Solar panels and battery - any real world reccomendations?

Freefaller said:
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Can anyone shed any light on the notification on the givenergy dashboard? I've looked through all the inverter pages and there's no obvious reason for it!
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I cant answer your question but I have similar with the number 1. I spent ages checking my settings, notifications and googling searching for answers and found none.

So hopefully someone can help!
 
Engram said:
I'd also welcome suggestions for a "fair" price for my quote.
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The difficulty is that a 4 east 4 west array is both relatively small and split across 2 roofs but you’ll effectively get charged the same for installation a someone else getting a much larger array. It’s basically the worst case scenario.

You’ll need scaffold on both sides that the going price seems to be £400-500 per side.

It’s always going to look like fairly bad value.

Take labour, it’s both a fixed cost and a variable cost. It doesn’t matter how big or small your installation is, you are always looking at a minimum of 2 roofers and a spark for the a day or two. The two roofers could probably install 16 panels on a south facing roof in the same time it takes them to install your 8.
 
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b0rn2sk8 said:
The difficulty is that a 4 east 4 west array is both relatively small and split across 2 roofs but you’ll effectively get charged the same for installation a someone else getting a much larger array. It’s basically the worst case scenario.

You’ll need scaffold on both sides that the going price seems to be £400-500 per side.

It’s always going to look like fairly bad value.

Take labour, it’s both a fixed cost and a variable cost. It doesn’t matter how big or small your installation is, you are always looking at a minimum of 2 roofers and a spark for the a day or two. The two roofers could probably install 16 panels on a south facing roof in the same time it takes them to install your 8.
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Yeah, that makes sense.
 
reef said:
Does anyone here have any north-west facing panels?

Our current array is 4.8kW and faces south-east, but on the opposite roof we could fit another 3.6-4kW of panels. It would be relatively cheap to do as everything else is in place, including a 5kW inverter which I doubt would be troubled too much as they are on opposite roofs. The only downside is we'd lose a little on the current SE array due to clipping, as the inverter is limited to 3.68kW per string. Its annoying but it would only really be an issue in the lighter half of the year but then the NW facing panels would make that up and a lot more. Plus we'd gain in the afternoon and evening, as at the moment it starts to drop off at 2pm onwards and we use a lot of power in the afternoon/evening, especially in summer (air con).

PVGIS suggests output would be around 60% of a southerly facing array, so with the extra clipping on the existing panels, would give around another 2000kWh per year perhaps (PVGIS suggests 2150kWh with 3.7kW on the NW roof).

Would it be worth it do you think?
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Ive been looking into overprovisioning so here are my thoughts

Check your inverter specifically. Mine allows 200% panelling, IE the Pw is listed as 10kw vs a 5kw inverter
But its also string limited to combined 7.5kw (so thats the real max output) and each string is limited to 16A, so depending on exact setup its quite possible to lose more or less than you expect.

What I would do is see if your manufacturer has a design site. Mine did I found (solax) and by using the tool and putting in the system I got two warnings, both related to "string 1" where i would combine the panels.
In effect it would limit my west facing array to around 250v (thats what 7 panels will produce) and 16A (I would combine 2x strings of 7 (serial) panels in parallel). 250v x 16A is 4000w. So in effect that string will cap to 4000w. It will clip to pull that down.
The actual panels would be 5.68kw so I get a yellow and an amber warning on their site.
The second "new" string would in effect be around 2.5kw of south facing panels but at a high angle (wall mounted) so I am practically never going to hit the combined 7.5kw. Maybe just about if the sun came out facing SW and the panels were really cold.

Many installers will tell you you cannot go that high on panels (mine suggested 12), but its sort of within spec.

Your issue is more that NW will never see the direct sun from around Sept to March. In summer the sun rises in the NE and sets in the NW. In winter it rises in the SE and sets in the SW. Its why when you look at production pure S panels are mush more efficient annually but not that much better peak summer.
 
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reef said:
Does anyone here have any north-west facing panels?

Our current array is 4.8kW and faces south-east, but on the opposite roof we could fit another 3.6-4kW of panels. It would be relatively cheap to do as everything else is in place, including a 5kW inverter which I doubt would be troubled too much as they are on opposite roofs. The only downside is we'd lose a little on the current SE array due to clipping, as the inverter is limited to 3.68kW per string. Its annoying but it would only really be an issue in the lighter half of the year but then the NW facing panels would make that up and a lot more. Plus we'd gain in the afternoon and evening, as at the moment it starts to drop off at 2pm onwards and we use a lot of power in the afternoon/evening, especially in summer (air con).

PVGIS suggests output would be around 60% of a southerly facing array, so with the extra clipping on the existing panels, would give around another 2000kWh per year perhaps (PVGIS suggests 2150kWh with 3.7kW on the NW roof).

Would it be worth it do you think?
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The problem is in winter when you need the actual production those panels will produce very little at all. I have similar situation with NE roof.
 
Mercenary Keyboard Warrior said:
Ive been looking into overprovisioning so here are my thoughts

Check your inverter specifically. Mine allows 200% panelling, IE the Pw is listed as 10kw vs a 5kw inverter
But its also string limited to combined 7.5kw (so thats the real max output) and each string is limited to 16A, so depending on exact setup its quite possible to lose more or less than you expect.

