Ground mounted solar PV installation project

[Gareth J]

Hurry! The daylight hours are slipping away!

Smart job by the way. Put a set on a 10° tin roof in the spring. The amount of dirt they accumulate compared to steep ones is astonishing. Easy enough to clean though. Yours will be even easier

 

[dyno-tron]

Hurry! The daylight hours are slipping away!

They are - short days and some of them very dull, but there is still some useful sunshine to harvest, we have averaged approx 13kwh per day so far from our 7.3kw system this month. Some days poor, some days very good. The battery makes a huge difference:-)

Looking forward to a bright November.

 

[minimutly]

They are - short days and some of them very dull, but there is still some useful sunshine to harvest, we have averaged approx 13kwh per day so far from our 7.3kw system this month. Some days poor, some days very good. The battery makes a huge difference:-)

Looking forward to a bright November.

Good luck - generally this time of year you will be at 10% of the best (summer) days. So, @brewdexta don’t be too disappointed when you see what you’re getting. If you’re lucky enough to get some frosty weather later on they will work well, despite the sum being low in the sky.

 

[brewdexta]

I've done lots today, but not much to show for it. I installed a wireless access point into the solar shed as the control of the inverter defaults to wireless.
I did this via a POE injector so its independent of the system power wise.

Next I cabled up the current
Not sensor.

I also built a door to the solar shed out of some scrap OSB and some old T&G oak boards that have been knocking around the barn and workshop for years.

Some have cement on them, others have been walked on with oily boots and others are just soaked in oil.

A bit better after a sanding.

A coat of somd kind of Osmo anti fungal treatment that was hanging around in the barn. Difference in the wood soon shows up but as a door to the solar shed, it will be fine. It needs a couple more coats of oil but that can be done just installation as it's on the leeward side

Should be finished tomorrow.

 

[brewdexta]

I got all the earthing and DC cabling completed at the weekend so I sneaked out at lunch time and switched it on. Its a very dull cloudy day but didn't expect much. I think its a couple hundred watts at the moment but was higher an hour or so ago when the cloud receded a little. So it was 860W in, 20W from the grid, 270W going into the battery and 610W being used.

I'm still setting up the logging but I think this graph shows the impact, this is generated by the LED on the meter that flashes for each Wh used, so less flashing, less use

I didn't expect a massive amount of generation this time of year, hence why I have only bought one battery at the moment. I'm just glad its all working

The spark is coming around later to give it all a good once over. stick all the warning labels etc. then we'll fill in the G98 notification and send it off.

 

[brewdexta]

Looks like I'm getting about 600W and its well cloudy. I've just set up the phone app to monitor it. So about 12% capacity at the moment, which is why I went nearly up to the max kWp for the inverter in terms of the number/type of panels I installed.

 

[brewdexta]

I'm down in London for a couple of days, so can't see my home grown local power monitors (yet, I will soon), just the cloud based service from the inverter.

I must have done something right as I'm getting over 40% of the panels capacity, and it was a miserable wet day when I left home, I think it may have brightened up a little, not sure. Ignore the revenue bit, I'm not getting any for exporting but the portal didn't like it being set to zero so set it to 5p a unit.

Looking at the battery and grid details, as the battery had been in a box for a couple of months, it needed charging, the inverter did that from 15% to 65% SoC and exporting a little. But now the missus has plugged in the EV so solar and battery are charging that plus we are now importing from the grid.

Fascinating

 

[MoreWellie]

I forget which make of inverter you are using but I am curious to know if the figures from the inverter and/or the cloud based service marry up with what you see on your smart meter or even your generation meter assuming you have one

 

[brewdexta]

I'll be having a look when I get home from London on how the figures marry up with what data I currently have.

I have stats from the so called "smart" meter going into a time series database constantly.

I also have separate current sensors on the main incomer, the cable to the inverter and the cable to the barn. These supply current, real and apparent power plus power factor but I've yet to finish exporting the data into the time series database. I've been concentrating on getting the solar in and earning its keep but that should only take an hour or two.

I decided against a generation meter as I'm not requesting anything back for export.

I also have another project to talk to the inverter directly to gather stats, that may take a few more weeks. That will mean I can generate graphs with a direct comparison from the different data sources.

 

[brewdexta]

The inverter said I produced 7kWh yesterday. Not huge but the weather was only clear for an hour or so.

My own tools that are completely independent of the solar inverter show the following consumption from the grid,

From the screenshot below, the top graph shows total 24hr use of 5.76kWh, and my average daily use before solar and when we weren't charging the car was about 12kWh, so I think that shows the inverter is in the right ball park.

The second graph shows hourly import from the grid, you can see that during hours of sunlight, import from the grid is lower, not surprising really

The next screenshot shows two graphs, top is cumulative grid consumption over a day, the steeper the graph, the faster your importing. Its almost flat between hours of sunlight.

The final graph shows 5 minute granularity average usage. There aren't many peaks during the daylight hours as the battery smooths them out if its gone cloudy and the PCV can't keep up. Having just 2.4kWh of battery means that there is usually little left on a cloudy day to extend supply after dusk, but at this time of year I won't be able to charge more battery unless its a nice sunny day. I'll buy another 4.8kWh in the spring when it will be useful with longer days and the sun higher in the sky.

