Final shopping list! - 48v off grid system

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Surfpath
Surfpath Solar Expert Posts: 463 ✭✭✭
in Off Grid Solar & Battery Systems #1
Thank you NAWS members for helping me with the design of my 48v 240v/50hz off grid PV/Hydro system. Special shout outs to Neil, Coot, Wayne, Vic, Vtmaps, and Icarus for their generous wisdom.

Since I live in a remote location where shipping takes time and you only want to go through customs once, I have taken my time to assemble each piece before it is all crated and shipped.

Apart from the batteries (another discussion), I am now at the stage where the smaller items on my “shopping list” need to be finalized.

Already purchased:
  • A FlexPower ONE-6 [this includes]: Prewired AC and DC boxes with 230VAC Bypass and Type F Outlet, 175ADC breaker, GFDI, 80 amp charge controller breaker, VFX3048E, MATE2, HUB4, RTS, FLEXmax 80, FLEXnet DC and surge protector for 230V 50Hz applications
  • Nine 220 watts PV panels (36.80VOC/29.76VMP) as described here:

Almost bought (batteries):
Also purchased:
A 48v micro hydro generator that will produce an estimated 1.8 Kwh/day (150w x 12 hours). Dump load controller & wiring to batteries already bought. Nothing else yet (eg. fuses or dump resistors). But unless someone has any immediate ideas I will leave this for another post.


Basic Wire Runs:
  • A 20 foot run from my combiner box to the battery controller.
  • A proposed four foot run from the controller to the battery bank.
Attachment not found.
Attachment not found.

Expected final shopping list:
Other items that have been recommended to me:
  • Battery cable to go between the batteries (seven lengths of 20 inch 2/0 Black Series Cable, 3/8 terminals)
  • Six feet of #2/0 GAUGE Multi Strand 105 Primary Cable (BLACK) and six feet of #2 GAUGE R Multi Strand 105 Primary Cable (RED) – aside: I presume this is to connect the controller to the batteries, since from the FP1-6 photo the unit comes with cable to go from the batteries to the inverter.
  • MagnaLug Cable Eye (what’s that?)
  • HEAT SHRINK 3/4" Heat Shrink (sounds OK).

Any other items for the list, ones to strike off/adjust, ideas or observations?
Thanks! -SP
Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #2
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    Re: Final shopping list! - 48v off grid system
    Surfpath wrote:
    A combiner box like the MNPV6
    Quite a lot of (say) 10AWG to connect the panels on the roof to the combiner box.

    Hi Surfpath,
    You can buy combiners with built in MC4 connectors:
    http://forum.solar-electric.com/showthread.php?16797

    Your panels should not be too far from the combiner box. Why do you need "quite a lot" of 10AWG? Are you planning to crimp your own MC4 connectors to the 10 AWG cable?

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Surfpath
    Surfpath Solar Expert Posts: 463 ✭✭✭
    #3
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    Re: Final shopping list! - 48v off grid system
    vtmaps wrote: »
    Hi Surfpath,
    You can buy combiners with built in MC4 connectors:
    http://forum.solar-electric.com/showthread.php?16797
    Your panels should not be too far from the combiner box. Why do you need "quite a lot" of 10AWG? Are you planning to crimp your own MC4 connectors to the 10 AWG cable?
    --vtMaps

    Thanks for the reply!
    My SPI panels come with Tyco connectors.
    Attachment not found.

    To go with the prewired MC4 box I'd have to cut off the Tyco connectors that come with the panels and attach on MC4 males ends.
    I just saw that midnite also sells a prewired combiner box that comes with tyco connectors: The MNPV4-TYCO. I don't see it on our host site though.

    You are probably right. I should not need a tom of cable for the panels. They should not be too far from the box.

    I should probably now research a wiring schematic. It'll help with this final order.

