Alternative for Unistrut for creating DIY solar panel rack?

PorkChopsMmm
PorkChopsMmm Solar Expert Posts: 189 ✭✭✭✭✭
in PV Installers Forum - NEC, Wiring, Installation #1
I am putting together my own solar pole mount as others have done on this forum. I am trying to figure out how to rack it and I have seen many use Unistrut. I need 8 pieces 16' long, and since I have only found pieces in increments of 10' near me (so either 10' or 20') it looks like I will need to purchase 20 footers. These are somewhat hard to source near me and I have been quoted prices anywhere from $27 a stick for narrow channel to $88 a stick for deep channel, all 1 5/8" x 1 5/8" plain finish.

Can you all recommend any other material for the racking? Lower cost is my goal as well as strength -- the Unistrut seems like the cheapest/strongest solution. Is there anything else I should be considering?

Thanks!
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #2
    Re: Alternative for Unistrut for creating DIY solar panel rack?

    Hi P C M,

    Cannot tell just where you are located. Perhaps you are in the USA. If you wish to use XxxStrut material, suggest that you try a commercial/wholesale Electrical Supplier. Many usually have XxxStrut in 20 foot lengths in the standard Zinc finish.

    Others here have suggested finding a commercial Aluminum supply vendor. Most stock a number of different profiles in different thicknesses and in 20-foot lengths.

    Either of these approaches, or yet others require some attention engineering the solution to be adequate for your situation. This engineering component is one of the main reasons that commercial racks (usually expensive) are often used, as opposed to home-brewing your own. And, generally, if the installation will be inspected, a home brew solution would need a PE signoff on structural soundness. etc.

    Have used Strut material for racks in the past, and it does work well, and is not too expensive. YMMV, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • PorkChopsMmm
    PorkChopsMmm Solar Expert Posts: 189 ✭✭✭✭✭
    #3
    Re: Alternative for Unistrut for creating DIY solar panel rack?

    Thanks for the info. Sorry, I am in Zone 5 Michigan. I found a local electrical place that charges $2.31 per ft for the plain Unistrut deep channel. So each 20 ft piece is $46.20. That's better than a local Fastenal outlet which quoted me $88 per 20 ft section. I need 8 sticks so it is getting expensive.

    I will post a build thread when I get done -- I think you all will be satisfied with how it is built. Thanks for the heads up on the aluminum vendor -- didn't think of that. I will see if they can provide what I am looking for.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #4
    Re: Alternative for Unistrut for creating DIY solar panel rack?

    OK P C M,

    Glad you found a solution. All of this stuff is expensive, and seems to get evermore so, but am sure that you will do a very good job, and the racks will last many decades Will look for your as-built post later. Thanks for the info on your location. Have Fun, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    #5
    Re: Alternative for Unistrut for creating DIY solar panel rack?

    Don't know exactly what you are planning, but a pole mounted rack that is 16' wide or long is going to need something stronger than Unistrut. The last engineered pole mount we did this big was constructed with 2" x 6" heavy gauge structural aluminum sq tube. Ya, the underdesigned rack will go for a long time, but then that big wind storm will come along when you least suspect it and your precious array will be little pieces of glass and silicon.
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  • sunbunny
    sunbunny Solar Expert Posts: 59 ✭✭✭✭
    #6
    Re: Alternative for Unistrut for creating DIY solar panel rack?

    I just got the aluminum for my rack. 2"x2" x 1/4" thick angle. 25' long. $3.00 a pound or $84 for each length.
    The $3.00 a pound was for any dimension/thickness of angle but the price goes up for T shape ($4).
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  • rgk1
    rgk1 Solar Expert Posts: 135 ✭✭✭
    #7
    Re: Alternative for Unistrut for creating DIY solar panel rack?

    I tend to agree that strong aluminum tube may be a better choice. I have a very small 4 panel array using Unistrut. I did use the shallow channel thinking the deep channel was overkill. After it was all up and quite surprised at the weight of the entire thing, there is some flex to it. Not sure if it will be a problem when one of those 60-70mph thunderstorm outflow winds hit it. Time will tell.

    There are a couple of pics in my photo album if you want to see how I did mine.
    4-Risen 320 watt in series/parallel, 8-215ah 6 volt GC2 batteries in series, Exeltech 1100 watt/48 volt inverter, Tristar 45 MPPT controller.
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  • PorkChopsMmm
    PorkChopsMmm Solar Expert Posts: 189 ✭✭✭✭✭
    #8
    Re: Alternative for Unistrut for creating DIY solar panel rack?

    Thanks guys. I haven't seen the recent posts. I did go with the deep channel Unistrut. I will post a build thread when I am done, which will hopefully be in a week or so.
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