Daily pv production

ELM327 · 09-05-2023 1:59pm

Getting a consistent 20-25 kWh per day now (8kWp SSE), car is charged by solar now too. Stopped load shifting a few weeks ago. (i've been on garden leave between jobs so able to monitor and optimize usage!

DrPhilG · 09-05-2023 3:19pm

Yeah I'm sitting around 22kWh a day on average, disappointing actually for May.

society4 · 09-05-2023 3:33pm

can I just enquire I too have an ev and plan on getting solar panels…..Am I right in thinking you can charge on a sunny day and get about 100km from the solar if you charge the car for 4 hours… .I wouldn’t mind having the option to heat the hot water cylinder too….would 8 panels be enough and do I need a battery…would it cost bout 13k or so…..

ECO_Mental · 09-05-2023 4:02pm

https://www.boards.ie/discussion/comment/120575069#Comment_120575069

8 Panels would give you say 3.2 kWp, On a sunny clear day you will push out 3.2 kW for about only 2 hours maybe, but you will have base load etc running in the background so you might only have 3 kW pushing into the car. So two hours will put 6 kWh into the car battery which is under 10% of most car batteries. I dont know what a 3.2 kWp system will push out on a sunny day depends on a lot of numbers.

You also need to consider the car wont charge at less than 1.2 kW so you will need to probably import the balance of that if you are not producing enough.

BASICLALY what I'm try to say is put up as many panels as you can physically fit on your roof.... An EV will soak up everything you can throw at it...

If you look at my production yesterday which was overcast all day my PV baseline (red line on the graph) never went below 1kW (orange straight line) I have a 6.1 kWp system. If I had the car plugged in yesterday I would only have only ever have to imported about 200watts to charge the car. A 3.2kWp system baseline might only be 500watts...

Also no real need for battery the payback isnt there (but I would love one...😏) although with the 0% VAT no harm in look at it.

society4 · 09-05-2023 4:36pm

Thanks that’s very helpful

DC999 · 09-05-2023 5:00pm

https://www.boards.ie/discussion/comment/120575069#Comment_120575069

Adding to what Eco says above, a lot of us with solar and a smart car charger (that 'knows' there is solar excess) charge our cars largely from solar for ~6 months a year. Which is just amazing. Free 'motion lotion'!!

Car needs to be in the driveway when it's sunny of course. And a Zappi is the traditional smart charger used. If you have a non smart car charger, you'll need to replace it. But can sell the existing one 2nd hand. Huge number of new EV and PHEV owners these days.

8 panels won't be enough. I've 16 (all roof can take) and could use more to feed into the car if I had space. Bigger is deffo better.

If you've more Qs, you're probably better taking the thread here to get more info: Solar for Dummies. - Page 56 — boards.ie - Now Ye're Talkin'

HotSwap · 09-05-2023 6:35pm

https://www.boards.ie/discussion/comment/120575473#Comment_120575473

Worth remembering if you export during the day; you can buy those units back at night for half the price. So it’s not essential to have the car in the drive all the time.

but bigger is better if you have the budget. 18 panels here with no EV and I’m basically self sufficient. If I add in an EV or a heat pump I’ll be back to paying bills.

micks_address · 09-05-2023 6:40pm

yeah if you are on a night boost smart meter tarrif it pays to charge/import everything between 2am and 4am (ei) and export during the day.. that said ill still top up the car if i have a lot of export as im going to hit the 200 euro cap of tax free export soon.. not sure if anyone will care.. what is the tax on fit? if i self declare end of the year? i know others are treating it as discount as opposed to income.. be curious how that plays out

HotSwap · 09-05-2023 6:56pm

https://www.boards.ie/discussion/comment/120575835#Comment_120575835

Can I ask EI to take my account credit and transfer it to my bank account? Maybe I’ll use it to buy some heating oil :) if I’m paying tax on it I might as well spend it how I like.

society4 · 09-05-2023 7:01pm

Thanks all..food for thought….I think 10 is max I can fit on roof..