What I would do is see if your manufacturer has a design site. Mine did I found (solax) and by using the tool and putting in the system I got two warnings, both related to "string 1" where i would combine the panels.
In effect it would limit my west facing array to around 250v (thats what 7 panels will produce) and 16A (I would combine 2x strings of 7 (serial) panels in parallel). 250v x 16A is 4000w. So in effect that string will cap to 4000w. It will clip to pull that down.
The actual panels would be 5.68kw so I get a yellow and an amber warning on their site.
The second "new" string would in effect be around 2.5kw of south facing panels but at a high angle (wall mounted) so I am practically never going to hit the combined 7.5kw. Maybe just about if the sun came out facing SW and the panels were really cold.

Many installers will tell you you cannot go that high on panels (mine suggested 12), but its sort of within spec.

Your issue is more that NW will never see the direct sun from around Sept to March. In summer the sun rises in the NE and sets in the NW. In winter it rises in the SE and sets in the SW. Its why when you look at production pure S panels are mush more efficient annually but not that much better peak summer.
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I think Id definitely need to get a new inverter as even though its 5kW, it would then have 4.8kW (12 panels) on one string (SE facing) and 3.7kW (9 panels) on the other string (NW facing). They're opposite roofs so I don't think they'd trouble the 5kW limit much apart from perhaps when the sun is to the SW in high summer. It only allows 6500w of DC input with a max of 13.5A on each string, so I think 8.5kW of panels on it might give me issues. The voltage range is 80-550V and rated input voltage 360V but I know for a fact from other users it has a hard limit for each string of 3.65kW. I'm not too keen on losing 500-600w on the SE string in the summer half year which would eat into the already lesser gains from the NW facing part.

NW facing isn't ever going to be great (and pretty useless Oct-Feb), but the SE facing array dies off by 4pm and the extra output from 2-9pm in the summer half would be quite useful as we heavily use the air con then. Plus, we'd export more in the peak time on Flux when not using it.

The other option is we could probably just about squeeze on two more panels underneath our existing array on the SE-facing side. There's about 1350mm of space remaining so we could get two more on in a landscape orientation (1134mm). That would mean 5.6kW of panels in total with 7 panels (2.8kW) on each string (currently 7+5). That would be good for another 6-800kWh a year or so and would avoid the inverter issues above. Its just a case of whether the installer would be interested in doing it and of course whether its worth the cost.

I may ask for quotes for both and see what they come back with. It could be neither are worth it!
 
thewanted said:
Hi all. Looking for some advice and/or a sanity check.

I was pretty set on the following system:

16 x 435w panels
GivEnergy 13.5kwh All In One
Solis 6kw inverter

However, I've been running some calculations on our consumption and I'm worried that the AIO is too much for us. We used 4474kwh over a 346 day period (12.93kwh/day), which excludes EV charging. We've been on Intelligent Octopus Go since 05 November 2023, and over the last 11 days our peak time (05h30-23h30) usage has been 6.7kWh since we run the dishwasher and dehumidifier for drying clothes in the off peak period. This makes me think we could get away with a 9.5kWh battery instead.

Am I cutting it a bit fine? There's a £2750 saving going with a GivEnergy 5kw hybrid Gen 3 inverter + 1 x GivEnergy 9.5kWh Gen 2 battery over the system above.

I assume that I'll be reducing my potential export by going with the 5kw hybrid inverter over the Solis 6kw string inverter?
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Just signed the order form for:

16 x 435w Longi Hi-Mo6 panels
GivEnergy 5kW Hybrid Gen 3 inverter
1 x GivEnergy 9.5kWh Gen 2 battery

Can't wait to drive myself crazy with the data :)
 
Just bought another bargain of a battery to add. That’s 4 x US5000 now with a usable 18.24Kw. Also pushing over 5kw now on the discharge/charge. Just need to buy another 4 panels and I have maxed out pretty much everything. That would take me to around 10.8kw in panels.

Next year I will add another system if the dno are happy with the export potential. Though I really need to find a way to get octopus to take the DIY export or fork out for an MCS installer. Still waiting on their “trial non MCs”
 
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GivEnergy battery just started an upgrade to firmware 3015. Going to be a high-export day - hopefully it does it's thing before too long so it can get a bit of a charge in the batteries before it gets expensive! :D
 
Ron-ski said:
@BUDFORCE Just a guess here, but if using home assistant, could you put a relay in the CT clamp circuit, so if the battery is full, the relay reconnects the CT clamp, and then the iBoost uses the excess.

Think I've also heard of two CT clamps in series, one on the feed to the AC battery the other on the mains so it sort of cancels out, and thus the iBoost see's the true excess.
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I owe you a thank you, I took your idea, sort of.

I setup a relay that works from a car key type fob. Tested today as it's working, waited for battery to fill to 100% pressed the button on the keyfob and flips the iboost on.

It's not perfect as I cannot work it remotely, as in, still need to be within 20m or whatever, basically in the house. But I work from home anyway. It also relies on you keeping an eye on it, but feels better to have the option over permanently disconnected.
 
Freefaller said:
GivEnergy battery just started an upgrade to firmware 3015. Going to be a high-export day - hopefully it does it's thing before too long so it can get a bit of a charge in the batteries before it gets expensive! :D
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Wow you're brave lol!

Best time to kick off the firmware update is likely when battery is nearly empty and you're about to charge it anyway, as firmware update does a full discharge/charge cycle.
 
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