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Forum Index : Solar : I’m going off grid
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KarlJ Guru  Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
FYI earlier link to 48V battery bank is a disaster waiting to happen. should not ever have more than 2 strings of batteries in parallel and better yet should be done with single cells vs 12V batts. Luck favours the well prepared |
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VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
Hello all, The racking system that was supplied was a mess! Rails were short, clamps were for 35mm panels and not enough of them. When I'm ready for the next stage of the install I will have the correct rails, clamps and mounting hardware. I have just found a solar wholesaler in Perth with the correct complete rail system and it will be installed to standard. It is as it is so that I could get what I had up and running ASAP. Also I have a tablet PC with remote access to monitor the system remotely. As to the batteries, I will have a single string of 12 volt batteries just a bigger capacity. Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Interesting project. Regards to panel orientation, have you considered getting the panels off the roof? My thoughts have always been if I did something like this I'd have them is a bit of open space & try & implement a tracking system. I always think things like Pergola to sit under or shade for who knows what. For tracking mechanisms my thoughts are alone the line of how old louvered windows operate. Doesn't seem like a huge fabrication challenge. Beyond that, the logic & drive should simple. I probably get this mentality from camping experience, where I cart the panels about all day & get really impressive returns. Cheers Phil |
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| VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
Hi Phil At first I was a bit worried about how much sun I would be able to make use of with the east facing orientation, but the morning after I connected everything up and with a 62% SOC I found that even in overcast conditions the system could produce enough to charge the battery bank to full by 11am. Now keep in mind that at the moment the inverter only has a load of about 60 watts and after a few days the SOC would drop down to about 78% by first light and be fully charged by 10am or so. This will change dramatically when I'm staying at the shed and using lights, fridge etc to the point that I would need to run a gen-set to top up the batteries before bed so that I don't over discharge the bank. But with a larger battery bank and the extra panels added to the system, this will sort itself out. When I did my installers course we discussed the issue of correct orientation, tracking systems and ground mounting the array. My conclusion was that the ground mounting method with correct orientation was the best method but also the most space consuming method. OK if you have the space. One thing we did was to calculate the losses due to incorrect angle, orientation, partial shading etc and we found that in most cases by adding an additional panel to the system was enough to overcome the losses. And this is ok if you have the room for an extra panel or two and the money to pay for them which I did. My panels are shaded in the morning up to about 9am, but during the very few sunny mornings that we had while on the block once all the panels were in full sun I was producing over 1200 watts, and by 11:30 I had reached max power for the system. (it was only about 11 degrees in the sun so panels were cool.) Max charging current recorded was 23 Amps. And at one stage I saw 1900 watts but this dropped off once the temp rose above 15 degrees. IMHO adding an extra panel or two is far easier and cheaper that having a tracking system but everyone has their own opinions and every system is unique with it's own layout and sizing issues. Regards Matthew Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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| VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
Just another thing I'd like to mention is that I'm also using the panels as shade for the shed to help lower inside temps over the hotter months. I do have insulation in the roof but every little bit helps..... Just something to think about when planning these things. Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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| VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
Just a short update on my off grid system. The system has been running for over three months and even in the very poor weather that we have been having the system is running very well. Next trip down I will be adding another three 300 watt panels to the system and I have started saving up for the new larger capacity batteries for the new battery bank. I have had a for issues with my tablet loosing comms and haven't been able to see how the system has been going over the last week or so, but I have other equipment that tells me that the system is still working. Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Good to hear its been working for you, sounds like the off grid bug has bitten. 
