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3 Phase Install in Cape Town


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Although I have documented the crap out of my install here -> http://goingsolar.co.za , I thought it would be nice to put info up elsewhere.

 

I decided I wanted a solar install sometime in early 2011, "for the planet" and totally not because Eskom was making announcements about the imminent end of civilization^H their infrastructure, and can they put the price up like 300% please Mr Nersa.

 

As my house is currently 3 phase, and we do have some 3 phase equipment in use, I decided I'd go 3 phase.

Its not that different to single phase, just means you need a different inverter.

 

The panels I wanted to buy (as they were by far the cheapest / best bang per buck) were 36V/8A panels.

Panels will decide what inverter to get, as you need to match the voltage input to the inverter.

 

The next decision was then finding a suitable 3 phase inverter.   I visited the SNEC trade show in Shanghai, took a look at a few options, and decided on a Growatt 10KW grid tied inverter.

 

The Growatt inverter has 2 MPPT string inputs, and I designed my install to use 2 x 15 panel strings.

For various (cable size!) reasons, you usually wire up larger installs in DC voltage vs current AMPs, so I decided on 

36V x 15  = 540Volts @ 8A per string.

 

The inverter works from 300V - 1000V, so I was fine on that choice.

 

Photos of the 2013 trade show here - https://www.flickr.com/photos/sheedl/sets/72157633500979664/

 

My Inverter - http://ginverter.com/html/2014/01/08/2014010803400724189014.html

 

I'm quite happy with the inverter - it does its job, and Growatt has even done the NERSA certification to make it legal in South Africa if I do go SSEG at some point.  They were nice enough to send me the certification unasked in May this year after they passed, as I was pretty much their first South African customer in a domestic level (they usually do commercial installs here).  Good aftersales service!

 

 

10KW was more than I needed, its about the smallest commercial size available for 3 phase inverters, and also gives me ample room to grow my system.

 

I eventually started buying stuff in 2012, and shipped stuff over from Shanghai (where I was living), over to Cape Town in late 2013.  As the main costs in shipping are not shipping, but clearance, I decided to go a little overboard on requirements, and bought myself 30 x 300W Cotech panels.  When I bought them in 2012, they were R850+vat in China @ R1.3 per RMB for 300W panels.  The inverter cost me about 12k rmb @ R1.3 to the RMB.  I also bought a mounting system from NiceSolar.cn (german design mounting), for 480$ US.

I also bought and setup all the other electrical bits n bobs whilst I was in China, as prices are, um, quite a lot cheaper than here.  Lets just leave it at that.  #$%$#% overpriced local stuff, grrrr.

I got lucky in that most of what I bought was @ R1.3, although by the time it shipped the Rand had dropped quite significantly.  We're closer to R1.6 to the RMB at the moment, and it was R1.7 earlier this year! 

 

Despite a few hiccups (the clearing agents were... afrikaans word for box translated into english, and the charges were R20k more than they should have been due to their incompetence), it all arrived ok.

 

The pallet container for the panels sat in my front yard for about a month before I got around to moving it into the back and looking at install.

 

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This eventually got moved to the back garden, after I finally had the courage to open the shipping pallet to see if anything was damaged.  Thankfully, all the panels made it in one piece, and no glass was broken.

 

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[writeup in progress - this is part 1]

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My house is an older Victorian model - it predates electricity, and pretty much all the plugs and wiring are mounted externally.

This is good, because all the fittings are quite cool looking, but its bad in that if you want a new plug point or wiring, you need to run it externally, or bash through walls and run conduit, then repair.

 

Example of current house wiring style circa 1930's below

 

post-393-0-30673400-1403333124_thumb.jpg

 

With this caveat, next up on the agenda, was to run some wire through the house.

I had builders in doing renovation, so I got them to do it.  It involved putting  a new drop ceiling in at the back of the house, drilling holes, gouging brick to put in conduit, sealing up again with concrete, then finally running cable.  I'm quite happy to have outsourced that part of it!

 

post-393-0-91257800-1403333178_thumb.jpg

 

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That took about 2 days to run.

 

We also mounted the inverter, and the electrical in the back storage room I deigned suitable for the inverter (and eventually batteries when I go offgrid).

 

post-393-0-04603100-1403333485_thumb.jpg

 

This ran all the way to the front of the house to the main DB panel

 

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Next step was to mount and install panels on the roof (if the annoyingly astute look at the photos, you may see that the panels were gone in the photos, it was done at the same time as the cabling, don't be pedantic)

 

I roped in my cousin to assist, and we took the mounting system up on the roof, and looked at how to install.

We mounted one test panel, and installed about 3/4 of the mounting on the first day. 