    Off the top of my head (warning: I am an electrical noob): I have 9 panels in total with 3 three panel series wired in parallel [I think I got that correct]. My intuition tells me that the positive of each panel in a series attaches to the negative of the one next to it. Where I may need some more cable (10 AWG?) is when the final positive and negative of each series needs to individually run back to the combiner box. For the series nearest to the combiner box this may not be a problem, perhaps the panel cables can reach by themselves. However, because the other 2 series will be located further away from the box, that's where I may need the 10AWG [plus a few more tyco connectors?]

    Is this gut instinct along the right path?
    Thanks!
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #4
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    Re: Final shopping list! - 48v off grid system
    Surfpath wrote: »
    Where I may need some more cable (10 AWG?) is when the final positive and negative of each series needs to individually run back to the combiner box. For the series nearest to the combiner box this may not be a problem, perhaps the panel cables can reach by themselves. However, because the other 2 series will be located further away from the box, that's where I may need the 10AWG [plus a few more tyco connectors?]

    Is this gut instinct along the right path?

    Yep, you're on track. Depending on how your panels are laid out you may also need different length cables for the positive and negative connections. For example, I also have series strings of 3 panels and they're laid out in a straight line away from the combiner. Since each panel is 1m wide, it means that the negative cable is 3m longer than the positive.
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  • Surfpath
    Surfpath Solar Expert Posts: 463 ✭✭✭
    #5
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    Re: Final shopping list! - 48v off grid system
    stephendv wrote: »
    Yep, you're on track. Depending on how your panels are laid out you may also need different length cables for the positive and negative connections. For example, I also have series strings of 3 panels and they're laid out in a straight line away from the combiner. Since each panel is 1m wide, it means that the negative cable is 3m longer than the positive.

    Got it. Your negative cable (on each series) is the cable furthest away from the combiner box.

    I now realize that there is probably an optimal configuration or two, that would simplify my wiring. I plan to now get up on the roof with a measuring tape and perhaps a couple of cardboard cutout "panels." Here are a couple of (not to scale) quick sketches of configurations that i'll try out:
    Attachment not found.Attachment not found.

    I see that my panel comes with cables that are 39" long. Hmm. That's not much. Looks like I will need a bunch of Tyco cable extensions for both the positive and negative series cables. Either that or figure how to splice these cables together (is this easy?). Good 10 awg is about $50-60 for a 100' reel. These connectors are quite $$.
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
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  • Surfpath
    Surfpath Solar Expert Posts: 463 ✭✭✭
    #6
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    Re: Final shopping list! - 48v off grid system

    Heyyy..what about this combiner box made by tyco......?

    [aside: I presume 'Solarlok' is just a brand name for Tyco connectors]

    SOLARLOK 5 string Combiner box

    And for a pretty awesome (for the solar industry) video:
    http://www.te.com/industry/solar/knowledgecenter/solarlok-combiner-box.aspx

    The pleasing thing is that the box is a little wider (11") than it is tall (6.6"). It may fit my proposed under eve installation area (see below) better than the taller Midnite products.
    Attachment not found..
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #7
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    Re: Final shopping list! - 48v off grid system
    Surfpath wrote: »
    Heyyy..what about this combiner box made by tyco......?
    If you need that form factor and don't mind fuses, it looks like a good option. Personally, I would prefer to have circuit breakers.

    The Midnite MC4 combiner box that NAWS carries also has fuses, but Midnite also builds them with circuit breakers (see that other thread I referred to earlier).

    Having circuit breakers means you can easily switch off strings of panels which is useful for diagnostic reasons. Some day you will wonder why you are getting only 80% of what you think you ought to get. Turn on the strings, one at a time, while reading the numbers on your controller. That will tell you if there is a string that is lagging.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Surfpath
    Surfpath Solar Expert Posts: 463 ✭✭✭
    #8
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    Re: Final shopping list! - 48v off grid system
    vtmaps wrote: »
    If you need that form factor and don't mind fuses, it looks like a good option. Personally, I would prefer to have circuit breakers.

    The Midnite MC4 combiner box that NAWS carries also has fuses, but Midnite also builds them with circuit breakers (see that other thread I referred to earlier).

