Gulf Island Off-Grid System - Part 4

The system at our cabin (see Part 1, Part 2) has remained pretty much unchanged (we finally put a protective box around the batteries), but we've been making significant progress on our second solar system for our guest house/shop (See Part 3 for our initial design concepts).

Solar Array Under Construction

After much searching, we were able to find the best compromise between proximity to the building, solar exposure and minimizing the number of trees that we'll have to cut down. We sure do envy our neighbours, who have this beautiful south-facing bluff that is just perfect for solar!

So, here's the progress on the array so far:

attachment.php?attachmentid=4984

We opted to use concrete filled sonotubes and heavy aluminium "L" bars to reduce the amount of concrete while still providing a good foundation for the array, as we can get some fairly significant snow loading (local climactic data says that the combined snow and rain load, with wet snow representing the worst-case loading, can approach 46 pounds per square foot!). The site is a solid rock outcropping, so that also helps.

Here's a closer look at the west side of the array:

attachment.php?attachmentid=4985

We have 24 Sharp ND-H235Q2 panels that we'll be mounting in a 3x8 configuration. Electrically, they will be cabled into two strings, with each string connected to a SMA Sunny Boy 3000TL-US inverters (we originally were going to be using two Sunny Boy 2500HF-US inverters, but SMA recalled them for off-grid use).

The string calculations all seem to work out with lots of headroom:

For worst case voltage, we take the panel Voc (37.2v), multiply it by 12, then by 1.2 for overvoltage. That gives us 535.7 volts, which is well below the maximum rated voltage of 600 volts. So, we're good there.

For max power, we take the rated power Pmax (235w) and multiply it by 12. That gives us 2820 watts. The max power rating for the 3000TL-US is 3200 watts, so we're good there too.

As an aside, we typically _really_ poor sun conditions, and we've never seen anything close to the rated panel power from our existing panels (we're lucky if we get 60% of the rated power on the best, most sunny day given our location). During very cold weather, we might get a higher then 100% current rating, but that is also the time of the year when we get the weakest sun due to it being very low to the horizon.

For max amperage, we take the maximum power amperage Imp (7.81a), and with only a single string, that is well below the 15 amp rating.

And, finally, for minimum voltage, we take the maximum power voltage Vpm (30.1) and multiply that by 12. That gives us 361.2 volts, which is well above the 150 v rating of the inverter.

Power Container Progress

The shipping container arrives today, and the SMA Sunny Islands and Smartformer already arrived a few weeks back. The welder is ready to start making the required modifications to the container, so we should start seeing some substantial progress on this front too.

Inverters on the ferry:

attachment.php?attachmentid=4986

We're certainly looking forward to seeing more progress, and working towards getting everything up and running in time for the summer!

Attachment not found. Attachment not found. Attachment not found.
House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
«13

Comments

  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    More progress:

    attachment.php?attachmentid=5025

    The trees blocking the ridge where we built the array are now down, and we have good sun from sunrise until 2:30 in the afternoon.

    This also provides us with plenty of room for adding another array, and some nice places to plant some fruit trees. ^_^

    attachment.php?attachmentid=5026

    I've started to rough in the panel to connect the two Sunny Boy inverters together, and allow them to be disconnected when not generating power. This panel will sit beside the two inverters under the array.

    attachment.php?attachmentid=5027

    The wall dividing the generator compartment from the inverter/battery compartment is now half done, as are the hangers for attaching the plywood to the container wall.

    We also have a final location for the container, which allows us to figure out all of our cable runs.

    Attachment not found. Attachment not found. Attachment not found.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • BB.BB. Super Moderators, Administrators Posts: 28,142 admin
    Re: Gulf Island Off-Grid System - Part 4

    It may be too late now--or not work in your present plans (i.e., better security for locked metal building/container)... But be really careful about placing your generator+battery bank+electronics all in one location. Generators do have a nasty failure mode that involves lots of fire and fuel--Which, if it happens--Would take out your entire off grid power system.

    Placing fuel, genset, balance of system, solar array, etc., in separated structures helps to limit damage if the worse happens.

    Assuming you continue with your genset in the present location, look at ensuring that fuel lines cannot detach, that you setup a fire detection system that can turn off fuel pumps/turn off an electric valve to stop fuel from flowing into the structure, etc. Possibly installing a manual (or automatic?) fire suppression system/way that you can discharge a fire suppression system into the container and not risk your life (i.e., access ports/doors from outside the container/plumbed fire suppression).

