Alternative Technology Assn Forums

1. 

   ben76da
   Member

   Hi,everyone,I'm a newcomer to ata and to forums,so be gentle with me.
   I live on a property on the mid north coast and am thinking of getting a 3kw solar system, I'm planning to mount panels on a rack on the ground {plenty of room},couple of questions:-1, what is the optimum angle to mount the panels? :-2,pro's and con's of the panels being closer to or further from the meter box? :-Is it better to mount the inverter closer to the panels or the meter box?
   In addition any advice would be appreciated,
   many thanks ben

   Posted Thursday 4 Oct 2012 @ 4:06:27 am from IP #
2. 

   Brendan C
   Member

   As I understand it, the optimum angles for solar PV as opposed to solar hot water are around the same as your latitude, so for example;
   12º - Darwin
   27º - Brisbane
   Just go to google maps to find your latitude.
   The closer the panels are to the house the less energy is lost. It is a small amount admittedly, but it's a small amount for every single hour of sunshine, which can add up to quite a large amount over the lifespan of the system.
   As far as I know the inverter has to be withing a certain distance of the meter box (but I could be wrong). I'm not too sure if that's an efficiency or electrical safety issue.
   Put them on the ground by all means, just make sure that the panel edges are not sitting on the ground. There are a few reasons, small though the individual effects may be;
   - to stop weeds and grass growing to the edges
   - to stop rain/dirt splashback off the ground
   - reduces possible damage/dirt caused by animals
   Dirt, dust will reduce performance.

   Posted Friday 5 Oct 2012 @ 4:25:24 am from IP #
3. 

   speedo
   Member

   If you're not mounting your system on your roof it would be a good idea to have your ground mounted rack adjustable to take advantage of the seasonal sun movements. You should enjoy about 10% improvement in output.
   There would only need to be three different settings:
   mid summer: Lat - 10°
   mid winter: Lat + 15°
   equinox: split the difference

   This link will give the optimal elevation angles. http://www.yourhome.gov.au/technical/fs67.html

   Posted Friday 5 Oct 2012 @ 6:25:36 am from IP #
4. 

   Greg
   Member

   I'll let the experts comment about regulations that might apply. All I can suggest is keeping all the DC runs short or use microinverters on the pannels and deal with just AC.
   There is a premium panel that has this as part of its design here -> http://www.tindosolar.com.au/our-panel/our-panel

   Not used them, not affiliated with them, just interested (if the rebate ever comes back or I win the lottery)

   Posted Friday 5 Oct 2012 @ 7:19:55 am from IP #
5. 

   alfresco24
   Member

   The Tindo Solar panel with integrated DC/AC inverter (Karra240) has very good spec's, with low temperature coefficient, made with premium brand materials, double the strength metal frame, and is rated for operation up to 85'C. However, it does come at a premium price around $3 per watt retail I think.
   The nice thing is that the 'balance of system' cost is very low because there is no separate DC wiring and special circuit protection - just standard 240VAC wiring that is easy to work with, relatively 'safe' and can connect into your mains wiring anywhere you want it to go.
   I dont know enough about them to offer a qualified opinion but the concept, technology and expected longevity is very sound.
   Keeping cable run lengths short and as thick (copper) as you can afford, is always very important to minimise energy loss through wiring resistance. Likewise keeping the number of wiring connections and connectors to a minimum is a very important, often overlooked factor in preventable losses in a system, and can boost the whole-of-life return on investment 2% to 4%

   Posted Friday 5 Oct 2012 @ 10:35:36 pm from IP #
6. 

   ben76da
   Member

   Hi, many thanks,brendan,speedo,greg,and alfresco, the links are very useful,I'll do a little home work on the inverter location and cable size. I'm wondering if the rack to support the panels could be built as a potting shed,it would be a little less intrusive in the garden.
   again many thanks ben

   Posted Friday 5 Oct 2012 @ 11:08:05 pm from IP #
7. 

   ben76da
   Member

   Hi,a couple more questions;- 1.is it better to have all the panels as a single string in series or a number of parallel strings?
   ;-2.where can I find a formula to calculate cable size from panels to inverter allowing for losses over distance?
   regards ben

   Posted Sunday 7 Oct 2012 @ 5:20:49 am from IP #

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