tracker verses roof mount

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Re: tracker verses roof mount

Postby treechange » Sat Apr 19, 2014 11:00 am

Bthree wrote:
Why bother with trackers unless you want a technical challenge


I suppose I am looking for projects to do, once I have built the house, I will need something to occupy my time.

Besides a technical challenge might be good for me.

Again I am looking for efficiency, I suppose I would get a kick out seeing how much energy I could produce from a small amout of panels, rather than putting them on the roof and forgetting about them.

But I will admit I don't have any experience in this, and I don't know much about it as well, just what I have read.

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Re: tracker verses roof mount

Postby Warpspeed » Sat Apr 19, 2014 1:58 pm

There are a few things to think about.....

A tracker is only going to provide about an extra 25% to 30% extra power, but it will produce a much flatter power curve.
Commercial trackers seem to me to be either pretty cheap and nasty, or outrageously expensive for what you get.
But if you can build all the tracking hardware and electronics yourself, may still be an option well worth consideration in my opinion.

Installing more than one tracker can be problematic, because at low sun angles, one tracker with panels tilted almost vertical can shade the other tracker, so they cannot be located too close together.
Low sun angle shading is also often a problem in the suburbs, with neighbours roof tops, trees, fences and so on.

But there are some advantages too.
At very low sun angles, at least half the almost vertical panels on a tracker will be sticking straight up high into the air, and the upper group of panels might be able to see over some shading obstacles.

It has been argued that multiple strings of fixed panels facing in different directions, with their own independent MPPT controllers might be more cost effective, and require less maintenance.
That particular argument is much debated, but has yet to be conclusively proven either way.

I am very slowly putting together a two axis tracker for similar reasons.
As a pretty interesting technical challenge, and something to do in retirement.
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Re: tracker verses roof mount

Postby treechange » Sat Apr 19, 2014 3:02 pm

Although I am a builder, I don't think it is past my expertise level to build a tracker.

and I will definitely have the time, but if the nett value of the project is not so great, maybe I am better spending my time elsewhere.

Not sure what way to go, and the seems to no clear advantage or even opinions on it. :(
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Re: tracker verses roof mount

Postby Warpspeed » Sat Apr 19, 2014 3:07 pm

Different people are trying to achieve some quite different things, so there is hardly likely to be a unanimous opinion on how best to go about all this.
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Re: tracker verses roof mount

Postby treechange » Sun Apr 20, 2014 8:36 am

True enough Warspeed, All roads lead to Rome, as they say.

Thanks for your thoughts.

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Re: tracker verses roof mount

Postby Whitespeed » Sun Apr 20, 2014 9:15 am

[quote="treechange"] "the seems to no clear advantage or even opinions on it"

Most opinions on this subject appear to be; If you have a large back yard with minimum shading, and the inclination and skills to build your own tracker, then it might be viable, however as Gordon has said, a multi aspect virtual tracker, on a ground mount, might be a better option.

Because its on the ground you might engineer your mounts to be seasonably adjustable further increasing gains.

Myself, I have what they have described as a virtual tracker. My panels are mounted on a shed roof with 22 degree roof slopes to the east and west. I then have the back row of panels on 45 degree tilts to the north and the row in front flat on the roof.

After much playing around this gives me a good spread of power, panels that don't look to shabby as they are all mounted together without being spread all over the roof. And an acceptable compromise between summer and winter sun angles with no shading as only the back set on each roof plane are tilted.

As warpspeed has said, different people, different objectives :)
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Re: tracker verses roof mount

Postby treechange » Sun Apr 20, 2014 11:56 am

Thanks for your description of your solution Whitespeed.

I have plenty of room to play with, so I will be including some form of ground mount panels, how much I don't know though

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Re: tracker verses roof mount

Postby Tracker » Mon Apr 21, 2014 10:50 am

Whitespeed wrote:....As warpspeed has said, different people, different objectives :)


The thing that I have not picked up on is te background to the tracker project.. Is this for OFF-GRID, or Hybrid power or what...

My tuppence worth, Just add 30% more panels, and then get stuck into Hyproponics/Aquaculture..

Now that will give you years of practical pleasure from growing the freshest of vegies and the best of fish..
..
.
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Re: tracker verses roof mount

Postby treechange » Mon Apr 21, 2014 2:37 pm

[/quote]

The thing that I have not picked up on is te background to the tracker project.. Is this for OFF-GRID, or Hybrid power or what...

My tuppence worth, Just add 30% more panels, and then get stuck into Hyproponics/Aquaculture..

Now that will give you years of practical pleasure from growing the freshest of vegies and the best of fish..
..
.[/quote]

Hi Tracker, it will be at least hybrid to start with, I need to get some confidence that we could go off grid and still keep our lifestyle we want. The 22kw air cond is the biggest power user, followed by the pool pump, and the some power tools. I have been looking at batteries, but the 2000, or 3000ah batteries are looking like what I will need.....................not that I know anything about it. just in my own mind.

I will for sure get into growing veggies and the like, and would in my heart like to be off grid as well, my take a while to get there.
I still like the idea of a steam generator, but adding more panel could be a better option. endless hot water for heating in the winter sound ok, but there are always wetback stoves and wood heaters for that.

there is a lot to think about, as well as built the house, get the grounds in order.................... heeeeeelllllpppp lol

Nig
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Re: tracker verses roof mount

Postby Tracker » Mon Apr 21, 2014 4:17 pm

..
You will see a thread on "Modifying a W7"..
That is what Keen Is... :mrgreen:

The simple reality is that Off-Grid power is a life time consideration, and IF you really want a set and forget system, then you could be better aiming for a complete package (turn key) system.. eg.. Positronic Solar..

Trackers are devices that will likely need a deal of intervention with , to keep operating properly.
I have seen a few farms, where the tracker stopped for the LAST time and now just points NORTH.. :cry:

and where are you
..
.
Retired Engineer and keen PV experimenter - Always ready to learn and share.
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1.7kW First Solar/Outback Island circuit - Peak Replacement Power
Governments won't save the world :-) They will just TAX it :-(
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