Ground mounted solar PV installation project

[mike os]

So about 3k without batteries?

You are not going G98 then? or does the actual output still comply?
(watching with interest as i think i might do this)

 

[dobbslc]

So about 3k without batteries?

You are not going G98 then? or does the actual output still comply?
(watching with interest as i think i might do this)

I'm on the verge too only the worry for me is the fragile roof tiles and how the panels actually mount up there.

 

[brewdexta]

The battery component for 2.4kWh is £954, not £2.4K and this is the latest Pylontech, not an Aliexpress special. Its on 8 week lead time though, but that give me time to get it all up and running.

It will G98, the inverter is certified as such.

So cost wise, more like 4.5k ish without battery.

I'm going to get a battery as I'm a nerd and want to see how it goes and it will provide UPS for my techie stuff.

The inverter is quite nice, it has a no export function and a separate output for stuff you want to keep going during an outage, for example, beer fridge

Its the Sofar, HYD-3600-ES https://www.tradesparky.com/ecommerce/downloadasset?productAssetId=698929

Its has a max 3.68kw output to meet G98 specs.

 

[brewdexta]

The other two long lead time items have been ordered

I've ordered the Pylontech US2000C 2.4kW battery, it is known to play nicely with the BMS of the inverter I have
I've also ordered the Eddi 2.1 Solar diverter and relay board.

Both are on about 8 week lead time.

I'm going camping for a few days, when I get back I'll get the panels, isolators etc. i.e. stuff that can be delivered immediately.

Too far in to stop now

 

[addjunkie]

Integrated panels, supposedly the best way - hardly seen though. Is it worth the hassle?

I think so as they are holiday cottages and need to look the part too. One set integrated the other clagged on with 7nistrut would irritate me every time I looked at it.

 

[Kayos]

@brewdexta sounds like you have a solid plan.

I've been looking at a slightly bigger groundmount this week, due to a ridiculous planning condition it is now just under 3MW, fully self consumption via private wire so no grid connection at all
Will all be mounted to allow sheep to graze in the gaps

 

[m_c]

Given today's announcement, I'm reconsidering solar, but I'm struggling to find a definitive answer, so if you don't mind, I'm going to hijack this thread for a few questions.

The Sofar HYD inverter has two PV inputs. I'm assuming I could start with only using a single input?
Also, as long as I have enough panels to meet the minimum voltage, the inverter will do it's thing?


And how do you decide on solar panels?
I've got as far as Mono are more efficient/more expensive, with poly being less efficient/less expensive, but I'm guessing the rest is just down to picking whatever manufacturer/output/look/warranty/price you think is best?

At the moment, I was looking at the HYD-3600ES with these panels from TradeSparky - https://www.tradesparky.com/solarsp...a-solar-jam60s20-380mr-380w-silver-frame-mono
380W with a voltage of ~34V
6 x 380W would give just under the max single PV power input, but only about 204V output (MPPT operating voltage is rated 90-580V, with max power being 180-550V)
I'm assuming that if I was to add more panels to the string, the inverter will only use the max 2400W, with any extra energy unused, but have the bonus of more output on darker days?

 

[Gareth J]

Your roof and availability will probably dictate the panels. Some dimensions will tessellate better than others. If you're limited for space, you might decide to go for a more power dense panel than if you can max out a connection with cheaper/watt panels that take up more space.

 

[dobbslc]

@m_c although I'm a sparky I'm not that good with solar power as I'm only just starting to look into it all but as far as I know the PV panel voltage output is DC and that is fed into the inverter to change it into AC voltage. That will bring it to 240volt AC so you can use it to power your house. So your 204 v is DC not AC voltage.
@brewdexta is your man for all the technical stuff!
As @Gareth J said some roof's are a poor shape for solar panels mine included but I've seen some LG panels that are rated at something like 405 W so you can use fewer panels for the same output. There's a new type of panel called N type that produce more power for the same size as the older
type of panels. Might be worth checking out.
I've had half a bottle of wine so please double check any ranting from me tonight

 

[brewdexta]

Just got back from camping and waiting for a takeaway curry but will answer where I can tomorrow in more detail

Now I'm back I'll be ordering panels and isolators etc. With the latest announcement I forecast a run on panels too.

 

[dobbslc]

Yeah we should have got in a month ago

 

[m_c]

@dobbslc I should have probably mentioned DC.
I'm aware of what's AC/DC, it's just that there seems to be a lack of information about the various ratings, and what you can/can't do.

