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Author Topic: Ground Based Solar PV advice  (Read 4653 times)
nowty
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« Reply #30 on: November 26, 2018, 09:57:23 PM »

Second that, my garden ground mounts (ahem ladder stores of course onpatrol) are made of tantalised fence posts screwed together with galvanised coach screws and anchored to the ground with galvanised metaposts.

Use a cheap mitre saw to get easy 30, 45 and 60 degree cuts to give the required angles.

Then simply screw on the aluminium mounting rails for the panels.

And make a fancy border around the panels with deckboards if required.
« Last Edit: November 26, 2018, 10:05:04 PM by nowty » Logged

11kW+ of PV installed and 54+ MWh generated.
Lithium battery storage of 50+ kWh.
Hot water storage of 15+ kWh.
Heat storage of 15+ kWh.
6kW Ground source heatpump.
EV BMW i3 (another 30+ kWh's of storage).
250,000+ litres of water harvested from underground river.
Home grown Fruit and Veg.
eabadger
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« Reply #31 on: November 27, 2018, 07:16:40 AM »

made ours out of scaff poles and joints, the whole thing tilts for winter/summer sun height

steve.


* IMG_0794.JPG (135.11 KB, 640x480 - viewed 286 times.)

* IMG_0753.JPG (178.53 KB, 640x480 - viewed 287 times.)
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1600w PV main array at 24v, excide 2v 1000a forklift cells now x 2, 320w PV secondary array at 12v. Enfield 1944 ex RAF 5.6kw diesel genset (now in pieces, big ends gone), Petter AC1 28v diesel charging set at 2.8kw.
1kw wind turbine.
26kw wood stove back boiler to underfloor heating and dhw
charlesd
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« Reply #32 on: November 27, 2018, 08:41:49 AM »

Thanks for the ideas guys. I have looked through some older threads and the scaffold poles frame looked like a great idea. Unfortunately I don't have any spare poles so whatever I get would have to be bought. 50mm box is not really any dearer than scaffold poles if your buying and square is easier to weld. I'm not keen on wood I'm having enough issues with tanalised fenceposts needing replacing in under 5 years in some cases and I'm worried about it warping over time.
I might do a combination a steel subframe with wooden rails to attach the panels too would stop the interaction between the steel and aluminium. I'm going to mock up a model before I start so I can finalise the design. I'll post a picture when I've done it if I can work out how.
Cheers Charles
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eabadger
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« Reply #33 on: November 27, 2018, 11:07:00 AM »

hi,
i could have, but didnt weld, see attached joint system, used unistrut for rails, made attachment a doddle.

steve


* IMG_0719.JPG (95.02 KB, 640x480 - viewed 266 times.)
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1600w PV main array at 24v, excide 2v 1000a forklift cells now x 2, 320w PV secondary array at 12v. Enfield 1944 ex RAF 5.6kw diesel genset (now in pieces, big ends gone), Petter AC1 28v diesel charging set at 2.8kw.
1kw wind turbine.
26kw wood stove back boiler to underfloor heating and dhw
todthedog
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« Reply #34 on: November 27, 2018, 03:45:09 PM »

Made mine with box, bolted not welded. Living in France at the time scaffold poles not an option.
 I would have used them if available. I made sure the bottom was clear of the ground to allow easy strimming.

A copy of this design
https://www.builditsolar.com/Projects/PV/DougEnphase/DougEnphase.htm

With perfect hindsite maybe I would have allowed for changing between summer and winter settings.

Despite the brilliant engineering of Clockmans trackers I am unconvinced that the increased production is worth the effort, complication and expense. I think that if the money is available I would stick to simplicity and more panels.
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eabadger
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« Reply #35 on: November 27, 2018, 04:40:03 PM »

my thoughts exactly TD.
but i had poles to hand so.....
the tilting sure makes a big difference, the original fixed array is outputting far less currently.

steve
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1600w PV main array at 24v, excide 2v 1000a forklift cells now x 2, 320w PV secondary array at 12v. Enfield 1944 ex RAF 5.6kw diesel genset (now in pieces, big ends gone), Petter AC1 28v diesel charging set at 2.8kw.
1kw wind turbine.
26kw wood stove back boiler to underfloor heating and dhw
charlesd
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« Reply #36 on: November 27, 2018, 04:46:32 PM »

This was the design I saw first and thought looked simplest I was just going to swap the poles for 50mm box. Then I thought it should be simple enough to hinge the front support and make the rear support in 2 sections that slide past each other then just bolt them together at certain points to allow adjustment of the angle. Nothing complicated just simply loosen the  bolts slide it up or down to adjust and re tighten. The plan is to make the array in 3 sections each with 6 panels on each so I don't have to move the whole lot in one go. The additional steel parts and time to make it adjustable will probably be negligible in the scheme of things, and if I don't think it makes a difference I'll just leave it set in one place.

