Solar for Beginners [ask your questions here]

My 2 cents here;

System size - Get the biggest system installed that you can. I had quotes for as low as 6 panels, and went with an installer that quoted me 14 panels, but with a view to installing more on the day if there was room for them. In the end they were able to install 17 panels totalling 5.78kWp. In sunny days even in winter I'm producing about 3kWh in a good day, and often find myself turning on the washing machine or dishwasher to prevent feeding unused production up to the grid. (as I type this at 10:47am I'm currently generating 0.660kW and the house is only consuming 0.267kW (both home based with 3-4 computers running, so the rest is going back into the battery (currently at 81%)). 2-3 more panels might only cost you an extra few hundred euro at time of install, but to get someone to install those 2-3 panels a few years down the line might cost multiples of that initial outlay. My system only went live at the end of October, and since then I've found myself plugging in my EV to charge a few times as the battery was full and I had literally nowhere else to put the electricity. I need to get a Zappi car charger as the one I currently have is dumb so I've to manually start/stop charging and adjust charging current. I envisage that for about 5-6 months of the summer I won't need to charge the car off the grid at all unless going for a long drive at the weekend, but even then it won't need much.. I reckon I could put 10-15kWh per day into the car and only use maybe 5-10kWh of it so by the end of teh week the car should be fairly full.

Battery - In my case I went with a 5kWh battery, and from about November 1st, switched it to charge during the cheaper night rate. I find on most days the battery will last up until about 8-9pm at night, which means it covers the vast majority of that days usage in conjunction with solar PV production. Night rate ends at 8am, and the battery then supplies the house until the solar ramps up and takes over at about 10-11am and then starts topping the battery back up when production goes above house demand (it'll have gone down to about 70-85% by this stage). When I see the battery hitting 90-95% I'll turn on a washing load or a dishwasher (have already done this about 7-8 times so far this year).

Regarding the monitoring;

My Installer installed a WiFi dongle that simply plugs into the inverter and then connects to your home network. The app(s) then connect to your inverter through their cloud services so you can always see what the system is doing. I dont think it shows live data, but rather a snapshot taken every 5 minutes of what the system is doing. You don’t need to be on your home network to see this data either, I.e. out and about.

heres what my system is doing right now via the SolisCloud app;

Is this not the opposite of sustainability - needless consumption rather than feeding clean energy into the grid?

the opposite of sustainability would be to be so mean as to turn on your electric lawn mower and let it idle in the driveway just to avoid sharing an extra leccy.

As many as the installers can fit.

Don't over think it. Its very easy to fall down a rabbit hole on Solar and believe me I did.

Talk to a few installers and take it from there

The max as far as I know is 8kw.

I believe that there's a little headroom built into them too, they can take 640-650v typically, but not "all" the time. Like a spike up there for a few minutes won't blow them, so if your sub 450v, you should be able to add 2x safely enough. (They are about 38-40v each)

But sure you have 24x panels - you've loads :-)

You are my inspiration.

I'd say 13-14 panels would be about the max on 1 string with a small buffer. Depends on what the nominal voltage output of the panels as well as the inverter. The web is your friend there.

Usually (not always) the limit is a max voltage "per string" issue. As Mr Q say above that also depends on the inverter, but virtually all of them are in about 600V. So with it being (approx) 40V per panel, your looking at roughly 15 panels per string. If you had 370w panels, that would equate to about 11kw in panels, assuming you split the 30 panels equally between strings.

Note: While you could probably safely do that, just because you can do it, wouldn't equate to that you should do it :-) You'd be wasting a lot of production with that config, as your inverter will only pull down 6Kw, even though you paid for 11Kw in panels, so a bit of a waste.

That looks cool. How many square meters is that?

Are they facing south?

Thanks JimmyVik. About 40 sqm and all facing south, slightly ssw (200°) to be exact.

Thanks mate - I thought that was the case alright, but good to have it confirmed.

Oh I know. I have the microinverter right here. In fact I have two of them 😁

10,058kWh used last year, and I'd consider that average...

~5,000kWh would be on the low side...

I'm talking more about what the average household in Ireland is, not so much about you or me Andy.

What are Average Gas & Electricity Bills in Ireland? (selectra.ie)

Specifically..

The Commission for Regulation of Utilities (the CRU) is tasked with monitoring and collating information from Irish electricity and gas providers. According to the CRU, the average annual usage of electricity for an Irish household is 4,200 kWh.

Plugging 6Kwp with an azimuth of 0 (south facing) yields this as the expected generation.

These are estimates, but they are generally (reasonably) accurate +/- 10%

What he mentions about optimizers is correct. If one (or more) panels have shading on them it drags down the arrary to the yield of that one panel, so for every panel that has shading you should install an optimizer on.

Firm believer in "no stupid questions"

So, basically it's any significant shadow/shading which is falling on the panels in bright sunshine. Shading doesn't come into play on a cloudy day as the panels, while not generating as much as full sunshine, they are creating energy by "diffuse lighting".

A good example of shading would be panels next to say a chinney, and the chimney's outline would be covering some or all a panel. If the entire array was shaded by a tree (for example) then optimizers won't solve that. it's only really if one or more of the array is in shade, but there are others which are in full sunshine.

Bear in mind that as the sun changes through the year, there maybe times where an optimizers are helpful and other times of the year they are not needed, but if you can avoid them....do avoid them. They are €100 per panel and they can go defective. Pain in the ass if 7-8 years in you need to get someone out onto your roof - but they definetely do solve some problems in some scenarios and are worth installing.

Good video, though the 5 minute one might be better for the less technical.

I've been trying to explain about the shading to a few non-technical people - it just is so hard to get people to understand or 'believe' that it's this simple. I have one lad one who has an dish that is shading and he just wouldn't listen to me explaining he needs a couple of optimizers.

Incredibly expensive. Run away. You should be paying half that amount.

Before grant