The above data comes directly from the supply meter.

I have an independent set of current sensors that I'm going to sort out next so I can shove the data into the same database.

 

[brewdexta]

Just looking at the current sensors before I start putting the data into the database. From the command line it writes a line every second, so here's 4 seconds output,

^Cpi@ecpi01:~ $ lcl-run
38400
11 5024.78 5100.35 21.72 234.78 0.985 -2459.91 2463.83 10.50 234.68 0.998 -7289.37 7318.88 31.17 234.80 0.996
11 5033.07 5107.72 21.74 234.99 0.985 -2486.52 2490.27 10.59 235.15 0.998 -7314.08 7343.65 31.23 235.15 0.996
11 5018.92 5093.25 21.68 234.89 0.985 -2486.15 2489.81 10.60 234.79 0.998 -7293.23 7322.68 31.19 234.79 0.996
11 5047.53 5122.61 21.80 235.03 0.985 -2460.96 2464.78 10.49 235.02 0.998 -7290.63 7319.38 31.14 235.02 0.996
^Cpi@ecpi01:~

The first column is just a device ID and can be ignored

The next 5 columns are from the grid apparent power, real power, current, voltage and power factor
The next 5 is from the Solar, looks like I have the sensor in the wrong way but all it does is add a minus sign
The next 5 is current going to the barn where I've plugged in the EV, sensor also in the wrong way, I'll sort that later.

So roughly 21 amps from the grid and 10 from the Solar is charging the car. Not for long though, the Solar battery was about 80% charged, not for long

 

[minimutly]

3.8kW will net you 4000 kWh a year in a good year. Your target I guess is to capture and use it all. Looking forward to your posts.

 

[brewdexta]

3.8kW will net you 4000 kWh a year in a good year. Your target I guess is to capture and use it all. Looking forward to your posts.

Yes, export as little as possible is the strategy

I've got the current sensor data going into the time series database, I was a bit rusty but only took about 30 minutes.

I put a Gatemate lock on the solar shed door earlier. I was cursing because the lock barrel diameter was a funny size, just over an inch. I eventually found an old hole saw that did the trick. Then going through the box for the screws, I found the 27mm flat wood bit that comes with it. doh!

Next task is building the little box of gubbins that will extract stats direct from the inverter. The Spark was coming around today to finish off the commissioning but he's got some kind of lurgyfrom his kids so it will be next week now.

 

[brewdexta]

As the weather is carp and I'm putting off going outside to jet wash the lethal moss from stone flags and steps, I did a bit of tinkering with the data from the current sensors that has been going into the database overnight. Here's a quick graph, took longer than I thought as I hit a bug in Grafana that stopped me renaming the data series to something intuitive, I had to resort to SQL to rename them in the end.

The big spike on the left is when I put the EV on charge last night, it was about 75% full. The charger hangs off the barn so both these sensors show the spike. Not much coming from solar today, its overcast and mizzling.

What it does show is that the barn is pulling a constant 2 amps, so over 500w. There is a freezer in there, plus my techies stuff, NAS, CCTV etc. but I wouldn't have thought that it would amount to that so now I have the right tool I can turn off a few MCB in the barn consumer unit and find out what's the main consumer. I'll mess about with real, apparent, power factor and all that malarkey later.

 

[rtcosic]

I put a Gatemate lock on the solar shed door earlier. I was cursing because the lock barrel diameter was a funny size, just over an inch. I eventually found an old hole saw that did the trick. Then going through the box for the screws, I found the 27mm flat wood bit that comes with it. doh!

Too late now, but those Gatemates don't accept a standard Euro cylinder. I always fit a set of keyed alike cylinders so I only need to carry one key for the whole property.
I had to replace the Gatemate with an alternative design that does take Eurocylinders.

No 2 son has just had his Solar PV installation completed. We have already started competing over who is harvesting more electrons. No 1 son can't play as he hasn't given us access to his live data.

Competitive? Us? Never. Admittedly Monopoly is a blood sport in our household and SWMBO has banned its use.

 

[minimutly]

This years total (according to Fronius inverter), 3970kWhs. Will I scrape 4000, my best ever year?
Not bad for a 12 yr old single string system.

 

[fizzy]

This years total (according to Fronius inverter), 3970kWhs. Will I scrape 4000, my best ever year?
Not bad for a 12 yr old single string system.

With the current price you are definitely winning!

 

[Gareth J]

Happy with the apparent lack of degradation with mine. Obviously it's dependant on weather too but, considering they have never been cleaned, seems ok.


Not quite up to brewdexta's level of datalogging though. I can't even manage to take an in focus picture!

 

[minimutly]

Happy with the apparent lack of degradation with mine. Obviously it's dependant on weather too but, considering they have never been cleaned, seems ok.
View attachment 376775

Not quite up to brewdexta's level of datalogging though. I can't even manage to take an in focus picture!

You’ve made me slightly jealous with those Numbers, average 300kWhs more than my install. That’s £150 a year for me...

 

[Gareth J]

You’ve made me slightly jealous with those Numbers, average 300kWhs more than my install. That’s £150 a year for me...

With that rate, you shouldn't be. I can't remember FiT rate, but it's not 50p!