    Having circuit breakers means you can easily switch off strings of panels which is useful for diagnostic reasons. Some day you will wonder why you are getting only 80% of what you think you ought to get. Turn on the strings, one at a time, while reading the numbers on your controller. That will tell you if there is a string that is lagging.

    --vtMaps

    Good advice Vtmaps. I can understand the pros and cons a bit better now. The fact that the Tyco box uses the same connectors as my panels, and that it looks to be the 'right' size for my installation, is appealing. However, I can appreciate what you say about using circuit breakers to test each string. Then again (this is the newbie in me speaking), using the tyco connectors on the underside of the tyco control box (and a panel array disconnect) could you not unplug/plug one string at a time to see the output at the controller? Or is this a big no-no, given the voltages at hand.

    Talking about a panel array disconnect, I'm wondering if this is another thing for my shopping list (I'll have to check and see if the Flexmax 1 already includes this).
    Thanks for the help.
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #9
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    Re: Final shopping list! - 48v off grid system
    Surfpath wrote: »
    Good advice Vic. I can understand the pros and cons a bit better now. The fact that the Tyco box uses the same connectors as my panels, and that it looks to be the 'right' size for my installation, is appealing. However, I can appreciate what you say about using circuit breakers to test each string. Then again (this is the newbie in me speaking), using the tyco connectors on the underside of the tyco control box (and a panel array disconnect) could you not unplug/plug one string at a time to see the output at the controller? Or is this a big no-no, given the voltages at hand.

    Talking about a panel array disconnect, I'm wondering if this is another thing for my shopping list (I'll have to check and see if the Flexmax 1 already includes this).
    Thanks for the help.

    The problem is not the voltage by itself, but the fact that these (and most if not all other connectors) are not designed to interrupt DC. That is, they are not intended to be unplugged under load. The risk is that the arc as the contacts separate may damage the contact surface and make them less reliable for reconnecting. If you have a higher string voltage, that makes the arcing concerns greater.
    When you look at interrupting a fault current, such as a short circuit on the battery, the ability to interrupt a DC arc actually becomes critical, in that some fuses or circuit breakers are designed to rely on the fact that the AC current passes through zero twice per cycle, making it easier to extinguish the arc.
    In the case of a connector handling only the limited current available from one string of panels, this is not really an issue, but the potential damage to the contact surfaces is.
    SMA SB 3000, old BP panels.
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  • Surfpath
    Surfpath Solar Expert Posts: 463 ✭✭✭
    #10
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    Re: Final shopping list! - 48v off grid system

    Thanks for the heads up inetdog. That, and the ability to test panel strings individually, convinces me that a prewired panel containing safe touch 150v breakers is now the way to go (such as the MNPV4-MC4 from NAWS).

    Seeing that MC4 connectors and leads are far more available and generally less expensive than their Tyco counterparts I am also thinking of changing some of my panel's Tyco connectors to MC4's.

    Ie. just those that need to run to the combiner box. I can keep the Tycos that go inbetween the panels in series. Sound right?

    I looked up a few youtube videos and it appears that crimping on MC4 connectors is not too complex. There are convenient specially built (& expensive) MC4 crimping tools, however it appears that, if you are diligent, you can make fine sturdy connections using a basic MC4 wire crimper.

    I know the OP is rather long, but I encourage folks to quickly review it. I am still open to suggestions & ideas for my final shopping list. Anything goes!
    -SP
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #11
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    Re: Final shopping list! - 48v off grid system
    Surfpath wrote: »
    Seeing that MC4 connectors and leads are far more available and generally less expensive than their Tyco counterparts I am also thinking of changing some of my panel's Tyco connectors to MC4's.

    Ie. just those that need to run to the combiner box. I can keep the Tycos that go inbetween the panels in series. Sound right?

    Yes, there would not be any problem with using different connectors within the string than at the ends of the string, although it would reduce your ability to re-patch the panels if you are testing/troubleshooting.
    If you are concerned about the warranty on the panels, you will want to make the run from the end panels to the combiner box using an extender cable with Tyco on one end and MC4 on the other rather than replacing connectors on the panel leads.
    SMA SB 3000, old BP panels.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,467 admin
    #12
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    Re: Final shopping list! - 48v off grid system

    Just to be clear:
    safe touch 150v breakers

    There are, as far as I know (which is not very far :blush:), only "touch safe" fuse holders--The term does not apply to breakers.