It really wouldn't surprise me if there's a lot of solar installers out there who don't know either, and just hope things work.

 

[brewdexta]

The Sofar HYD inverter has two PV inputs. I'm assuming I could start with only using a single input?
Also, as long as I have enough panels to meet the minimum voltage, the inverter will do it's thing?

Here's a good explanation of dual mppt PV inputs.

Dual MPPT Defined, Understanding Solar MPPT

It’s important to understand the definition of MPPT. Doing so can help improve the solar energy harvest of the solar installation to increase profitability.

www.solarpowerworldonline.com

The key phrase is "dual independent mppt" I'll check the manual to see if it states that. I don't think it does explicitly however my understanding is that apart from supporting different azimuths or different panel types per mppt string, it effectively provides two failure domains, i.e. if one string develops a fault, the other continues. That is just the same as only deploying one string so I think the answer is yes, you can deploy one if you wish.

Edit - page 32 of the manual says that the two MPPT inputs can operate independently.

Tomorrow I'll share my panel calcs.

My only solar experience up to this point is the single panel and victron solar charger on the camping trailer so caveat emptor

I've joined a couple of Solar farcebook groups. Apart from the usual sarcastic A-holes and people who can't be bothered to read a manual, there's some good info.

 

[J1nx]

Given today's announcement, I'm reconsidering solar, but I'm struggling to find a definitive answer, so if you don't mind, I'm going to hijack this thread for a few questions.

The Sofar HYD inverter has two PV inputs. I'm assuming I could start with only using a single input?
Also, as long as I have enough panels to meet the minimum voltage, the inverter will do it's thing?


And how do you decide on solar panels?
I've got as far as Mono are more efficient/more expensive, with poly being less efficient/less expensive, but I'm guessing the rest is just down to picking whatever manufacturer/output/look/warranty/price you think is best?

At the moment, I was looking at the HYD-3600ES with these panels from TradeSparky - https://www.tradesparky.com/solarsp...a-solar-jam60s20-380mr-380w-silver-frame-mono
380W with a voltage of ~34V
6 x 380W would give just under the max single PV power input, but only about 204V output (MPPT operating voltage is rated 90-580V, with max power being 180-550V)
I'm assuming that if I was to add more panels to the string, the inverter will only use the max 2400W, with any extra energy unused, but have the bonus of more output on darker days?

I based my system on roof size and getting the most panel area in a limited space.
After that it was whatever came up on eBay that could match.
I have 2.8kW of panels feeding a 2kW inverter, the excess is just not used but as you say, I get more power between startup and peak being reached and end of peak to sundown, also all days peak isn’t reached.
Id aim for the upper end of the MPPT operating voltage if possible.
If I could I would do a east & west array, the spread of power would be far more useful than outright peak for our uses.

 

[brewdexta]

Here's my panel selection calcs. First, the PV vital statistics of my solar inverter

Sofar HYD-3600-ES
Max PV input Wp 4790W
Max DC power for single MPPT 2400W @ 180 -520v
Max DC input current 12A per MPPT
Max DC input short circuit current 15A per MPPT


I looked at 4 different panels, first a JA Solar, the mac power current exceeded 12 amps. The below is for 6 panels, i.e. one of the two strings, so double the cost to get full system price. All the figures are at STC (standard test conditions) there are also NOTC (Normal operating test conditions) figures which are supposed to be closer to reality however it seems that STC is used to size systems so that is what I will use https://solardesignguide.com/stc-and-noct-solar-panel-test-conditions-explained/

6 x JA Solar JAM54S30-390 MR
£177.31 * 6 = £1063.86 = 45.46p per Wp
1722 x 1134 x 30mm
Power 390W * 6 = 2340
Open circuit voltage Voc 36.85v * 6 = 221.1v
Max power voltage Vmp 30.64v * 6 = 183.84v
Short Circuit current Isc 13.61A
Max power current Imp 12.73A

next up was another JA Solar panel, it met all the criteria

6 x JA Solar JAM60S20-385 MR
£167.97 * 6 = £1007.82 = 43.62p per Wp
1769 x 1052 x 35mm
Power 385W * 6 = 2310
Open circuit voltage Voc 41.78v * 6 = 250.68v
Max power voltage Vmp 35.04v * 6 = 210.24v
Short Circuit current Isc 11.53A
Max power current Imp 10.99A

I then looked at Canadian Solar, cheaper per Wp but quite low total max output as I'm aiming for 2395w per string, as max PV input Wp is 4790W, 2 x 2395 = 4790. There will be other Canadian Solar panels that probably meet these values better, I'm just looking at ones in stock at Solar Sparky at this point. I will look elsewhere too,.

