Combiner Box Inside.. or out near panels.???

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ywhic
ywhic Solar Expert Posts: 621 ✭✭
in Off Grid Solar & Battery Systems #1
My 'combiner box' can take upto 1 AWG wire to the main lugs.. the MorningStar TS45 controller can take upto 2AWG..

For distance of say 12 feet one way on 2AWG .. I'd lose 1.28% off the 40 amps max I'd be bringing in...

Wondering if that would be better than the 10AWG going the same distance (8amps) at 1.64% per lead if the combiner box was inside as originally intended??

Granted I may loose some as the 3' lead on the panels would need a small extention for each of the 5 panels..

I'm sure the TS-45 controller has to be inside some cover as well.. so leaving that outside isn't an option..

I could put both the Combiner Box & Controller in 1 hanging poly lock box.. but the lack of air I think would kill it.. (in TX)..

Suggestions for an outdoor 'box' ??

30' of MC4 wire is $30 currently (with ends on).. that would be upto 15' in one direction.. I would need 5 (for the 5 panels).. ($150.)

24' of 2 AWG wire is like $50..

15' of MC4 wire is $20 currently (with ends on).. that would be the size I would need to buy to get 3 panels to the combiner if outside.. ($60)

15' of MC4 wire is $16 currently (with ends on).. that would be the size I would need to buy to get 2 panels to the combiner if outside.. ($32)

Looks almost like a break even unless someone can give me ideas..

I do have the remote meter for the TS45 controller.. with 90' of cable for that..
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #2
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    Re: Combiner Box Inside.. or out near panels.???

    just a thought, but you can buy the blank MC4 connectors and a spool of wire, and make your own custom length cables. I did that with my setup and it's worked out pretty well.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
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    Re: Combiner Box Inside.. or out near panels.???

    this is on the tristar instructions.

    Mount the TriStar MPPT indoors. Prevent exposure to the elements and do not allow water
    to enter the controller.

    indoors to me states someplace that a human being can enter and move about in like a home, but a shed i would ask them if it would suffice as my guess is it would be fine. an enclosed box imo does not meet their requirements in keeping with the warranty. to not follow this means the warranty is violated and you'd be on your own if something would happen. an enclosure outside would be too confining and would get to be very high temps at times and that would kill the cc.

    now they further mention this,

    If required, the controller may be installed in a ventilated enclosure with sufficient air flow.

    i don't think it would be possible for enough air to pass in most small enclosures, even if vented, in areas that receive temps over 100 degrees not that in the 90s is much better. you would need morningstar to be more specific on the minimum size a box would need to be and how to properly ventilate. they should be able to site examples of what you can get for your application.

    me, i'd put it indoors closer to the batteries.
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  • ywhic
    ywhic Solar Expert Posts: 621 ✭✭
    #4
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    Re: Combiner Box Inside.. or out near panels.???
    Dill wrote: »
    just a thought, but you can buy the blank MC4 connectors and a spool of wire, and make your own custom length cables. I did that with my setup and it's worked out pretty well.

    Um.. I thought you needed a special crimper??? if not I'm in for that idea..
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #5
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    Re: Combiner Box Inside.. or out near panels.???
    ywhic wrote: »
    Um.. I thought you needed a special crimper??? if not I'm in for that idea..


    the ones I purchased just had a standard crimp end. I crimped and lightly soldered them to ensure they held firm. Just make sure you use UV resistant wire.
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  • ywhic
    ywhic Solar Expert Posts: 621 ✭✭
    #6
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    Re: Combiner Box Inside.. or out near panels.???

    I found these for like $2/each.. says for 10 wire.. :roll:

    MC4.JPG

    Looks like a crimp/solder to me..
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  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    #7
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    Re: Combiner Box Inside.. or out near panels.???

    those look real similar to what I used. I'm anal about wire runs being the correct length, so they were a godsend for being able to custom size all my runs.
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  • CATraveler
    CATraveler Solar Expert Posts: 98 ✭✭✭✭
    #8
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    Re: Combiner Box Inside.. or out near panels.???

    Can you run conduit and use non UV wire? You'll still need the MC4 connectors but could save on the wire.

    Also look at using 2-4ga wire to the combiner reducing at each end perhaps by not putting all of the wire strands in the connector. That will reduce the wire resistance.
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