    From your combiner link:
    The MNPV4-MC4 is a pre-wired PV combiner box with MC4 connectors installed for easy and fast installation. It's the same enclosure as the MNPV6 but it also includes the four touch safe fuse holders, four male and four female MC4 connectors and internal wiring as seen in the picture. It's rated NEMA 3R for outdoor locations which means it's 100% weatherproof when installed according to the manufacturer's instructions. The touch safe fuse holders allow the unit to be used with voltages as high as 600 VDC. This unit is rated for maximum of 80 amps. Four 15 amp fuses are included. If you want extra fuses, you can find them here.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #13
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    Re: Final shopping list! - 48v off grid system
    BB. wrote: »
    Just to be clear:

    There are, as far as I know (which is not very far :blush:), only "touch safe" fuse holders--The term does not apply to breakers.


    -Bill

    Meaning, I presume, that although the fuses are rated to safely interrupt DC in a fault condition, pulling a fuse under load is not supported? By contrast, a breaker which interrupts DC can also be used as a switch.
    SMA SB 3000, old BP panels.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,467 admin
    #14
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    Re: Final shopping list! - 48v off grid system

    I think it means that you can safely touch/remove a fuse with power applied (insulated fuse holder).

    You cannot, pop the fuse holder open when under load (it could arc and damage/ruin the fuse holder assembly and even catch the holder on fire).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #15
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    Re: Final shopping list! - 48v off grid system
    Surfpath wrote: »
    a prewired panel containing safe touch 150v breakers is now the way to go (such as the MNPV4-MC4 from NAWS).

    As BB. has mentioned, those are fuses, not circuit breakers. Midnite will build the same boxes with real circuit breakers, however NAWS does not show that configuration in their online store.

    Ryan 'halfcrazy' from Midnite recently posted about this (post #6 in this thread):
    http://forum.solar-electric.com/showthread.php?16797

    --vtMaps

    Edit: By the way, those fuse holders take up more space on the rails than real circuit breakers. That means that the MNPV6 box can hold 6 breakers, but only 4 fuses.
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • TheBackRoads
    TheBackRoads Solar Expert Posts: 274 ✭✭
    #16
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    Re: Final shopping list! - 48v off grid system

    I love that box, it's so easy to use. I can take more pictures of it if requested!
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  • Surfpath
    Surfpath Solar Expert Posts: 463 ✭✭✭
    #17
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    Re: Final shopping list! - 48v off grid system
    TheBackRoads wrote: »
    I love that box, it's so easy to use. I can take more pictures of it if requested!

    You're the man. That would be great. I believe I have seen a few of your photos already. I think yours is the roof top 2 string installation where you took one of the empty pairs of connectors on the bottom of the box and used them to connect your wire run to your controller inside (I think I got that right). Quote: "I used an open string to connect an existing MC4 cable (furthest right) to my inside connection."

    I'd be nice to see how you wired this last feature. You had a photo of your new opened box, but I think this was before you finished your connections. An open box post connection shot or two would be nice.
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
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  • TheBackRoads
    TheBackRoads Solar Expert Posts: 274 ✭✭
    #18
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    Re: Final shopping list! - 48v off grid system

    Sorry for the delay, been stuck on a new forum about snow guns (to make snow). I'll snag those tomorrow and post. Basically its all connected internally to a bus. 2 strings connect and I'm using 1 of the 4 (2 open) string connectors to an MC4 cable to my charge controller. Sure, I could blow the fuse feeding the current back in but according to my CC it's not likely to be an issue.

    Browse these, might help.
    http://jefftheman.net/Pics/Solar/8.11.12/
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #19
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    Re: Final shopping list! - 48v off grid system

    Just an observation, you might consider placing a non conductive plate between the terminals of those 2 batteries or flip one around... safety first, it easy to have an accidental short with the existing orientation.

    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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