6 x Canadian Solar CS3L-360MS 360W Mono 120C All Black
£147.49 * 6 = £884.94 = 40.96p per Wp
1765 X 1048 X 35 mm
Power 360W * 6 = 2160
Open circuit voltage Voc 40.4v * 6 = 242.4
Max power voltage Vmp 33.75v * 6 = 202.5v
Short Circuit current Isc 11.4A
Max power current Imp 10.69A

Finally, a Trina panel, this gets close to 2400, is a bit more expensive than the Canadian Solar, but a bit cheaper than the JA Solar.

6 x Trina TSM-DE09.05 390W Module Mono B/W 120C
£168 * 6 = £1008 = 43.07p per Wp
1754 x 1096 x 30mm
Power 390W * 6 = 2340
Open circuit voltage Voc 40.8v * 6 = 244.8v
Max power voltage Vmp 33.84v * 6 = 203.4v
Short Circuit current Isc 12.14A
Max power current Imp 11.54A

The price excludes the £125 for pallet shipping that Solar Sparky add on but include VAT.

You could argue that up t'north we are never going to see the max current figures so I could add more panels, however I'm limited to 12 panels space wise so its a non-issue for me and it also means that I'm meeting the spec of the inverter in case there's ever a warranty claim.

I'm probably going with the Trina panels, But I'm doing a final look around other place on price/availability first and I'll be adding in all the DC stuff that my spark won't have to hand like isolators to the order.

The inverter has an internal DC switch. It doesn't exactly define what this switches, just the PV or battery too? Either way, I'm probably having fuses and two pole isolator on both string inputs plus a fuse and isolator on the battery input.

Here's a couple of useful docs.

First an overview of G98, this is for when the output is <16A/3680W, it also discuss DNO notification, SEG and G99 and https://www.energynetworks.org/indu...generation-summary-guide-single-premises).pdf

And in case your spark is not sure about connecting Solar to the grid, here's the engineering doc. https://www.energynetworks.org/assets/images/Resource library/ENA_EREC_G98_Issue_1_Amendment_6_(2021).pdf

Page 23 has a simple example diagram showing position of DC and AC double pole isolators.

Cheers
Andy

 

[Maker]

I've only skimmed the thread so not sure if you've got it sorted, if you're still thinking about adjusting the angle I've got dozens of linear actuators that might be ideal for automating it, I'd be happy to send you some. You could use a MEMS gyro to monitor the angle and feed it into your data collection system to see how the panel angle correlates to the power output too.

 

[brewdexta]

I've only skimmed the thread so not sure if you've got it sorted, if you're still thinking about adjusting the angle I've got dozens of linear actuators that might be ideal for automating it, I'd be happy to send you some. You could use a MEMS gyro to monitor the angle and feed it into your data collection system to see how the panel angle correlates to the power output too.

Interesting

On day one I'm just setting them to about 38 degrees to get them earning their keep. Any optimisation will be phase 2.

I've incorporated adjustable angles into the design, but it would be good to see if it would work with linear actuators.

If you have a pointer to the spec that would be grand

 

[Maker]

I couldn't tell you the spec, there's loads of different ones. They're buried in the back of the shed but it's long overdue a tidy so I'll drag them out this week.

 

[brewdexta]

Solar panels, DC PV isolators, safety labels and a few other bits purchased so apart from a bit of cable and a few other isolators, fuses, most is now on order.

I've been away camping in the Norfolk Broads for 5 days, useful as I can see what the house base loads are when there is nothing going on. Looks like we use about 15kWh a day, the only things that are on during that time are a 2 freezers, a beer fridge, a large fridge/freezer, a few raspberry pi/network switches/WLAN etc. and a the usual telly/hi fi stuff on standby. The bore hole treatment plant also backwashes for 15 mins per night. I think the bulk of this will be the fridge and freezers so I will see if we can cull/replace the older ones with something a bit more efficient. The ones in the outbuildings are definitely well past their sell by dates.

 

[knighty]

a chest freezer with a new thermostat on to make it a fridge is way way more efficient than an upright fridge

could work well for the beer fridge?