micks_address · 09-05-2023 7:11pm

https://www.boards.ie/discussion/comment/120575904#Comment_120575904

i guess if you switch provider then they have to cut you a cheque

the_amazing_raisin · 09-05-2023 8:18pm

https://www.boards.ie/discussion/comment/120575069#Comment_120575069

Probably not 100km per day

You won't be charging at the full 7kW unless you've a field full of solar panels nearby

Most days at the moment I'm seeing 1.5-3kW on and off in the afternoon

You should check out the thread below on some solar charging experiences with EVs

https://www.boards.ie/discussion/2058294549/im-driving-on-sunshine-whooah

Recently I got something like 550km of free driving for almost 6 weeks. I haven't charged from the grid since the start of May and am aiming not to use the grid for the rest of the month for the car

A lot depends on your habits, you need to be home most of the time with the car plugged in. For example I was out today and "lost" 13 kWh to the grid 😬

Really could have used them too, I need to drive again tomorrow so I'm getting worried I'll need an overnight charge

DC999 · 09-05-2023 9:24pm

https://www.boards.ie/discussion/comment/120501357#Comment_120501357

Hey, would you mind sending me the link to the met eireann forecast python script? Been dodging it so far but am looking to mess with python now.

the_amazing_raisin · 09-05-2023 10:04pm

https://www.boards.ie/discussion/comment/120576775#Comment_120576775

Welcome to the dark side 😉

ELM327 · 11-05-2023 2:59pm

Generated 2kWh today so far. Power cut at 930am. House battery charged to full last night as were my 12v UPS batteries.

Working away here on backup power. Panels went at the same time the mains did. Really need to sort this out, I hate seeing lost power when the mains is out yet I have nearly 30kWh stored at the house excluding the car

Delboy5 · 12-05-2023 9:32am

Met.ie predicting over 30kWh for me today and of course ESB have scheduled a power outage for half the day!!!!!

DC999 · 12-05-2023 9:37am

https://www.boards.ie/discussion/comment/120586378#Comment_120586378

You’re not in D12 anyways, can’t see the sun today with the clouds 😊

bullit_dodger · 12-05-2023 12:13pm

Or D16 for that matters. Same here with the clouds although from....

Ireland Visible - Met Éireann - The Irish Meteorological Service

Looks like it might clear up. Tomorrow though by all accounts will be the best of the year so far....see 35Kwh forecasted (33Kwh today for comparison) add in the shed and I might get to the mystical 50Kwh!

SD_DRACULA · 12-05-2023 1:03pm

Yeah 40+ kwh estimated for today by solcast, met, forecast.solar, the F it will with these clouds...

Mr Q · 12-05-2023 1:09pm

The weather has been a bit crazy this week between thick dark clouds and bright sun. I'm on over 18kWh today and the sky must be very clear at home. The problem for me is I'm not there. And my Sofar keeps thinking my battery is full when it's not.

bullit_dodger · 12-05-2023 2:11pm

Interestingly enough as a side point about clouds and bright sunshine. I got ....

7.12Kw yesterday. This isn't bad considering it's a 5Kw inverter!

To be fair, it didn't last long at this level and reverted back to a more regular 5.3kw within a minute or two.

HotSwap · 12-05-2023 3:24pm

Tullamore: must be very sporadic cloud. Very choppy graph

Doing a nice job avoiding clipping at 6kwh due to keeping the battery below 100% until 15:00.

keith_d99 · 12-05-2023 4:42pm

https://www.boards.ie/discussion/comment/120587886#Comment_120587886

A couple of questions on your set-up (as I will be buying something similar in the next few weeks)

During the summer months do you still need to charge the battery off the EV rate during the night - I would have thought that would only be necessary in winter months?
The battery usage during the day. Is that heavy usage/EV charging pulling from both panels and battery simultaneously? Does the invertor pull from the battery when it can't get enough from your panels?

pollocks · 14-05-2023 9:14am

Day 2 of production and we hit 55.2kw yesterday. Its a bit addictive watching the app and trying to burn some of the excess generated.

