Solar panels and battery - any real world recommendations?

I don't think batteries were really much of a thing back then, even in 2015 they were very expensive and didn't make financial sense.

I think most DIY'ers back in 2012 used lead acid batteries.
 
I have been considering panels for years, my dad had them many years ago, but I knew I wanted batteries and they needed to be big ‘enough’…..for me recently it all felt right. In short I could get what I wanted for the price I wanted to pay……for me payback will be 8ish years but you can do way better
 
doodah said:
What does it do that the AI nonsense on some systems can't (I turned it off on our Sigenergy as it burns through battery cycles more quickly)? HA is on my to do list for home improvements :)
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Predbat is basically a highly configurable tool for your solar and battery array, rather than a hidden AI.

What it does is runs purely on equations and logic to find the most cost-effective way to manage your battery. You point it to your octopus sensors (e.g. current import rates, export rates, solar forecast, battery soc etc....)

It'll also know when octopus special sessions are and put those into the daily planner for how to manage your solar and battery. In my case it'll also help heat up the water and UFH.


How it works on Home Assistant (not exhaustive list):

Inputs: It takes your historical house load data, your specific energy tariff rates, and solar forecasts from Solcast as I mentioned above.

The logic/maths: Every five minutes, it looks at the next 48 hours in 30 minute blocks. It works out the financial outcome of every possible charge and discharge scenario.

What it does: It picks the cheapest plan and tells your inverter what to do.

You can make it more aggressive to export more or very conservative to save your battery for evening use. You can really tweak it to your heart's desires. But once it's set up it's fire and forget. Though you can always override it if you want. Put it this way for March I'm already quids in for solar and payback.

The reason it avoids burning through unnecessary battery cycles is because you have full control over the parameters. You tell it your battery conversion loss rates. You can tweak and customise it to suit your needs as much as you want.

If cycling the battery costs more in energy losses than you would save on the tariff price difference, Predbat won't do it unless you've customised it or forced it to.

With a closed systems like Sigenergy, you just have to rely on their algorithms to get it right and you can't really modify it I don't think? I'm not sure as I have givenergy kit.

Anyway Predbat shows you its workings out on a dashboard and lets you tweak the variables to suit your exact setup.

I used to set up manual discharge and charge based on my tariff. Now it does it all for me based on all the variables and our usage. It really is fantastic bit of home automation.
 
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devil84 said:
Christ. Years . Wish I got this ages ago but assume the solar panels was not as efficient and battery size was lot smaller ten years ago?
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It's never too late. I only got my kit in 2022 but didn't realise there was a whole community here about it. Honestly it's worth it. Our DD has dropped from £250+ per month to £75 purely because of how much credit we get from march to October.

But it's not just about saving money it's also the fact that it's the right thing to do.
 
It’s also entirely possible to go negative on your bill.

I’m fully electric, heat pump, solar, batteries, EV, no gas, no ICE cars.

I keep a token £20 direct debit going but I’ve built up £720 in credit in the last 12 months. £300 was how much they paid me for my energy less why I bought from the grid, £240 was the direct debit and I’ve had a few referrals this year.

I don’t think I’ll be negative this year due to the rate changes and my milage is going to double to 20k.
 
Hi Gents
Just had a first quote through, would really appreciate some thoughts on it:

Aiko 475w All Black Panel x34
Sunsynk 16kW Hybrid Inverter x1
Fogstar Stackable 64.4kWh Total x4
Sunsynk Monitoring
Bird Barrier x34
IWA registration
MCS Certification
DNO Registration

Total Cost £23,600

Now first things first, they've messed up the number of panels because they've used an old out of date google maps/google earth screenshot of our roof before the extension, so they've only put 34 panels when they could probably put another 20 I reckon.

But I think the fogstar battery plan is sensible given we use 50-80kWh per 24hrs stretching up to 100 on car charging days. Not sure about SunSynk for the inverter, I've heard the brand before but don't know if it's any good.

Won't post the company name in case it's against the rules.

Cheers
 
Minato said:
Now first things first, they've messed up the number of panels because they've used an old out of date google maps/google earth screenshot of our roof before the extension, so they've only put 34 panels when they could probably put another 20 I reckon.
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you're better off getting this sorted first and getting the correct quote
 
My first thought is, that’s a lot of output, do you have a high energy usage? If not, the export limit may be a factor. If you put in for a 16kw inverter and they only allow 8, you’re going to have a lot of excess. Which is fine with the batteries and high usage eg ASHP.
 
tamzzy said:
you're better off getting this sorted first and getting the correct quote
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Fairs, although now having looked at the architectural diagrams myself that I've sent them, maybe I was overestimating slightly and it won't be that many extra panels. But I'm assuming an extra £1-2k at £100/panel.
 
how many sides of scaffolding do you need?

basically:
panels: £100 x 34 = £3400
inverter: £2300 ex VAT, so lets say £3500 after markup
batteries: £1k per 10kwh = £6500

scaffolding 3 sides: £800 per side = £2400
bird-proofing: £500
DNO stuff: £300

total cost exc profit: £16500
i guess with london pricing £23600 isn't too bad, but that's an extra 50% on top of the marked-up prices already :(
 
tamzzy said:
how many sides of scaffolding do you need?
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When we did the extension a couple of years ago and had all the scaffolding up (I know, I know, stupid not to do it then but budgets...), I think it cost us £8k. Since a lot of it is needed and it'll be on all 4 sides of the house I suppose. Although I guess they could do a bit, take it down and move it to another bit.

Mercenary Keyboard Warrior said:
Are you on 3 phase?
If not your butting up against the max for a single phase inverter
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Single phase.

Yeah, although I'm hoping the 16kW inverter will be enough, since it can then charge all 4x16kW batteries or 2x32kW batteries overnight. That'll get us all our daily usage on the battery most days, and stuff like car charging and night usage will be on the cheap rate at least. And anything from the panels will then be a bonus
 
Thats probably why they are not maxing panels then
Your going to be pretty much maxing the capability of your fuse anyway
Its about the rating for an 80amp but a bit short of a 100amp

They probably don't want to risk getting too close to the absolute wiring max so I am assuming your on a 100amp
 
Mercenary Keyboard Warrior said:
Thats probably why they are not maxing panels then
Your going to be pretty much maxing the capability of your fuse anyway
Its about the rating for an 80amp but a bit short of a 100amp

They probably don't want to risk getting too close to the absolute wiring max so I am assuming your on a 100amp
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yeah we're on 100amp

Before the inevitable questions of why do you need so much battery storage, no we're not growing weed, no the neighbours aren't stealing our leccy, and yes I've checked. Here's the data export from Octopus for Oct 24 to Present


 
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Any suggestions on in-roof panels ? Looking at getting a quote and they use GSE fixings so trying to get an idea of quality/price and if that matters?
 
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It seems to be the go to option. I have selected it for my install, but am 5-6 months away from that. From everything I have seen, it looks like the best product.
 
Minato said:
yeah we're on 100amp

Before the inevitable questions of why do you need so much battery storage, no we're not growing weed, no the neighbours aren't stealing our leccy, and yes I've checked. Here's the data export from Octopus for Oct 24 to Present


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Curious as to where you use so much?
 
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