Soldato
odd is fine it just must not be a prime number 
Solar panels and battery - any real world reccomendations?
- Thread starter GinG
- Start date
Soldato
Is there any 101 articles that explain fully about solar panels and benefits of using batteries or not?
Soldato
What do you want to know.
There is plenty of knowledge round here.
Both the techs have pros and cons and considerations.
They work well in isolation but add to each other to some extent.
Your own usage etc all feed into whats best or whats reasonable for you.
Associate
As above it depends on your situation. However I'd say the biggest benefit of batteries is using more of what you generate and being able to charge cheaply from the grid when there is no solar. Not to mention the ability to discharge to grid during saving sessions which can be quite lucrative (£2.25 or £4 per kWh this winter so far).
In general, now SEG (export) rates are better, the benefits aren't as large, as you can essentially use that to build up credit to offset your usage when you dont have a battery. In that situation you are at the mercy of the energy suppliers who could reduce or pull their best tariffs at will though.
They are coming down in price, so the decision for is becoming easier.
To add to the above, understand your usage.
Know what your average daily use is in summer and in winter. What your max draw is and at what time?
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Associate
Personally, I'd say having battery storage is more beneficial then having panels imho.
I've been kinda struggling with the 5kw limitation when cooking etc. so wanted to look into upgrading the inverter.
Instead of getting rid of the 5kw inverter and swapping it for an 8kw, would it be possible/make more sense to install a second 5kw inverter in parallel as master and slave?
I've been kinda struggling with the 5kw limitation when cooking etc. so wanted to look into upgrading the inverter.
Instead of getting rid of the 5kw inverter and swapping it for an 8kw, would it be possible/make more sense to install a second 5kw inverter in parallel as master and slave?
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Soldato
Split the strings, across the two and master slave is possible, less efficient than a single though and more complicated to control. I guess taking the 8.8kW as suggested would have been a good move, shame really.
Associate
I'll be able to tell you soon, as my NW facing array being installed on Weds will be off a second 3.6kW non-hybrid inverter running with my existing 5kW hybrid and connected via a CT clamp. I looked into a single larger hybrid inverter but decided against it as I can charge my existing batteries fine in the three hour window and it would have cost much more. In theory when it's sunny on the new array I could use or export that as well as the 5kW max on the existing inverter.
Associate
Yeah, I should have gotten the larger inverter..Split the strings, across the two and master slave is possible, less efficient than a single though and more complicated to control. I guess taking the 8.8kW as suggested would have been a good move, shame really.
I didn't have any peak usage data to go off though until I had this system in place.
The smart meters were only installed shortly before the solar and my gas meter still isn't communicating..
When I enquired the other day regarding upgrading the inverter, Myenergy were saying something about there being a power mismatch with using an 8kw inverter with my 6.45 array. They said they would have to look into it and get back to me, so I don't know what my options are at this stage.
They also say I can't fit more panels unless I get someone else to remove/change the vents and they probably wouldn't work very well being so low on the roof.
I think they've sent me the wrong data sheet for my battery too. The data sheet says SUN-BATT-5.12-BYD 100Ah Wall with an 80% DOD, but searching says that model is discontinued and replaced by the L5.1 with a 90% DOD which look more like my batteries.
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Soldato
I wouldn't worry too much about max draw, although its worth considering.
Eg if you have a high max draw for long periods your going to have a high usage in total, and as such your either going to need to install a mega system, or your going to import anyway.
Do myenergy have a design tool? I found the solax one myself and was able to go in and play around with designing/modifying my system that way.
I think the main considerations are (ignoring the technical ones like roof facing, shading etc)
For batteries the largest benefit comes from TOU tariffs, with either cheap import times and/or export opportunities, I think without these batteries even for harvesting excess from solar the ROI is horrible
For solar its a sensible size array (and sensible is potentially a higher value if you have batteries), considering when you will generate most energy and if you can use that if you dont have batteries
IE East is morning till lunchtime mainly, South is mid morning to mid afternoon mainly, west is lunchtime to afternoon mainly. If your out when you peak will hit the batteries start to become more critical.
Things change.
In just over a year since I got my system, so vs what I was playing with in calculators, prices have dropped a bit, they could always do so more or go back up.
Panels have gained slightly in output, batteries seem basically unchanged.
TOU tariffs have changed with the launch of flux. But really the only beneficial supplier is Octopus, if something was to happen to them...
Eg if you have a high max draw for long periods your going to have a high usage in total, and as such your either going to need to install a mega system, or your going to import anyway.