    I know we have a few fire fighters here that have much more experience than I (which is none)--And perhaps they can give more exact advice and/or suggest a website to consult.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    Re #3 - We would have liked to have had a separate structure for the generator, but it would have been a significant increase in cost.

    We're have a carbon monoxide alarm that we're planning to install (which is a must for any enclosed space), but we don't anticipate there will be significant fire risks since we'll only run the generator with the container doors open, and we're not going to have auto-start or have the generator run when we're not on the property.

    We also don't intend to have any fuel storage/lines/pumps external to the fuel tank that is part of the generator, so that should reduce the fire risk substantially.

    One option that we are considering is to use a little Honda EU3000 instead of the big 6 KW diesel generator we already have. Given that we only need 20 amps, it looks like it would be cheaper and more efficient to run, and would be portable enough for us to disconnect and wheel over to parts of our property that are out of extension cord distance. If we went down this route, we could even move the generator just outside the container (to the covered entranceway) when it is being run.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • westbranchwestbranch Solar Expert Posts: 5,114 ✭✭✭✭
    Re: Gulf Island Off-Grid System - Part 4

    if you can lower that 20A to about 14 simultaneous, an Eu2000 might work better as a portable...
     
    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
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    Re #5 - Unfortunately, 20 amps is the minimum that we can go for the generator.

    The container divider and plywood is now completed. Here's a quick rendering of what the electrical equipment will look like when mounted:

    attachment.php?attachmentid=5039

    Attachment not found.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    The container is starting to come together:

    attachment.php?attachmentid=5073

    Some changes from the previous diagrams include using two raceways instead of one, and using enclosures that are the same size as the SMA Smartformer. Also of note is the unexpectedly large size of the 400 amp load centre (shown on the far right).

    The batteries will sit on the far left of the container, where the workbench is currently located.

    Attachment not found.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • NorthGuyNorthGuy Solar Expert Posts: 1,925 ✭✭
    Re: Gulf Island Off-Grid System - Part 4
    The container is starting to come together:

    Looks very neat.
    Also of note is the unexpectedly large size of the 400 amp load centre (shown on the far right).

    400A sounds like a lot of power. Would be good for 96kW. Why did you use the load center this big? Why did you put the load center into the container?
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    Re #8: As the SMA system is an AC coupled (with various power sources all connected together into an AC mini-grid), we needed to size the load centre based on the worst-case sum of all of the planned power sources feeding into the load centre in order to ensure that the bus bars could never be overloaded. It's unlikely that this would ever happen, but it's required in order to meet code, and is based on the breaker sizes, rather than the actual power we'll see from the various components of our system.

    Here's our calculations:

    Sunny Islands - 60 amp breaker
    6 KW Solar Array A - 30 amp breaker
    Generator charger - 15 amp breaker
    6 KW Solar Array B (future) - 30 amp breaker
    5 KW Wind Turbine (future) - 30 amp breaker
    Inter-tie to second building (future) - 60 amp breaker

    This sums up to 225 amps, and we wanted to make sure we still had some headroom, so we ended up going with a 400 amp panel. It also gives us lots of room for current transformers for metering, shunt trip breakers, etc.

    As the container is going to be located in a fairly central location on our property (equidistant from our solar panels, our two buildings, and our possible wind power site), it made sense to put the load centre there, as it ended up significantly reducing the cost of the Teck cable we would have needed if we ran everything into one of the buildings.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Gulf Island Off-Grid System - Part 4
    Re #8: As the SMA system is an AC coupled (with various power sources all connected together into an AC mini-grid), we needed to size the load centre based on the worst-case sum of all of the planned power sources feeding into the load centre
    ...
    Inter-tie to second building (future) - 60 amp breaker

    This sums up to 225 amps, and we wanted to make sure we still had some headroom, so we ended up going with a 400 amp panel. It also gives us lots of room for current transformers for metering, shunt trip breakers, etc

    Did the inspector insist that you count the 60A inter-tie breaker as a source just because you might at some point put more RE tied directly to that building?
    If so, you can under the NEC only count the Amperage of the first breaker after the source (or for battery storage type 125% of the maximum continuous output rated by the manufacturer.)
    SMA SB 3000, old BP panels.
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    The second building will have another Sunny Island, which is capable of sourcing ("selling") up to 60 amps back into the mini-grid, so that's why they factored it into the calculations that way.

