A bit of advise please ? Well a lot !

[tabtrade]

I'm looking to build a small system myself , a have a basic electrical knowledge so far as I could rewire my house but would have it checked and signed off by a pro. I just want a small maybe 1000 watt or so system grid tied . I'm not fussed a bout feed in tarrifs or anything back from my supplier ,just want to produce a small amount of juice a knock a few quid of my annual consumption. Probably 4-5 2-300 watt panels and a grid tie inverter ?

My house is west facing so I am probably going to locate the panels on my garage as this is south facing , will this be ok it has Quite a shallow pitch ? Is there an optimum pitch ? I'm in the UK Midlands area , Also is it ok to connect an inverter to the consumer unit in my garage ? It's approx 30 meters form the house consumer unit ? The garage consumer Unit is connected to its own breaker in the house consumer unit and has armoured cable running underground ? Is this ok ? Or do I need to connect the inverter direct to the house consumer unit .

What inverters would people suggest ? Sunny boy , growatt goodwe 1-2kw etc or should I go for a couple of the mastervelt soladin 600 inverters and maybe have 2 600 watt systems ? The soladins simply plug in to the nearest outlet to feed back in so again if I locate them in my garage is it ok to connect them via the sockets in my garage ?

I am in the uk and from what I have read there doesn't seem to be any legislation to say I can't have a Diy system only that it needs to be g83 and have anti islanding ?

Also our meter is a prepay type , we top up a card at the shop and put the card in the meter to load the credit , what's people thoughts on this ? Is it ok to have a pv system if you have a prepay meter ?

Sorry for all the questions just need some advice and guidance .
Thanks in advance for any help and pointers
Steve

[bvmm]

A comment or two in response to your questions:
- optimum pitch (panel slope) is close to your latitude if the roof points due south (Azimuth 180 degrees). If you use the PVWatt calculator (http://pvwatts.nrel.gov/pvwatts.php) you can get a sense of the sensitivity of production to panel pitch. The attached figure gives a sense of how the optimum pitch (to my understanding) varies for roofs that do not point due south (the right hand scale depends on the size of your proposed system. Optimum Pitch For Various Azimuth Angles.png
- look at the roof to understand if/when it's shaded. "Hard" shading (tree, pole, chimney) reduces power by about 10X the area of the panel shaded.
- I have not expertise with regards to the electrical side of what you are considering.

[tabtrade]

Thanks bvmm , I have looked at the pv watts page before and left a little confused . Been back today and even more confused ! When entering my location it auto enters 20 degrees so not sure if it suggesting that's the ideal tilt . However reading on the forums etc it suggests my latitude plus 15 degrees , this would give a tilt of 68 degrees but when I enter that in to the pvwatts calculator it reduces the power produced , however I did have a play with it and the most power produces suggests a tilt of 25 degrees , significantly less than the 68 that was first suggested . So suffice to say it's all very confusing but a good learning curve , thanks very much for you help

[Raul]

I'm looking to build a small system myself , a have a basic electrical knowledge so far as I could rewire my house but would have it checked and signed off by a pro. I just want a small maybe 1000 watt or so system grid tied . I'm not fussed a bout feed in tarrifs or anything back from my supplier ,just want to produce a small amount of juice a knock a few quid of my annual consumption. Probably 4-5 2-300 watt panels and a grid tie inverter ?

My house is west facing so I am probably going to locate the panels on my garage as this is south facing , will this be ok it has Quite a shallow pitch ? Is there an optimum pitch ? I'm in the UK Midlands area , Also is it ok to connect an inverter to the consumer unit in my garage ? It's approx 30 meters form the house consumer unit ? The garage consumer Unit is connected to its own breaker in the house consumer unit and has armoured cable running underground ? Is this ok ? Or do I need to connect the inverter direct to the house consumer unit .

What inverters would people suggest ? Sunny boy , growatt goodwe 1-2kw etc or should I go for a couple of the mastervelt soladin 600 inverters and maybe have 2 600 watt systems ? The soladins simply plug in to the nearest outlet to feed back in so again if I locate them in my garage is it ok to connect them via the sockets in my garage ?

I am in the uk and from what I have read there doesn't seem to be any legislation to say I can't have a Diy system only that it needs to be g83 and have anti islanding ?

Also our meter is a prepay type , we top up a card at the shop and put the card in the meter to load the credit , what's people thoughts on this ? Is it ok to have a pv system if you have a prepay meter ?

Sorry for all the questions just need some advice and guidance .
Thanks in advance for any help and pointers
Steve

You can't back feed (grid tie) without consent from your electricity provider, if you get caught you get disconnected. Grid does not belong to you. Usually there is ping pong paper work with the relevant grid authority then once approved a installation can commence. They will only talk to recognised approved installers(MCS registered).
Check REA and MCS for regs as in what you can do.

[bvmm]

Interesting.

For a system facing south in Birmingham, PVWatt gave me a peak at 39 degrees, or about 13 degrees less than the latitude. The chart above is from my own tool and situation (45N) and it suggests a peak 3 degrees less than latitude - however this tool ignores weather. Since PVwatt pays attention to weather, if your location is mostly grey in the winter and adjacent months, then this would suggest positioning the panels to favour the times in the year (i.e. summer) most likely to see sun. My tool suggests a peak at 47 degrees - 8 degrees higher than PVWatt. This suggests that weather may be a significant factor in the angle PVWatt suggests for Birmingham.

(I think 20 is the default pitch in the PVWatt dialog, irregardless of location).

[tabtrade]

Thanks Raul , that's good to know , looks like I'll not be having a grid tied system then.



You can't back feed (grid tie) without consent from your electricity provider, if you get caught you get disconnected. Grid does not belong to you. Usually there is ping pong paper work with the relevant grid authority then once approved a installation can commence. They will only talk to recognised approved installers(MCS registered).
Check REA and MCS for regs as in what you can do.



[/QUOTE]