Solar panels and battery - any real world reccomendations?

[John J Sheridan]

So I'm thinking about getting solar panels fitted. From what I've read here, people are saying Octopus is the best company to be with for electric if you have solar panels. Would people agree with that?

If we did go with them - do they install solar panels or should I just find a local company?

Also thinking about getting home battery storage.

 

[tamzzy]

So I'm thinking about getting solar panels fitted. From what I've read here, people are saying Octopus is the best company to be with for electric if you have solar panels. Would people agree with that?

If we did go with them - do they install solar panels or should I just find a local company?

Also thinking about getting home battery storage.

if you're willing to alter your leccy use based on rates then octopus is a no brainer
for everyone else (including myself) who wants a "set-and-forget" system then e.on is the next best thing

eon next drive fixed 1 year: 7p/kwh from 0000-0659
solar export: 16.5p/kwh

in my case, i charge my batteries fully overnight and then sell all the excess solar during the daytime
i've "saved" about £380 this way and exported £426 in the last year, so approx £800/year (my PV system cost £8.3K)

 

[Martynt74]

Unsure if this really belongs in here, but is there any plug in power meters which can measure/store the whole house demand to provide reporting? Kind of like the smart meters that energy companies send out, but completely separate from the provider?

We're in a rental (in Spain) and whilst the landlord provides the invoice which shows usage by day, i'm unable to see real time data. We're building our house and i want to make sure our solar system is sufficient as we're 100% off grid. There's only 2 of us and i can make a rough list of the devices with a guess of usage, but it's hard to see peak loads or spikes to know whether my currently specced system has the capacity.

 

[Mercenary Keyboard Warrior]

Unsure if this really belongs in here, but is there any plug in power meters which can measure/store the whole house demand to provide reporting? Kind of like the smart meters that energy companies send out, but completely separate from the provider?

We're in a rental (in Spain) and whilst the landlord provides the invoice which shows usage by day, i'm unable to see real time data. We're building our house and i want to make sure our solar system is sufficient as we're 100% off grid. There's only 2 of us and i can make a rough list of the devices with a guess of usage, but it's hard to see peak loads or spikes to know whether my currently specced system has the capacity.

Your getting battery as well right?
So you need to know what the inverter is able to supply from both sources they are not necessarily the same, but may be.
Eg a 5kw inverter will likely supply 5-6 depending on the make. Usually at the bottom end of that range but some are more limited with the batteries.
Bigger inverters aren't much more money so I would certainly take the cautious approach and go big.
Bigger inverters are slightly less efficient in low light situations as inverters are more efficient at rated capacity than below it.

In regards usage. I have never seen what you describe but they do exist in some form as a company I worked for had them on all devices in the factory.
It was a good monitor for potential issues apparently as impending failures usually stressed something and that meant the equipment used more power.

I can give you an idea that in a decent size house with a baseload of 500w or so I never really go above 5.5kw (my inverter max).
If I put the DW on, then immediately switch on the washing machine and the kettle I can go over that.
You only really need to worry about the big units. What probably worth doing is monitoring each alone anyway with a plug in socket.
Eg DW will spike to heat the water, but most of the cycle (bar iirc 3 heating sessions) its only like 400w. Washing is actually similar.
What you cant do ofc with no grid backup is line up the spikes when both those devices are heating.

Many things with high potential draw only do it irregularly. So mainly when heating water (DW/washing/kettle), AC can have a short spike when getting going.

 

[john_smith]

Assuming you can get enough sun I would think 40kw of storage might be safe enough for 2 people. But will you have AC on all day and night? What happenes when there's no sun for 2 or 3 days in a row? Candles?

 

[Martynt74]

Good call on the big items. I also need to look into swimming pool pumps, although i assume they're not too high current but just expensive due to the length of run time which shouldn't be too big an issue.

Yeah, think we've got 20kwh of battery storage so not too concerned there, especially given Spain is generally bright enough even in bad conditions. The Inverter currently specced is the Multiplus 2 8000VA, but i'm planning on upping that to the Quattro 10000va i think so it can auto switch to a generator.
Main concerns at the moment are that we initial quote was from ~April 2024 when we signed the contract as the solar is included in the house build. Any changes now might be a little awkward, but i have the full breakdown so hopefully can just get the difference between the current prices

 

[Martynt74]

Assuming you can get enough sun I would think 40kw of storage might be safe enough for 2 people. But will you have AC on all day and night? What happenes when there's no sun for 2 or 3 days in a row? Candles?

