Tracking question

Frxddy
Frxddy Solar Expert Posts: 113 ✭✭✭✭
in General Solar Power Topics #1
I have four 230 watt panels that I plan on putting on a tower and one way or another, make them track the sun. I will manually change the angle for the seasons. I have looked into a few different ideas for home made tracking. I mentioned to my wife that returning from sunset position to point toward sunrise was "the trick". She came up with one I hadn't thought of and I'd like opinions, or knowledge of why it wouldn't work. She said "Why not just make it a giant clock and let it make a complete revolution once a day?" First reaction is "twisted wires", but, it happens that I have a 30 amp slip ring assembly on this tower already. It's made for 240 volts and I am using Enphase inverters so it should do the job. But... is there something I'm missing?
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #2
    Re: Tracking question
    Frxddy wrote: »
    I have four 230 watt panels that I plan on putting on a tower and one way or another, make them track the sun. I will manually change the angle for the seasons. I have looked into a few different ideas for home made tracking. I mentioned to my wife that returning from sunset position to point toward sunrise was "the trick". She came up with one I hadn't thought of and I'd like opinions, or knowledge of why it wouldn't work. She said "Why not just make it a giant clock and let it make a complete revolution once a day?" First reaction is "twisted wires", but, it happens that I have a 30 amp slip ring assembly on this tower already. It's made for 240 volts and I am using Enphase inverters so it should do the job. But... is there something I'm missing?

    IMO, unless your wires are very stiff or short, you'd be better off with good, solid connections. One idea, get your hands on one of those big old satellite dish assy's that used a motor to track from sat to sat, replace whatever remains of the big dish with your panel mount, have it move, clock-like across the sky, starting when light sensors detect the arrival of morning, then reset to the morning position when it becomes dark again. A dual timer could be used (one possibility). one to start the motor once every hour for example, and the second timer could dictate how long the motor ran each time. Should work great until the first total solar eclipse. :p
    Better still, check into what tracking system the commercial trackers use and go from there. Someone on here should know the system they use.
    Good luck
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
    Re: Tracking question

    I've moved this thread because it has the potential for broader appeal than just grid-tie. ;)

    As for using a slip-ring, forget about it. Troublesome things they can be.
    So here's an alternate idea in keeping with the original "clock" scheme:
    Ever seen the mechanism on an oscillating fan?
    The motor runs in one direction, but the crank causes it to reverse the the lateral direction of motion.
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,891 ✭✭✭✭✭✭
    #4
    Re: Tracking question

    The three big ones! Wind, Snow & Building codes
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • Frxddy
    Frxddy Solar Expert Posts: 113 ✭✭✭✭
    #5
    Re: Tracking question

    Thanks for the input. This is going to be next years "hobby project". For now I have mounted those four panels on the garage roof.

    Troubles with slip ring assemblies? It's the one thing on the windmill that was trouble free. Maybe cheap ones are problems? I don't know, but this seems built like a tank & even has replaceable carbon brushes. If I decide to use it, I don't think 800 watts are going to be much load on a 30 amp device.
    I like the oscillating fan idea. I'm not sure how many degrees of swing that design will do, but I'll check into it.
    The wind load will be much, much less than my turbine was. As long as I build the racks strong enough, the tower will take the stress. Snow? Happens every year! The winter angle of the panels won't hold much, if any. Permits are no problem. I have all permissions needed already. I am fortunate to be "out in the country".
    I do have a 5 foot long ball screw, extra heavy duty. Maybe I'll try to put that into service. So many different directions one can take. Hmmmmm.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
    Re: Tracking question

    Sounds like your slip ring is of the type used on silo unloaders (handling 5-7 HP 240 VAC motors). If you're not going high Voltage DC it could work. What were the specs on the windmill's gen?

    You could use the lead screw. You could get even "screwier" and have a reversing switch to change the motor direction at the end of the day. Go bananas! Add a speed changing switch and time setting so it goes back quickly! Wouldn't that be something to watch? The day is done: Click. Whir. Panels reset, waiting for dawn. Rise in PV Voltage triggers tracking mechanism. Optical differentiation feeds microprocessor data to keep panels constantly in-line with sun by varying motor speed.

    Oh wait, the idea was to Keep It Simple, Stupid. :p
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  • Frxddy
    Frxddy Solar Expert Posts: 113 ✭✭✭✭
    #7
    Re: Tracking question

    Heeheee! I like the quick return idea. Hmmmm..... my garage door opener is a double speed one, but it does not jerk start or stop. It ramps up to speed over the first 4", then ramps down the last 4".