Keep an eye on ebay for 2nd hand panels, I bought 8 190watt 24v panels this time last for about $80 each from memory. They were from an electrician who upgrades solar grid connect systems. The panels were about 3 years old. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
Hello, Another update on my off grid system. I purchased the new racking system including mounting feet and clamps and I've installed it all on the west side of the shed. I then mounted the 3 new 300W panels and moved the existing 6 panels so that all 9 panels are on the west side.            Still have issues with the clearance around the edge of the roof and the panels, but it's as good as it will get. North and South edges have just on 200 mm to the edge and the front has 120 mm not including the gutter. I also need the get and install isolator covers which will get done on the next trip. Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Looks very professional, any plans to prune the trees shading the panels? There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
Hi Madsness, Yes, next trip I'll will be removing the top few branches on two trees but nothing more. Once I get the extra panels and install them back onto the east side I'll have more than enough capacity with some shading. Trimming the trees will give me an extra hour or so shade free in the afternoons so I think that is still a good result. Shading starts at just on 2:30 and the next big shading from the rest of the trees starts at about 4 ish. Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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| flc1 Senior Member  Joined: 20/11/2011 Location: New ZealandPosts: 242 |
nice setup , yep hack into those trees |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yeah I would give the trees a good trim. I'm a greenie, but if a tree is in the way or dangerous, its gets removed. My rule of thumb is for every tree I cut down, I plant 2. The panels are now giving shade to the shed, so it should be cooler, provided the air under the panel is free flowing. Your harnessing renewable clean energy too, so that more then compensates for removing a few branches, plus trimming the trees will reduce the leaf litter in your gutters, a big plus if your in a bush fire area. The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| M Del Senior Member Joined: 09/04/2012 Location: AustraliaPosts: 155 |
Nice looking set up, wish my shed was that wide. Suburbia, gotta love it  .What brand are the roof brackets and where did you get them? I have been looking for profiled CGI brackets for a number of years and so far found nothing. Mark |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Totally common sense philosophy Glenn, there should be more of it. Got a few unsafe nuisance trees around here that need to go. I'd be happy to see them gone & replace 3:1 even, with them appropriately placed. Unfortunately it's not likely to happen. Phil. |
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| flc1 Senior Member Joined: 20/11/2011 Location: New ZealandPosts: 242 |
yep,can always just give them a heavy cut back, they should keep growing, why cut them right out if you don't really have to. |
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| VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
Hi M Del, My shed is only 6.2 m wide, so and same size as a double garage/carport. Solar racking system is from Alzone solar on Ebay. http://www.ebay.com.au/itm/Alzone-Solar-Corrugated-Feet-with-Isolation-Pads-Bolts-x-6-units-/272352368695?hash=item3f697 75837:g:v3YAAOSwGvhT8Wld Expensive but well worth it in my experience. There is also a rail that can screwed direct to the roof. Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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| M Del Senior Member Joined: 09/04/2012 Location: AustraliaPosts: 155 |
Thanks VK6MRG, nice system they put together. Beats our self pressed ones for looks and uniformity, unfortunately yes, expensive. The usual trade off. But it is easier than cutting bending and pressing individual ones. My shed is only 3.6m wide, but it is 12m long. Going 2 up sideways I can fit 14 or 16 panels on the NE side of the shed, 4kw. Plus the current 1kw on house,5kw NE. Add 2kw on the houses NW roof and that's me set up. Mark |
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| VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
 Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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| VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
Hello everyone. Just a short update on my off grid system. As it is getting closer to battery bank upgrade time I thought it would be a good time to get some sort of balancing system and a monitoring system to keep an eye on the individual batteries in the bank. I got a HA02 Battery equalizer to have a play with and after seeing the difference it makes in such a short time (not hard with the size of my test battery bank) I'm sold on the unit.  I have been trying to design a circuit to connect to my Web Site in a Box so that I could monitor each battery's voltage in the bank so I can track the battery's condition. After several failed attempts at this I was on the hunt for isolation IC's when I stumbled on this.  For a complete overview on the Isolated six channel Volt Meter have a look here. It is connected to my windows 7 PC via a USB cable and once I’m remotely logged in to the PC will be able to see the voltages of the batteries. The monitoring software also has logging functions so that I can track any problems I may have down the track. So, I have it connected to my test battery bank on the bench and it is awesome.  The silver box is my 48 volt dc power supply that I built a while ago. Output is only a few amps with an open circuit voltage of 56.8 volts and comes in handy when wanting to test bits and pieces and or charge my test battery bank. This is what the battery voltages looks like when charging the battery bank with no equalizer connected.  And the battery bank with the battery equalizer connected.  And the voltages of the batteries with the battery equalizer connected.  I have also purchased a battery bank desulfator and when it turns up I'll add in some photos. Regards, Matthew Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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