On a completely different note I'm trying to work out roughly the size of cable I would need. Most of the cable calculators I've tried online seem more suited to 240v ac stuff and I'm trying to estimate what I will need for approx 5kwh of panels running around 100m to the inverter. I'll ultimately check it all with my sparky but I'm just getting ballpark shopping list ready.

Cheers Charles
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smegal
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« Reply #37 on: November 27, 2018, 05:11:40 PM »

This was the design I saw first and thought looked simplest I was just going to swap the poles for 50mm box. Then I thought it should be simple enough to hinge the front support and make the rear support in 2 sections that slide past each other then just bolt them together at certain points to allow adjustment of the angle. Nothing complicated just simply loosen the  bolts slide it up or down to adjust and re tighten. The plan is to make the array in 3 sections each with 6 panels on each so I don't have to move the whole lot in one go. The additional steel parts and time to make it adjustable will probably be negligible in the scheme of things, and if I don't think it makes a difference I'll just leave it set in one place.

On a completely different note I'm trying to work out roughly the size of cable I would need. Most of the cable calculators I've tried online seem more suited to 240v ac stuff and I'm trying to estimate what I will need for approx 5kwh of panels running around 100m to the inverter. I'll ultimately check it all with my sparky but I'm just getting ballpark shopping list ready.

Cheers Charles

Try this:

http://www.solar-wind.co.uk/cable-sizing-DC-cables.html
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TT
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« Reply #38 on: November 27, 2018, 06:48:46 PM »

Why not put the inverter in a small kiosk at the end of the panels and then run 230vac back to the house.
Keeps the dc cables and losses low.
Then a swa back to the house, along with a cat 5 or 2
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charlesd
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« Reply #39 on: November 27, 2018, 07:44:20 PM »

Quote

Thanks

I'm assuming 40v per panel so 18x40 is 720v
A 5kw system so 5000/720 about 7amps
That gives me 4mm cable over 100m with 1% loss that seems ok to me assuming I'm putting ok numbers in.
I would probably use 6mm to allow for a bit of future expansion.
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marshman
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« Reply #40 on: November 27, 2018, 08:07:47 PM »

Quote

Thanks

I'm assuming 40v per panel so 18x40 is 720v
A 5kw system so 5000/720 about 7amps
That gives me 4mm cable over 100m with 1% loss that seems ok to me assuming I'm putting ok numbers in.
I would probably use 6mm to allow for a bit of future expansion.

You might want to consider splitting into 2 strings of 9 panels. The reason is that 720V is quite high and may well be above the maximum input voltage of an inverter. 360V is better and should give you more choice of inverter. So you need to redo that calculations based on 14 amps.

Personally I would prefer TT's suggestion of a small cabinet next to or underneath the PV panel mount and running an SWA AC cable back to the consumer unit. A lot of inverters have a decent IP rating.

Roger
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3.15kWpk (15xSharp ND210)/SB3000. & 3.675kWpk (15 x Suntech 245WD)/SB4000TL, 10kW GSHP driving Wirsbo underfloor heating from 1200m ground loops. 10' x 7' solar wall (experimental). Clearview 650 Wood Burning Stove. MHRV - diy retrofit. Triple glazing.
charlesd
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« Reply #41 on: November 28, 2018, 07:46:58 AM »

If I mount the inverter near to the panels. Does it need any a.c. power of its own as well or will it just work from the power from the panels? Also most inverters seem to need access to Wi-Fi and there's no Wi-Fi in the panels location would I also need to resolve this somehow?
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JohnS
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« Reply #42 on: November 28, 2018, 08:03:48 AM »

The inverter will have AC power.  It comes from the same cables that it feeds the power out to the consumer unit/henley block and thence the house and the grid.   Wink  Grin

You don't need a separate cable.

As regards wifi, it depends on how obsessive about measurement you are.  I get by with a cheap energy monitor clamped on a cable into the henley block.  It displays real time output and daily output.  Plus weekly meter readings.
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TT
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« Reply #43 on: November 28, 2018, 08:04:50 AM »

The inverter doesn't need a separate supply to work.
Cable from solar panel to inverter
Inverter to consumer unit.

A cat 5 cable may resolve the Wi-fi issue if the inverter has a Ethernet connection.

I have no Wi-fi connection or cat 5 cable  just simply read the meter every 3 months, I'm not interested in data, spreadsheets etc that's just me.
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charlesd
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« Reply #44 on: November 28, 2018, 08:11:52 AM »

The inverter will have AC power.  It comes from the same cables that it feeds the power out to the consumer unit/henley block and thence the house and the grid.   Wink  Grin

You don't need a separate cable.

As regards wifi, it depends on how obsessive about measurement you are.  I get by with a cheap energy monitor clamped on a cable into the henley block.  It displays real time output and daily output.  Plus weekly meter readings.
Thanks John & TT
Seems each time I think I understand something it gets a little more complicated Smiley
But I think it now seems the most sensible idea is locate the inverter near the panels. Them as 2 strings of 9 rather than one of 18 to lower input voltage and probably include a data cable alongside the a.c. cable for monitoring the inverter should I wish too.
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