We've got 20kwh of battery and was hoping that would be sufficient. We're on a central split air system powered by a heatpump so yeah that i need to factor in as it's likely to be running pretty constantly, although the house is being built as well insulated as possible to minimise excess heating demands.

 

[Mercenary Keyboard Warrior]

What your going to want to do is put some things onto an overnight schedule. Pool pumps may well be one that makes sense to do. DW is a classic almost all of us on a TOU tariff do, but its the same impact for you and limiting peaks.

10KW I would say your almost certainly not going to go above that unless you try.

Backup gen, assuming you mean a diesel/petrol? I think that can also be used to support load but there are a lot of ways to do this stuff so certainly don't take that as granted.
Also some batteries and inverters will allow short overload peaks. You really want to understand fully what it can and cannot do.

What make batteries are you getting, I would certainly make sure personally they are expandable above what your getting.
The tech does keep moving, my house batts for example were the max I could have, but since then the manufacturer has developed a box that allows double what I have.

Are you going to on demand water heat, or hot tank? Hot tank is a good heatsink for you for excess solar generation. Plus a well insulated hot tank you can stop heating if you know your going to have a couple of days of iffy generation.

 

[Martynt74]

Backup gen, assuming you mean a diesel/petrol? I think that can also be used to support load but there are a lot of ways to do this stuff so certainly don't take that as granted.
Also some batteries and inverters will allow short overload peaks. You really want to understand fully what it can and cannot do.

Yeah, i was working on a backup diesel gen just for contingency. At least to keep running heat/water if nothing else in the event of any issues. The Victron Multiplus can provide double for 60 seconds from an overload capacity from what i've seen. I assume the Quattro also can.

Batteries were these Pylon Tech 2.4kwh, but the quote is from Nov 23 and so i imagine technology has moved on since then so unsure if there's anything better now. I know there are definitely some 3.6kwh options available now which might offer better value/expansion.


Also need to decide where to store all this stuff. The initial plan was to house everything in the Utility room of the house, but i'm wondering if the garage makes more sense. Last thing i need is to want to expand and add another storage rack and not have space because we're limited in the utility room due to other storage needs. My plan was also to have all networking equipment in the utility, as i wasn't confident of the load capacity of a single cable run to a switch in the house to run through whole home network.

Pretty sure water is through a hot tank, but it's on my list to verify because we have a mix of filtered but not drinking water for showering and washing etc (but fine for brushing teeth) and then a water deposit with drinking water for supplies to the kitchen, but i'd then need to ensure both feeds could be heated.
Maybe i need to re-think and just have the drinking water supplied to the fridge/drinking water tap and then run everything else from the filtered non drinking water.

 

[Mercenary Keyboard Warrior]

Yeah, i was working on a backup diesel gen just for contingency. At least to keep running heat/water if nothing else in the event of any issues. The Victron Multiplus can provide double for 60 seconds from an overload capacity from what i've seen. I assume the Quattro also can.

Batteries were these Pylon Tech 2.4kwh, but the quote is from Nov 23 and so i imagine technology has moved on since then so unsure if there's anything better now. I know there are definitely some 3.6kwh options available now which might offer better value/expansion.


Also need to decide where to store all this stuff. The initial plan was to house everything in the Utility room of the house, but i'm wondering if the garage makes more sense. Last thing i need is to want to expand and add another storage rack and not have space because we're limited in the utility room due to other storage needs. My plan was also to have all networking equipment in the utility, as i wasn't confident of the load capacity of a single cable run to a switch in the house to run through whole home network

It moves on slightly or in jumps. And each manufacturer is different.
Some small are fine, others work out expensive, it just depends on the manufacturer in what kit you need for connecting multiples and things like expansion boxes etc.
Lots of small ofc has the advantage if one fails then the impact is less
@ronski may have better ideas on what works for your planned inverter, I know we would be recommending Fogstar in the UK for those sorts of capacity but your in spain so not sure that makes sense.

Bear in mind garage can cause temp issues. (Codl not hot I would say, batteries prefer heat)
It generally only impacts their charge rate when close to zero C. Which is unlikely to be an issue in a garage in spain right?
When charging/discharging they generate some heat themselves. Just a warning but I dont think even in the coldest points it should be a issue for you.

