Author Topic: Aloha From Hawaii - needing help.  (Read 1007 times)

tradewinds

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Aloha From Hawaii - needing help.
« on: November 02, 2013, 03:03:43 AM »
Where to start?
      I've been living off-grid for 4 years now with a Xantrex XW4548 Inverter, Outback FM80 charge controller, 720ah 48v L-16 battery bank and only using 12 of my 20 Canadian Solar 235W panels in a near level orientation atop a 20í shipping container (this was a temporary situation that has been ignored too long and doesnít even achieve our possible daily averaged  4.6 insolation hours with a fixed and properly angled array). I added a 17cf Chest Freezer to my load a couple months ago and tipped my demand over my current arrays setup ability during our ďfall/winter seasonĒ (By Hawaii standards).
My plan has always been to use all 20 panels on a tracking system.

Hereís my background with regard to anything perhaps relevant to this subject.
Computer programming back in the early 80ís-90ís then stopped altogether with the exception of some HTML code and other minor stuff where nearly all my recollection is EXTREMELY limited thereto today.
General electronics from again the Early 80ís-late 90ís with very limited digital experience/study, with a majority of designs that revolved around analogue circuitry only and extreme HV experimentation (physics related study).
General metal fabrication, welding etc.

Iím located at latitude 18+ (Southern Hawaii) which tosses a monkey wrench into using a linear actuator for an optimal vertical axis (east/west) drive so Iíve already taken the liberty in purchasing a slewing drive for that aspect of the build.  It has a  61:1 ratio with a ĺĒ diameter 3/16 keyed hole input, it's a fairly heavy duty drive but we get really heavy winds here (about 3k' from the Pacific Ocean 120' elevation) so the frame needs to be heavy duty as will it's drive components.
Iíve already determined Iíd rather not use a light chasing controller but I am lost when it comes to the programming, digital circuits, stepper motors, etc.

So... here I am, looking for help/advice.
Thanks,
 Mike.


tradewinds

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Re: Aloha From Hawaii - needing help.
« Reply #1 on: November 02, 2013, 12:12:10 PM »
I recall reading about the Arduino several years back when the boards became available. I believe it was addressed in another article I was reading about some other device which was being controlled by the Arduino.
Rusty would be a great description as to my skills revolving around this subject. Hereís my intent and please correct me if Iím wrong within the following with regard to any assumptions in execution of those intents.
What I am hoping to build here is a Digital Heliostat. The brain of the system will consist of an Arduino microprocessor. The Arduino will ultimately control 2 stepper motors bridged through a stepper control board and receive input from other sources such as an anemometer to provide real-time information regarding wind velocity for putting the array into protection mode accompanied by a wind direction meter to provide for minimal array profile adjustment to that of the oncoming storm winds. Iíd also like it to have the ability to determine the radiant level and switch from a standard precise pointing routine to that of a power saving pointing routine consisting of longer durations between adjustments. If thatís not enough, Iíd also like to incorporate a remote to control the arrays position manually for servicing, etc.
What would be the recommended components to get started in making the above happen?  IeÖ which Arduino board, applicable stepper controllers, etc. Any recommended programs to get things rolling? Iím flexible between Linux and Windows (I donít use MACs anymore).
Thanks,
Mike



Gabriel

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Re: Aloha From Hawaii - needing help.
« Reply #2 on: November 02, 2013, 07:14:05 PM »
Hi Mike, and welcome to the forums!

Actually, for anyone reading this, linear actuators tend to be bad for sun tracking no matter what your latitude (at least for dual axis trackers, or trackers that need to maximize output through the summer months too).

It sounds like you should be able to use the Arduino program and electronics featured on the main [url = http://cerebralmeltdown.com/Sun_Tracking_and_Heliostats/]Open Sun Harvesting Project[/url]  page to get you off to a good start. There's a lot to read there, but it should answer most of your questions.  You might also take a look at [url = http://www.cerebralmeltdown.com/2011/07/19/sids-solar-panel-sun-tracking-machine/]Sid's machine[/url] for an example of a beefier circuit / machine.

I have no experience with interfacing any type of wind measurement device with an Arduino, but there are probably examples out there somewhere on the net.
I also haven't tried interfacing any devices that directly measure the amount of energy available from the sun. I know there is a device called a Pyranometer that will accurately measure it, but that might be overkill for this. I $2.00 photoresistor might do the job just fine.
In either case, I would probably get the basic tracking down first, and then try adding on the extras.

Let me know if you need any clarification on anything. I'll help where I can.
Gabriel