman wrote: »
    If you look at the first 2 photos I sent, you can see which one I have the cabin plugged into. It's a 3 wire cord (hot, neutral, ground) but where the cord is wired at the transfer switch at the cabin, the ground is disconnected. Wouldn't work any other way. Is this a concern?

    Looks like you have neutral to ground bond in your main panel at the cabin. If you now connect generator's frame to the ground, for example by placing it on a wet soil, you're completing a circuit neutral-ground-frame-neutral. This will immediately trip GFI inside the generator.

    If I were you, I would remove the bond between neutral and generator frame, and re-connected ground at the cabin. This would effectively disable GFI protection, but everything would be grounded.

    I had a Champion generator, and they had instruction on neutral to ground bond removal on their web site. So, I did it.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Instalation/devolpment help
    NorthGuy wrote: »
    If I were you, I would remove the bond between neutral and generator frame, and re-connected ground at the cabin. This would effectively disable GFI protection, but everything would be grounded.

    This will not exactly disable the GFI protection. Just as you can use a GFCI receptacle on a two wire circuit, the GFI at the generator will still be able to detect any imbalance in the current on the hot and neutral leads. But without the ground-neutral bond at the generator the current flow at the generator will be matched even if current is flowing into the equipment ground inside the cabin.
    But if you want to keep GFCI protection, you should leave the bond at the generator and remove it at the cabin.
    The problem this will cause is that when you flip the transfer switch to go to the inverter, your ground neutral bond will still be there, but will go away if you unplug the generator.
    Replacing the generator with a dummy plug which just bonds ground to neutral will preserve this necessary bond. But it will not allow GFCI protection in the inverter (if any) to work properly.
    :-)
    SMA SB 3000, old BP panels.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Instalation/devolpment help

    :confused:Was my explanation that confusing? Or too long? Or badly worded?
  • CavemanCaveman Solar Expert Posts: 83 ✭✭✭✭
    Re: Instalation/devolpment help

    Well maybe so... I think i'm getting some of it. I'm pretty sure my neutral and ground bars are all separated, but I'll check again this afternoon.
  • BB.BB. Super Moderators, Administrators Posts: 32,026 admin
    Re: Instalation/devolpment help

    My own suggestion would be
    • bypass the GFI outlets on the genset (bypass the GFI sensor/breaker, etc.)
    • Make sure you have a single Neutral to Earth bond (to ground rod) if appropriate (not all inverters support grounded neutrals, etc.)
    • For your home/cabin's AC wiring, install branch circuit GFI or outlet GFI where required.

    One of my concerns with generator/main inverter GFI is that if there is a GFI fault anywhere in the building, the whole building it plunged into darkness.

    Having a per outlet/branch circuit GFI, only that circuit shuts down, and the the rest of the building lighting/etc. goes on as normal.

    Also can help with finding a GFI fault--It is now limited to a specific outlet or branch circuit, rather than somewhere in the entire AC wiring path.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Instalation/devolpment help

    I quite agree with Bill: GFCI should be implemented at the point of use, not and the power source.

    However, taking apart a generator and changing its wiring will definitely void the warranty and may be too complicated a procedure for some people.
  • NorthGuyNorthGuy Solar Expert Posts: 1,913 ✭✭
    Re: Instalation/devolpment help
    ... changing its wiring will definitely void the warranty.

    Not necessarily. When I bought Champion generator, I was able to download detailed instructions for removing neutral to ground bond. It did say that once it's done the generator will not comply with CSA for portable generators, but it didn't say it would void the warranty.

    People definitely shouldn't do any modifications if they don't feel comfortable with what they're doing.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Instalation/devolpment help
    NorthGuy wrote: »
    Not necessarily. When I bought Champion generator, I was able to download detailed instructions for removing neutral to ground bond. It did say that once it's done the generator will not comply with CSA for portable generators, but it didn't say it would void the warranty.

    People definitely shouldn't do any modifications if they don't feel comfortable with what they're doing.

    I was referring to Bill's suggestion of GFCI and N-G bond removal. If the gen comes with instructions on how to change it for different needs that should not void the warranty (because the company is telling you exactly what to do).
  • CavemanCaveman Solar Expert Posts: 83 ✭✭✭✭
    Re: Instalation/devolpment help

    Here is my AC Panel; the orange Romex at the top is from solar (via the transfer switch). The orange romex with the blue wrapped wire is from the generator (via the transfer switch).
    Attachment not found.
  • CavemanCaveman Solar Expert Posts: 83 ✭✭✭✭
    Re: Instalation/devolpment help

    Here they are in proximity
    Attachment not found.
  • CavemanCaveman Solar Expert Posts: 83 ✭✭✭✭
    Re: Instalation/devolpment help

    Here's a better view of my transfer switch. Now that I look at it I can see how the neutral could be connecting to ground.
    Attachment not found.
  • NorthGuyNorthGuy Solar Expert Posts: 1,913 ✭✭
    Re: Instalation/devolpment help
    Caveman wrote: »
    Here they are in proximity

    This doesn't look like a transfer switch. These are two DPST switches (breakers?). Looks like only one side is used, which disconnect solar and generator independently. If you turn on both, it may not be good for either generator or inverter.

    Transfer switch is DPDT. You would connect two wires from solar to one end and two wires from generator to the other end. Then you would run two wires from the transfer switch to your AC panel.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Instalation/devolpment help

    Looking for the N-G bond.
    See that deep-set screw in the middle of the neutral bus bar at the top of the breaker box? That looks very much like one of the methods the bond is made: turn the screw in until it makes contact with the (grounded) box. If you turn it out and have the transfer switch set to 'inverter' (and/or gen input disconnected) there should be no continuity between the ground bus bar at the bottom and the neutral bus bar at the top.

    Odd looking "transfer switch". It appears as two breakers, one for each power source connected to common output to the breaker/distribution box. :confused: I admit to having difficulty seeing these pictures, but they don't look like the way this sort of thing is normally done. I would expect to see output from gen and output from inverter go into the transfer switch box, with one set of wires coming out of that to feed the breaker.

    I think we need a schematic of this wiring.
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