    The slip rings will not be DC. Using the Enphase micro inverters makes it so the slip rings will see 240V AC. I can surely understand that DC and slip rings might be a recipe for bad arcing.

    No need to keep it simple.... these four panels are the "hobby" panels. I don't understand deep electronics, but I follow directions with the best of 'em!

    This is going to be next season's project. I put these 4 on the garage roof for now. Next spring I'll get to building this rig.

    Thanks for any and all input. If I use your idea I'll name it after you. ;)
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #8
    Re: Tracking question

    Got to do the legal thing and point out the possible trouble with getting G-T approval for this set up. You just never know what AHJ's will object too. If they haven't seen such a set-up before, they like to say "no" just to make sure they're not held responsible should anything go wrong.

    Hmm. "The Cariboocoot Rube Goldburgian Way Too Complicated Tracker". Probably have to shorted it to something like "That Thing That Quit Working After Three Days". :p
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,891 ✭✭✭✭✭✭
    #9
    Re: Tracking question

    Add to Coot with the other issue of Homeowners insurance specifically if there is a fire. A very nice weasel clause that the insurance can use is something like this.
    If it does not look and feel professional you could be exposed.

    Do it, have fun, I am doing my 11th tracker tonight, after the day job!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • TnAndy
    TnAndy Solar Expert Posts: 249 ✭✭
    #10
    Re: Tracking question

    I don't know about the slip ring thing, never having used one.

    I used 36" linear actuators like they used on the old C band satellite dishes to power my home made trackers. The drive controller is made by the Analoguy out of Vancover, BC.

    I've had the original two arrays up for almost 3 years ( expanding from 6 panels on each to 10 now ), and am just finishing up another 10 panel (245w size) now, and this one will be auto drive in the east/west axis, and have a manual button for the seasonal axis ( 24" actuator )
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #11
    Re: Tracking question

    TnANdy, do you have a web address for the Analoguy? tried a Google search but only got some guy in Vancouver Washington.

    thanks
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
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    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #12
    Re: Tracking question

    WB,

    Try this:

    http://www.theanalogguy.com/

    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 ✭✭
    #13
    Re: Tracking question

    I've wondered about using a slanted array on a turntable that rotates about the vertical axis. Let it rotate just like a clock (using military time)- faces east in morning, south at noon, west in evening. The angles wouldn't be as perfect as in a conventional tracker, but close enough, and a lot simpler. Still have the wiring problem of course. Could let it just wind up , then manually unplug it and unwind it every week. Or use a reversing gearmotor to drive the turntable with limit switches like a rainbird.
    Bottom line is that tracking systems don't make sense anymore with the drop in PV module prices and besides - they are ugly to everyone else except us gadget freaks.
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  • TnAndy
    TnAndy Solar Expert Posts: 249 ✭✭
    #14
    Re: Tracking question
    solarix wrote: »
    Bottom line is that tracking systems don't make sense anymore with the drop in PV module prices and besides - they are ugly to everyone else except us gadget freaks.


    ahahahaaaaaa.....I hear ya. Funny thing though, when folks come to look at mine, and the motors suddenly "jog" a little for sun correction, (about every 10-15min) they have this look of surprise and say "Do those things MOVE ?"

    I had to pole mount mine anyway, due to a lot of tree shade on my roof I wasn't willing to part with, so the step to making them track was only a few bucks more for the amount of extra power return.....and the COOLness factor, as I am a self confessed gadget freak.....ahahahaaaa......but yeah, for most folks, I'd agree......add more panels and forget tracking.
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  • rplarry
    rplarry Solar Expert Posts: 203 ✭✭
    #15
    Re: Tracking question

    I built my first trackers about 6 years ago. It is a really fun project. I enjoy fabricating stuff. If you don't enjoy fabrication then this is not a project for you.
    I used the redrock solar sensor. You can get them here: http://www.redrok.com/electron.htm#led3x
    I use the sensor with the anti reverse circuit, if you use the other without the anti reverse, then the motor will hunt for the sun unnecssarily for the 1 second that it runs.
    The sensor will track the sun all day and after the sun goes down it will reset the array to the east and be ready for sun rise.

    The next piece of hard ware you will need to buy is an actuator motor. I bought several of the cheap one over the years, off of ebay and they are made in china and fail pretty quickly. The ones that I found that hold up you can get here: http://www.primefocusantenna.com/index.php
    Get the good ball screw one. They are more expensive but they are bullet proof.
    Depending on the square footage of your array you can use (as was suggested in another post) an old large dish sattelite dish mount. But for larger arrays I would suggest making your own and using
    1.5" to 2" pillow block bearings for the pivot points.
    Good luck with your project, it should be fun.
    Larry
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