Solar panels

[mdaw]

Hi all,

When I hopefully get moved in a few weeks I've been thinking about getting solar panels and a solar battery.
My electric usage isn't particularly high at around 2500kwh per year. I think from things I've seen I'd only need around a 3.5 kw system to cover this.
My roof at the rear will be south to South west facing so it will get a good amount of sun/UV over the day and also being in Sussex we do get a bit more than some parts of the country.
My thinking is I will probably get the biggest KW system I can get and if I have excess, use it to get SEG payment but without depleting the battery as that increases degredation believe. I want a battery as my wife and son are primarily in during evenings so I'd like the energy stored up for evening use as when I'm at home during the day as I do shift work I don't use much electric.

From what I can guesstimate using Google earth etc. I think the roof will be around 5.5m wide and about 4m high. That could allow me a 3.7-4KW system using high end panels.

Can anyone give me their experience with a system like this and how good it is during winter? Also how effective is just having solar panels during the winter?

 

[Unseul]

We have 4.5kw of panels, split over a south and a west facing roof, on a 3.6kw inverter. In one of the sunniest places in the UK though. Produced a bit over 4kwh of electricity in the past year (higher than the estimate, by a couple of hundred). Do not have a battery, as it wasn't economical when they were installed, now however, I'd certainly consider one. We're on an old meter, so benefited from it spinning backwards, basically meaning every unit was effectively returning usage price, rather than SEG price (another reason why a battery wasn't important).

It's not great during winter unsurprisingly, you can easily only produce a couple of kwh on a bad day, or less on a terrible one. Even a battery isn't going to really help you there. However it's still something.

We're hoping to move house soon, and I'm planning to get it kitted out with solar (3.6kw inverter is the highest we can do unfortunately), a battery and an air source heat pump.

 

[Nikumba]

Look at the costs of a battery first vs the savings it will give you.

If you have smallish battery say a 4kw one and you fully charge it through the day, bearing in mind in winter you are less likely to fully charge it and discharge it in the evening then you are going to save yourself around 72p basically 4kw * unit cost (avg 18p) over 10 years of the battery life you are going to save at current prices £2,628 vs the cost of the battery install, the bigger the battery the less of a saving.

It is worth asking for quotes with and without a battery and get quotes as I am looking at this atm and have 10 or 12 quotes all ranging from just under £5K upto £12K

Look at the make and model of the panels, inverter, is all install costs involved such as scaffolding.

 

[Rroff]

Battery in the equation is generally more about convenience than saving money. You'll probably be looking at replacing the battery around the time you break even on the costs. The batteries I'm using (gel rather than li-ion) are rated for ~1000-1100 full cycles before capacity starts to drop, 12v ~100ah, cost about £150-160 each - do the maths heh.

 

[Kill_Phil]

I've started to look into solar too as no doubt we're all going to be shifting to a greater reliance on electric. How easy is it to add a battery to the system retrospectively?

 

[gpuerrilla]

Same plan for me. Recent self build. Wife wanted driveway and lane finished so the vat returns went on this. As we wont be moving to another house it seems a good addition with 3 youngsters the electric use will always be higher than small household.

 

[Tom_ed1987]

Unless you circumstances are very specific, i'd only go into this from the point of view of it being a hobby/interesting rather than something that will save you money, because it will do the exact opposite.
I have an east/west split 4kw array that came with the house. Output on a typical overcast winters day is near negligible - 200-400w from memory. Certainly nowhere near enough to meaningfully offset the running costs of an ASHP through winter for example.

 

[Doobedoo]

Don’t forget it’s not just about the solar energy you store, you can also use to store cheap off peak electric on a economy 7 tariff for winter months etc.

You really need at least an 8kw battery imo otherwise you’ll still be importing electricity a peak cost.

A couple of screenshots of mine running yesterday.

 

[Unseul]

With electricity prices as they are going solar is becoming more and more and obvious choice I'd say.

Battery is a bit more of a question.

 

[andy_mk3]

With electricity prices as they are going solar is becoming more and more and obvious choice I'd say.