Even though it was our first ever install, it went surprisingly fast.  We were pretty much done in 2 hours.

 

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Farmer Joel with our one test panel installed in the background.

 

The second day we roped in more workers (my extremely reticent (aka lazy) brother, and his much less reticent girlfriend), to assist in moving 15 more panels to the roof.

 

This took us about 1 1/2 hours to move + install.

 

post-393-0-80802700-1403333947_thumb.jpg

 

If I was doing it again, I'd definitely be able to do it in 2-3 hours with 3 people.

 

 

I waited till evening (as then the panels would be dead / safe to connect), and wired up the DC side, and started on the AC side.

 

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Next morning, I eagerly anticipated the system coming on, and powering up the inverter.

(The AC side was left unconnected, as I hadn't finished cabling, and wanted an electrician in to double check before I connected up)

 

It didn't come on  :(

 

A little troubleshooting later, I discovered that the DC switch I bought for safety purposes didn't work, and it actually self immolated itself slightly later on in the day!

 

Once I removed that from the wiring, things were working as expected.

 

 

As a background, I went overboard with safety.  

At the DC input side I had lightning protectors (the orange things in the photo), and DC on / off switch to isolate the inverter from the panels.  

 

The Inverter also has a DC on / off switch.

 

Output goes to a 400Va/ 60A trip switch (the bottom right), that goes to the front of the house to another 3 phase on / off SISO switch, and there is wiring  to provide single phase on circuits for that room (bottom of the larger box).

 

 

Once it was working - eg inverter was happy, voltages looked good, we wired in the front db.

 

Its been working since November last year, and we've generated 3.67MW since then as of... today.

 

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The wiring is slightly tidier, but I still need to do some stuff like put a laptop there for recording PV input / output.

 

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I think that pretty much covers the install!

 

I have lots more pics on my flickr account here - https://www.flickr.com/photos/sheedl/sets/72157634043381722/

...and a lot more info on everything here - http://goingsolar.co.za

 

Ask questions if you want more info!

 

Lawrence.

 

 

 

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Things I did prior to my install.

 

One of the first things you do when doing a solar install, is to optimize current use.

 

So, in 2011, I had solar heating installed.  I had 300L installed, and got R16k back from Eskom for doing it, so the install cost came to about R14k

Well worth it, and its already paid for itself in less than 2 years.

 

(lots of photos here)  https://www.flickr.com/photos/sheedl/sets/72157631696459156/

 

That brought our +- monthly R1200 bill down to about R650-700

Next up was replace the entire house lighting with LED's.

 

That didn't really have much effect on the bill, but it helps.  I think it probably brought the bill down about R50 or so a month.

 

I also ordered a monitoring system for electricity - I got a Flukso - http://www.flukso.net so I could see what the average usage was.

Currently we sit at about 15KW a day on average (less what we generate in the day), with the weekends going higher with washing etc.  I've moved most of the usage to daytime, as electricity is "free" then for us.  

 

I plan on bringing that down even more, as most of that is Fridge, Freezer, and some Desktop computers. I'm toying with taking some of that completely offgrid on one phase.  It will be nice to be free of unreliable Eskom, but then it does mean more money spent on inverters and a  BMS (battery management system), plus batteries.  

I'd love to make it entirely offgrid on 3 phase, but its just too expensive to do so at current prices.

If I did that I would definitely get more panels up.

 

Currently we use one string of 16 panels -  I didn't mount the other 14 due to needing rigging etc, if i went off grid, I'd probably put them up, so that winter usage is definitely covered.  Right now winter provides about 10KW a day I think, vs 35KW-40KW in summer.

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  • 9 months later...
  • 3 years later...
  • 10 months later...
  • 6 months later...

That system is offline now, as I've moved most of my panels to another location.

The house my 3 phase setup was installed in is rented out, and I didn't trust the tenants with not farking up the batteries.
I'll move most of the equipment at some point to my new house once finished next year.

My current setup is now mostly Victron based.  10KW  LFP Renov Battery + 48v 3KW + 12 Panels + FM80 (soon to be replaced with a Victron 150/80 MPPT solely for the logging, as my accountant is updating his system)

Growatt was excellent in terms of support, although I dealt directly with them in China.  
Like I mentioned, they actually contacted me to let me know that they are NERSA certified, and "legal" to install.

Their equipment is pretty solid.  It just works.  I bought the low end industrial stuff though, so YMMV.  

I'm still running on the pallet of panels I brought in 10 years ago...  Some wear on those - although I've moved the ones i'm currently using, around between 3 locations now.
Still pulling in the KW so all good.

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