Ill have to work out if we should stick to the day/night meter or change out for the smart meter and get the full benefit from the FIT rate.

ECO_Mental · 14-05-2023 9:49am

https://www.boards.ie/discussion/comment/120594977#Comment_120594977

Looks like you have a decent system and you will be exporting a lot unless you have a car and/or battery as well. I reckon a smart meter is worth it I lost €300+ last year in lost FIT payments and another hundred or two in shifting the EV charging to boost rates. But do the sums...I have D/N meter and looking to get a smart meter but it's taking months and months (no idea when i will get one) as ESBN are concentrating on retrofitting the 24h meters first.

HotSwap · 14-05-2023 3:53pm

https://www.boards.ie/discussion/comment/120588215#Comment_120588215

I don’t NEED to charge the battery at night in summer; but I do it anyway. I have it set to charge between 2-4am when the cost per kWh is .12 cent. I would have had the same understanding as yourself before I really thought about it; but here is my logic:

The units only cost .12 cent each between 2-4 am; so if I fill my battery at that time; I will have the highest possible SOC when the panels start producing power. As you can see from the graph it went down to 90% before the panels were generating enough to support the house (at which point the excess is charging the battery).

I then have an automation waiting to trigger when the SOC hits 95%; at which point I transition the system from using excess PV power to charge the battery; to using the excess to feed the grid. The system stays in this mode until 15:00.

So my thinking is; as I’m getting .21 cent for each kWh that I export; which is essentially double what I can buy the units for between 2-4 am. I might as well fill the battery up at night so that I will start exporting as quickly as possible each day. If I buy in 6kwh in any given night; I will only need to export 3kwh to cover the cost of that import. So it’s just maxing out the FIT. In a way I think it’s also better for the common good; as I’m using the grid at night when it’s under used; and then I’m exporting power for my neighbours to use during the morning peak (they still pay full price; but it’s lowering their demand on the grid at these times).

because the battery is in this “feed to grid mode” any loads that exceed what the PV can support are taken from the battery and not recharged; as excess is explicitly told to go to the grid not the battery; but this is intentional; when we get to 11am-1pm the panels 7.5kwp can be generating more than the inverter can output (6kwh) BUT the trick here is that the inverter can output 6kwh AC to the house / grid; AND also put the excess directly into the battery; so I see situations where 6 is going to the home / grid and 1.5 is going into the battery. This didn’t happen that much on this specific day; as the panels were hotter (and generate less) but it happens a lot and it’s worth doing.

gotta go out… will respond more when I get back.

HotSwap · 14-05-2023 6:08pm

Wasn’t a lot more to add; you have it; when the house is pulling more than the panels are generating its coming from the battery.

And with this inverter / battery combo I can pull and push 5kWh to the battery to meet that demand.

What it can’t do is output more than 6kwh; so if the panels are generating 6; and the house needs 7 (this has never happened - it might if you had an electric shower; but we don’t) that extra 1 will need to come from the grid even though you have a full battery.

for most inverter battery combos that installers use the discharge and charge rates of the battery can be around the 3kwh mark. So ask about this.

hope this helps.

HotSwap · 14-05-2023 6:32pm

https://www.boards.ie/discussion/comment/120594977#Comment_120594977

Look at the standing charges also. But I’d say just go with the smart meter; as that’s what you’re going to end up with eventually anyway. Unless you have some way of using that electricity locally and getting paid for it.

how many panels do you have at least 20?

keith_d99 · 14-05-2023 9:15pm

Yep very useful info in both posts - thanks for taking the time to write them up!

pollocks · 15-05-2023 9:28am

https://www.boards.ie/discussion/comment/120596834#Comment_120596834

Yeah 20 panel 8.3kw array and 5kw battery, we do have people at home during the week to eat into some of it but no EV currently, although I'm sure one of the cars will eventually become one though!!. I am thinking the smart meter is the better option to build up credit for the winter months when the heat pump roars back into life.

Daily pv production

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