Battery is a bit more of a question.

To me battery makes a lot of sense especially when paired with an energy tariff that let's you charge them up for a very low cost overnight to top up what solar hasn't been able to do. They're still quite expensive though, but as with anything the price will come down and make it a more viable option.

 

[bobuk]

We've had solar panels for a few years now, get roughly £6-700 a year back for them, our electric bill went down approx. £30 a month, don't know what the going rate for produced electric is now, we get around 0.16p a unit, on a good day it produces £10-11.00, the last time I looked it wasn't worth putting in battery's.

 

[Unseul]

To me battery makes a lot of sense especially when paired with an energy tariff that let's you charge them up for a very low cost overnight to top up what solar hasn't been able to do. They're still quite expensive though, but as with anything the price will come down and make it a more viable option.

Yep, right now batteries do seem to make more sense, a year ago they didn't. Prices of batteries have come down, and cost of electricity has gone up.

 

[mdaw]

During the brighter/longer days I would be fairly confident my usual daily needs would be fairy well covered but my main concern is winter. Days are short so how much would my battery be charged by the panels? 200-400w does not sound a lot as mentioned above, although that would be a different setup. Other factors will make a difference I know for example which panels are actually installed i.e LG or sunpower (not saying others aren't good) vs some that are not so well rated. When it comes to inverters I've not done any research on those. Are there any particular brands to avoid or things I should look out for when speaking with a installer?
With the solar battery if you can get cheap off peak rates to charge it, then maybe that is the way forward for the winter. Can you get these deals when on a smart meter? I'm not sure if my next property is on one or not. I'm currently on a smart meter where I am now.
Looking at that my highest electric usage has been 169kwh in the last four months. Lowest was 147. On average I'd say 155kwh per month. I have no idea if that could be covered in autumn or winter.

 

[Doobedoo]

Yep, right now batteries do seem to make more sense, a year ago they didn't. Prices of batteries have come down, and cost of electricity has gone up.

Have they? I doubt you could buy my battery for less than what I paid for it 2 years ago. But electricity has defiantly gone up and will continue to do so.

 

[Unseul]

Have they? I doubt you could buy my battery for less than what I paid for it 2 years ago. But electricity has defiantly gone up and will continue to do so.

You couldn't get an 8.2kwh battery for £2.5k last year (at least not that I found, or not building it yourself).

 

[Doobedoo]

You couldn't get an 8.2kwh battery for £2.5k last year (at least not that I found, or not building it yourself).

Pylontech would be your best bet but it’s what people was saying back when I brought mine, that prices are likely to go down over the next few years but that was pre pandemic. Realistically speaking most of the worlds battery supply will likely be taken up by electric vehicles, so until supply out performs demand I doubt we’ll see much of a drop in pricing.

 

[Unseul]

Pylontech would be your best bet but it’s what people was saying back when I brought mine, that prices are likely to go down over the next few years but that was pre pandemic. Realistically speaking most of the worlds battery supply will likely be taken up by electric vehicles, so until supply out performs demand I doubt we’ll see much of a drop in pricing.

Just a quick look on my phone and i can't see any pylontech as big as 8.2kwh nor cheap as £2.5k for the equivalent. What have you got and how much was it?

 

[Doobedoo]

Just a quick look on my phone and i can't see any pylontech as big as 8.2kwh nor cheap as £2.5k for the equivalent. What have you got and how much was it?

I have the Powervault as per the pics I posted.

Perhaps you should link other people to what your finding. £2500 is not a bad price.

 

[Unseul]

I have the Powervault as per the pics I posted.

Perhaps you should link other people to what your finding. £2500 is not a bad price.

Thought it already was, must have been in the other thread that someone said they had the givenergy 8.2kwh. You can find it from a couple of stores for that price.

 

[Doobedoo]

Thought it already was, must have been in the other thread that someone said they had the givenergy 8.2kwh. You can find it from a couple of stores for that price.

That’s a great price people shouldn’t really have much of an excuse not to have one. Problem is people want it either for free or they want to profit from it.