    The way it was explained to me is assume that there is a high impedance short on the end of the bus bar such that none of the breakers trip, but full current is being drawn. You need to look at every possible current source, figure out the maximum current that would flow before the breaker trips, and make sure that the bus bars would not be in an over current situation.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • raydiasraydias Solar Expert Posts: 68 ✭✭✭✭
    Re: Gulf Island Off-Grid System - Part 4

    Just curious but did you consider insulating the container and how will you deal with heat from the equipment (unless I missed it somewhere)? Might get a bit toasty in that metal container.
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    Re #12: We will be putting 2x4 walls (with insulation) around the container, and a green roof on top of the container. The location where the container will placed is shaded for most of the day, which also helps.

    We have already installed ventilation inlets and outlets for the batteries, and we will monitor the temperature inside each compartment.

    If we find that we need it, we'll add a temperature-controlled louvre and fan.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    More progress:

    attachment.php?attachmentid=5121

    All of the solar panels are now mounted on the array.


    attachment.php?attachmentid=5120

    The view under the array.

    We're planning to mount the inverters in a little shelter attached to the rear posts of the array.

    Here's the preliminary layout:

    attachment.php?attachmentid=5119

    We opted to install a load centre out at the array to allow us to add a second array in the future
    without having to bury a second teck cable run back to the container.

    Attachment not found. Attachment not found. Attachment not found.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • gww1gww1 Solar Expert Posts: 963 ✭✭
    Re: Gulf Island Off-Grid System - Part 4

    Thanks for the pictures, looks good.
    gww
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    More progress on the solar monitoring panel:

    attachment.php?attachmentid=5127

    On the outside-facing panel of the enclosure, we now have the power monitor mounted.

    attachment.php?attachmentid=5128

    Inside of the enclosure, everything is mounted, and we're starting to wire things up.

    Top left to right: PLC for system control, Ethernet switch, RS-485 power and power meter.
    Middle left to right: Contactors for isolating the inverters, power feed terminal blocks.
    Bottom left to right: Inverter A breaker, inverter B breaker, power meter breaker, power supply breakers, power supplies.

    Attachment not found. Attachment not found.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • NorthGuyNorthGuy Solar Expert Posts: 1,925 ✭✭
    Re: Gulf Island Off-Grid System - Part 4
    All of the solar panels are now mounted on the array.

    The array looks great.

    The soil seems to be so rocky. How did you manage to drill holes for the posts? How deep are they?

    If you ever get sub-freezing temperatures, I think it's a good idea to peel off the remnants of sono-tubes.

    There are so many boxes around Sunny Boys. Aren't they coupled to AC directly?
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: Gulf Island Off-Grid System - Part 4
    NorthGuy wrote: »
    There are so many boxes around Sunny Boys. Aren't they coupled to AC directly?

    That's a good point. The 3000TL's have 2 MPPT trackers each and place to connect 2 strings to each MPPT, so you shouldn't need combiner boxes between the pv and the sunnyboys.
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    Re #17: The array is located on a rocky outcropping. We drilled holes into the rock using a rock drill to insert rebar to stabilize the concrete posts. It was a lot of work, since the rock is fairly hard!

    That's good advice on the sonotubes. Moisture caught between them and the concrete could freeze, and cause cracking.

    Box "I" on the diagram is a string fuse. We've subsequently determined that we don't need this.

    Box "E" is the metering and control box that is shown in post #16.

    Re #18: We're only using a single 12 panel string per 3000TL.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    The batteries are now installed in the container:

    attachment.php?attachmentid=5149

    Attachment not found.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    More progress on the solar array:

    attachment.php?attachmentid=5241

    The plywood for mounting the inverters is now attached to the array superstructure, and a load centre is installed in a protective wooden box on the right.


    attachment.php?attachmentid=5242

    The anemometer for the Sunny SensorBox is installed in the centre of the array.


    attachment.php?attachmentid=5240

    A SensorBox (top left) is installed on each side of the array, and will measure panel and ambient temperature.


    Attachment not found. Attachment not found. Attachment not found.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • westbranchwestbranch Solar Expert Posts: 5,114 ✭✭✭✭
    Re: Gulf Island Off-Grid System - Part 4

    Dave I believe you mean the Combiner Box will be under the panels,
    your Load Center should be in the watertight container.
     
    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
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    Re #22 - No combiners on the system, as there is just two strings, one for each inverter.

    Our solar installer indicated that this isn't a problem as long as the load centre is sheltered from direct rain, and evidently it has passed inspection elsewhere in the area. I guess we'll find out during our inspection tomorrow.

