PV Project Started

[Nicedad]

Despite receiving this bad news about FITs over the weekend, as I type I am having five conifer trees removed to eliminate any shadowing on the PV panels. Strangely three of them are dying. The landscaper doing the work thinks they have been poisoned.     

[Nicedad]

Update:
Trees removed.
Frame structure that supports the PV panel assembly secured including the flat roof.
PV assembly frame fitted into position but without the PV panels.
Linear actuator fitted included a rather basic electronic tracker control from MTM scientific.

Its sort of tracking the sun but doesn't have the full travel I'm expecting. Yesterday afternoon after being connected up for the first time tracked the sun but was about 25 to 30 degrees behind.
This morning 08:30 when we briefly had a bit of half sun it tracked back from yesterdays final position but stopped 20 degrees short. So overall its travel is about 75 degrees instead of the 120 degrees that that should be possible.
Its the electronic tracker that limiting it. I don't like the circuit design. It has two photo cells and a comparator, but in effect there are two detector circuits as each photo cell compares against its own fixed reference. I have changed the reference circuit to make it variable (so that the two detector circuits can be sort of balanced and to optimise for the general weather condition) and will play about a bit more but may have to ditch it in favour of a RED Rock unit.
Trouble is if I do that will probably have to up the small PV panels use to drive it.          

[pontiff]

Just before I went I did manage to get something sorted as regards the PV installation. Brought three 230W panels and mounted them on a a 36 degree wooden frame. Connected up to first a 100A DP isolator and then Soladin inverter and an a.c isolation switch on the output and (just as a temporary hook up) plugged into a socket. I know it breaks 17th edition rules but didn't have the time before I went away to run cables back to the consumer board.
         

Hi nicedad,
Sounds like a great project. Which bit breaks the 17th edition rules? The plug? Was wondering if you  hardwire it into a socket to get round that issue. I want to connect it to a socket on my garage radial circuit cos running a cable back to the house would be a right pain.
Hope you can post some pics of your project when its ready.
Regards,
Pontiff
 

[Nicedad]

Fig 712.1 of BS 7671 2008 shows the a.c. output coming from the PV inverter through an isolator to the distribution board (in our case the consumer board) for the over protective device (fuse). It show the other side of the fuse on a common rail with the other non PV circuits within the consumer board to the supply meter. Unless you run the cable between PV and consumer board in steel conduit you will need to put in an RCD.   

If you were intending to register your PV system then an exclusive feed is whats expected.

I'm intending to run an exclusive feed back to the main consumer board and fuse it with a 'B' type RCBO.

I'll try and post one of the photos I have taken.

[Nicedad]

Ah.. Ah..  That works lets try another.

[Mudman]

very ineresting - thanks for posting the photos, would love to see more detail.
seems a lot of stress to put on the pivot - it doesn't seem substantial enough- and surely you need some cross bracing for the summer house structure and the truss- there'll be a lot of twisting forces when the wind comes round in turbulent gusts on a windy day and i'd suspect that those joints are not going to hold.. ...
MM

[Nicedad]

Quite comfotable about the pivot point. 
M12 stud through the centre of the 4" cross member fence post and 18mm marine ply. More of a problem was securing the body of the linear actuator, this is where the gusts on the panels will concentrate on. Its a metal fence post upright onto of the marine ply bolted through the plywood to more unistruct underneath locked into cross members.     

[Nicedad]

There are four castors at 90 degrees apart which carry the weight of the frame and panels. Thought initially that I might have to line the ply with 1mm sheet steel were the castors track but and the moment there's no sign of them bitting into the ply. Will see what the situation is like once the panels are fitted.

[Mudman]

 can see your joints now- pretty well formed by the looks of it- so are the castors quarter way down the two centre cross pieces?
very impressive- i'm considering ways to make a much smaller, possibly wall mounted, tracker on my roof terrace (5th floor) so will follow your progress with interest.
MM

[Nicedad]

Well after a spell working abroad have returned to the project. I did manage to install the panels in position before I left. But whilst away there was a problem with the tracker electronics. As previously posted I wasn't that happy with the electronics I had. They failed during the winter, the relays burnt out. I think this was because of the limited current handling ability of the relays and low charge of the batteries during the winter were not able to satisfy the tracker's demand with a reasonable time period and hence being in a demand status for much longer than expected.

Thinking this may happen I placed an order for red rock for one of their trackers.  Order placed 11 November 2009 but not delivered until 18 February 2010. Surfing the net have found out that this is not unusual. Yes they are probably the best trackers but the delivery is poor. I've also heard that other facets of after sales from them is also poor.

Nevertheless. Have installed the red rok tracker and it is very good. The angle of panel to sun is almost spot on, and the parking at the end of the day is a feature well worth having. I have also gone for a remote sensor with the battery and main electronics of the sensor being placed in my office 'indoors'.

Have also replaced the small solar panel feeding the tracker and storage battery. Now have a 20W PV panel in a fixed postion on top of my office and a 7Ah battery. I'm waiting on a cheap voltage regulator on order via fleabay at the moment to protect the battery.

All this tinkering is adding to the cost. Currently at £4.15 /Wp

[Nicedad]

After more overseas work have returned and thought I'd post the latest developments.

The red reck unit works fine, but was having problems with the tracker returning to its home position at the end of the day. I put it down to the cheap voltage regulator being overprotective such to the extent that on a sunny day the battery wasn't being charged properly. So I brought a more expensive regulator off ebay. Unfortunately although it improved things it didn't solve it completely.

I'v now put it down to the very low voltage presented to the actuator, its only 8.5v. I don't think its enough. So have just placed an order for a dc-dc converter from ebay (where would us tinkerers be without it). Rather than feed 12.8v into the red rock unit to give 8.5v to the actuator, I intend to up it to 20v (well within the red rok spec).

One the plus side, output slightly above expectations. The Soladin inverter does limit output to 525 watts but nevertheless have got 4.7kWh per day several times. On a good day it gets to max about 10:30 and stays there until about 16:00.  

Cost now at £4.23/Wp

    


      

[Nicedad]

The dc-dc converter has been installed with the voltage into the red rock tracker at 20v and outputting 17.8v to the linear actuator. It returns well at the end of the day. I've think I've got it working as well as I can now.

So on to building the summer house underneath.