Do myenergy have a design tool? I found the solax one myself and was able to go in and play around with designing/modifying my system that way.
I think the main considerations are (ignoring the technical ones like roof facing, shading etc)
For batteries the largest benefit comes from TOU tariffs, with either cheap import times and/or export opportunities, I think without these batteries even for harvesting excess from solar the ROI is horrible
For solar its a sensible size array (and sensible is potentially a higher value if you have batteries), considering when you will generate most energy and if you can use that if you dont have batteries
IE East is morning till lunchtime mainly, South is mid morning to mid afternoon mainly, west is lunchtime to afternoon mainly. If your out when you peak will hit the batteries start to become more critical.
Things change.
In just over a year since I got my system, so vs what I was playing with in calculators, prices have dropped a bit, they could always do so more or go back up.
Panels have gained slightly in output, batteries seem basically unchanged.
TOU tariffs have changed with the launch of flux. But really the only beneficial supplier is Octopus, if something was to happen to them...
My winter strategy is fairly straightforward, charge the battery to 100% each night on Octopus IO at 7.5p and not worry about the solar so much.
Summer is where I'm not sure whether to go flux or stay on OI. Having an EV throws a spanner into the work with flux and the short and high night rate makes it not so attractive and I think I'll probably be better off staying on OI.
If I stay on IO, I'll probably still charge the battery to full nightly as the export rate (15p) and just export all the excess power I generate.
Summer is where I'm not sure whether to go flux or stay on OI. Having an EV throws a spanner into the work with flux and the short and high night rate makes it not so attractive and I think I'll probably be better off staying on OI.
If I stay on IO, I'll probably still charge the battery to full nightly as the export rate (15p) and just export all the excess power I generate.
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Soldato
i thought io had the same export limitation as go, ie the 8p export one, are you sure you can have the 15p one?
According to the peeps on the Tesla forums, I can get the 15p rate but those on 'regular' Go can only get the 8p rate.
Edit: I'm also temped by agile but I might wait until I can see what the system is really capable of first.
EDIT2: The website only singles out Octopus Go as not being eligible.
octopus.energy
"We’re offering customers on Intelligent Octopus the standard Outgoing Fixed price of 15p/kWh because the grid flexibility their smart charging unlocks means greater cost savings."
octopus.energy
Edit: I'm also temped by agile but I might wait until I can see what the system is really capable of first.
EDIT2: The website only singles out Octopus Go as not being eligible.
Outgoing Octopus
The UK's most awarded energy supplier. We're doing energy better - for you and the environment.
octopus.energy
"We’re offering customers on Intelligent Octopus the standard Outgoing Fixed price of 15p/kWh because the grid flexibility their smart charging unlocks means greater cost savings."
FAQs about Outgoing Octopus
Get acquainted with Outgoing Octopus, our one of a kind smart export tariff
octopus.energy
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Soldato
Intelligent does give 15p/export as well, Go does not.
Would current solar PV owners recommend it?
Seriously considering installing an array + battery for my home.
Are jinko and sunsynk good brands?
I've got a quote for 8x 440w jinko panels, 3.6 KW sunsynk hybrid inverter and a sunsynk 5kwh battery for £7k all inclusive - good deal?
Seriously considering installing an array + battery for my home.
Are jinko and sunsynk good brands?
I've got a quote for 8x 440w jinko panels, 3.6 KW sunsynk hybrid inverter and a sunsynk 5kwh battery for £7k all inclusive - good deal?
Soldato
IMO Solar + Battery is a no brainer now, especially if you can get a decent sized array, and you aren't only chasing payback times. As for the quote £7k is Ok, the battery is small but I guess you should look at your power use and max load, given your job you probably aren't really home much I'd imagine?
Yeah that's correct, estimating a yearly use of 2000kwh, 4000kwh production and a 6 year ROI including of SEG @16p/kwh.
80% grid-free independence or whatever they call it
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Soldato
Key thing to note is panels and inverters aren't expensive any more, it is the one-off install costs, so put as much up as you can afford, especially now as it is zero rated for VAT - So if you have room, and get get the export going to 16 panels and a 5-6kW inverter will shorten the payback if you are exporting most of it. Also flip flopping between tariffs can work, e.g. Flux and IO, or Flux, Tracker/Agile.
Soldato
Not sure on that, our gas and electric was minus £406 last year (the whole year), and the additional system and batteries were only connected up late February, and due to delays with non-working smart meters we didn't start getting paid for export until April.
My first array, installed in December 2015 paid for itself in 2021/22.
Would I recommend it, absolutely, the more panels the better, and definitely a bigger battery and inverter.