    In other news, we've finished wiring up the control box, and completed preliminary testing. Next steps are to mount the box on the array, and program the PLC to connect the inverters based on the amount of sun hitting the array.

    Attachment not found.

    Power is on.


    Attachment not found.

    And, we now have power monitoring on the front panel.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • westbranchwestbranch Solar Expert Posts: 5,114 ✭✭✭✭
    Re: Gulf Island Off-Grid System - Part 4

    OK now I am confused as in post #7 you have a monster load center. Is there just a pair of CB's under the panel that can act as a PV disconnect?
     
    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
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    Re #24 - The load centre in post #7 is in the container with the batteries and Sunny Island inverters.

    However, we have another smaller load centre in a wooden box under the solar panels (first photo in post #21) in order to allow us to add a second array in the future without having to do another home run back to the container.

    Here's a photo showing the load centre under the solar panels, with the completed control box installed:

    attachment.php?attachmentid=5251

    Attachment not found.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: Gulf Island Off-Grid System - Part 4
    Next steps are to mount the box on the array, and program the PLC to connect the inverters based on the amount of sun hitting the array.

    All looks very professional and nicely done, congrats. Could you explain a bit more about the role of the PLC? Why wouldn't you just leave the inverters connected all the time?
  • solar_davesolar_dave Solar Expert Posts: 2,335 ✭✭✭✭
    Re: Gulf Island Off-Grid System - Part 4
    Re #24 - The load centre in post #7 is in the container with the batteries and Sunny Island inverters.

    However, we have another smaller load centre in a wooden box under the solar panels (first photo in post #21) in order to allow us to add a second array in the future without having to do another home run back to the container.

    Here's a photo showing the load centre under the solar panels, with the completed control box installed:

    attachment.php?attachmentid=5251

    Attachment not found.

    They do make outdoor load centers you might consider using one of those instead.
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    Re #26 - While the new SMA inverters are rated to have a very low current draw during periods of no sun, we have been advised that inverters in the past have consumed up to a quarter of a KWh per day, so we wanted to be able to automatically disconnect them during times when they will only draw power instead of supplying power. Once we have the system up and commissioned, we'll get some good data indicating how much current is drawn during no sun periods, and we can program everything accordingly.

    The PLC controls the two contactors, and communicates via RS-485 with the power meter and the Sunny SensorBoxes, which allows us to have it automatically disconnect the inverters when there is low or no light, and automatically reconnect when there will be sufficient light to generate power. It will also be hooked up to a web-based monitoring and control system that will allow for manual control and programming.

    Re #27 - I would have preferred one, but it turns out that outdoor load centres are not available in Canada, as they are not permitted by the electrical code here. Our electrician did a site visit today, and indicated that the weatherproofing that we've built is sufficient for the installed load centre, so we're good to go.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    The Sunny Boy inverters are now mounted. No nice bright red covers for us folks in North America... :(

    attachment.php?attachmentid=5410

    Attachment not found.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    Today was a big day — The container arrived on our property.

    The truck backs in:

    attachment.php?attachmentid=5432


    Lowering the container onto the foundation:

    attachment.php?attachmentid=5433


    All in place, and ready for wiring.

    attachment.php?attachmentid=5434


    We have plenty more work ahead of us, connecting everything up to the solar array, and
    finishing off all of the wiring, but things are getting closer and closer to being complete.


    Attachment not found. Attachment not found. Attachment not found.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
  • David and LauraDavid and Laura Solar Expert Posts: 139
    Re: Gulf Island Off-Grid System - Part 4

    The Teck cable is all installed along the walkway from the container to the solar array.

    attachment.php?attachmentid=5448

    attachment.php?attachmentid=5449

    As cost to excavate and enclose the cable in concrete to meet code turned out to be about the
    same to build a wooden protective structure, we ended up with a very nice little boardwalk
    through the woods.

    attachment.php?attachmentid=5450

    Attachment not found. Attachment not found. Attachment not found.
    House: 2x SMA SI 6048 w 24x 2V DEKA Unigy II; 2x SMA SB 3000TL-US w 24x Sharp ND-H235Q2
    Cabin: 1x Magnum MS4024 w 24x 2V DEKA Unigy II; 1x Morningstar TS-MPPT-60 w 6x Sharp ND-H235Q2; 1x 200 Watt Harris microhydro
    Intertie: 1x SMA WB 3800; 1x Lambda GEN-600 DC Supply; 2x PSL pQube
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