 

[Martynt74]

Bear in mind garage can cause temp issues. (Codl not hot I would say, batteries prefer heat)
It generally only impacts their charge rate when close to zero C. Which is unlikely to be an issue in a garage in spain right?
When charging/discharging they generate some heat themselves. Just a warning but I dont think even in the coldest points it should be a issue for you.

Worth adding that when i say "garage" it's what my wife has nicknamed my "office/house/garage". Effectively a 60m2 building where i'll have an office, gym and workshop storage. It'll be fully insulated and with some heating (maybe pellet burner) so unlikely to ever be too cold for the batteries.

Am in the process of scheduling a catch up with the builder as there's a few things we want to get sorted and agreed on. This can be one of the things. Hopefully i can also get details on the heatpump being used for climate control so i know what kind of loads that's likely to need.

 

[Mercenary Keyboard Warrior]

Worth adding that when i say "garage" it's what my wife has nicknamed my "office/house/garage". Effectively a 60m2 building where i'll have an office, gym and workshop storage. It'll be fully insulated and with some heating (maybe pellet burner) so unlikely to ever be too cold for the batteries.

Am in the process of scheduling a catch up with the builder as there's a few things we want to get sorted and agreed on. This can be one of the things. Hopefully i can also get details on the heatpump being used for climate control so i know what kind of loads that's likely to need.

In that case I would 100% personally put solar system in there.
Whilst fire etc are pretty rare they are not unheard of so having them away from the house and where expansion if needed could be easier makes total sense.

 

[Martynt74]

In that case I would 100% personally put solar system in there.
Whilst fire etc are pretty rare they are not unheard of so having them away from the house and where expansion if needed could be easier makes total sense.

Good call and something i'd not considered. Think i'll likely keep my network stuff in the house. With a small rack mount storage case it should fit relatively well and avoids too many issues with running cables for cctv i think.

 

[john_smith]

Where in Spain are you? I've an ex work colleage who I still follow on Facebook. He lives in this area:

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

www.google.com

And has solar and storage. Want me to ask him why his setup is, annual generation etc? If you're close it might give you an idea of what you can expect.

 

[Ron-ski]

@Martynt74 I'm short on time, so I'll keep this brief.

To answer your original question get a Shelly Energy Meter with a CT clamp.

Go for the Quattro 48/15000, that will give you 12kW of power, less if it's too hot.
Forget Pylontech, get 15 kWh batteries from Fogstar or direct from China, see Andy's off grid garage on YouTube.
If going off grid I'm pretty certain you'd want more than 20kWh of storage.

I've got a friend who's just buying a property inland from Almeria, 15kWp of panels would give them1800 to 2100 kWh a month, even in winter.

I run a Quattro 48/10000 with 29kWh of storage, all though it's in the UK

 

[Martynt74]

Where in Spain are you? I've an ex work colleage who I still follow on Facebook. He lives in this area:

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

www.google.com

And has solar and storage. Want me to ask him why his setup is, annual generation etc? If you're close it might give you an idea of what you can expect.

Yeah, that'd be great. He's around an hour away so close enough for a decent comparison (i'm in a place called La Romana to the north/west). I have also spoken to someone else who lives locally, although sadly he's considerably richer than me so it's hard to know if he's just overspecced everything to a huge degree or it's required.

The main issue is i'll be 100% reliant on solar so requirements are slightly different to people who have the grid to fall back on.

@Martynt74 I'm short on time, so I'll keep this brief.

To answer your original question get a Shelly Energy Meter with a CT clamp.

Go for the Quattro 48/15000, that will give you 12kW of power, less if it's too hot.
Forget Pylontech, get 15 kWh batteries from Fogstar or direct from China, see Andy's off grid garage on YouTube.
If going off grid I'm pretty certain you'd want more than 20kWh.

I've got a friend who's just buying a property inland from Almeria, 15kWp of panels would give then 1800 to 2100 kEh a month, even in winter.

I run a Quattro 48/10000 with 29kWh of storage, al though it's in the UK

Cheers. Pylontech is who the supplier was using. He's tied to the builder and there is a slight benefit going through the builder due to VAT benefits. Will see what other options are available though. Will look into that clamp, although it's use will be short lived so will likely depend on cost!
Unless this works?

Tuya Smart WiFi Energy Meter Bidirectional 2 Way with Clamp 80A, 120A, App Monitor Solar Produced and Consumed Power AC110V 240V - AliExpress 44

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