Solar panels and battery - any real world recommendations?

We are considering getting solar panels and a house battery fitted.

I've had a price from heatable of £19,150 for the following-

System details
–
Your custom design
Solar system size1
11.04 kWDC (STC)
Estimated annual production (MCS)
8,790 kWh
Battery size
13.5 kWh (13.5 kWh usable)
System efficiency2
95%
Solar panel
24 × 460W REA Power FUSION-R · REA-HDN96R-DSN-460
1,762 × 1,134 mm · Monocrystalline ·
Inverter
1 × Tesla Powerwall 3 · 11040W
Single phase · 97.5% max. efficiency ·
Battery storage3
1 × Tesla Powerwall 3 · 13.5kWh
609 × 1,099 × 193 mm · 13.5kWh usable · LFP · ·
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Our annual usage is circa 7,500Kwh. We have an EV but only do 8k miles year.

Our house is east to west facing. We have a detached garage facing north to south.

The plan would put 12 panels facing east on house, 9 facing west on house and 3 panels facing south on garage.

House is in South Wales and doesn't get any shade.

Is this a reasonable spec system and price? Early into our research and would appreciate some opinions.
Thanks.
 
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Heatable = very expensive (as that quote shows), get other quotes, try https://www.greenteamone.co.uk/

Fit as many panels as possible, battery size is probably about right, but if planning on getting a heat pump you may want a bigger battery, or at least a system that's easy to extend.
 
If you are putting 3 panels on the south side of the garage, put 3 on the north as well. They are about 50% of the generation of the south but still pack back as the marginal cost of adding them is usually tiny.
 
I do limit the charge current on the overnight charge, I have an algorithm that constantly calculates the charge rate to hit 100% SOC by 5am, the other half hour it just draws house loads from the grid, this gives the cells half an hour to balance every morning. I have a similar system for force discharge, so it hits my preset minimum SOC charge at the desired time - I have it discharging at the moment and it will hit 10% at 11:55 ready for the 3 hours of free electric.

I do this because its kinder on the grid, and kinder to my equipment, I have 6 hours off peak overnight, so might as well use all that time, rather than run at full tilt for just over half of it.

However during the free power hours (or three as todays is), it will charge at full power, often that's more than the inverter can supply, as its inverter plus solar, although with todays session I doubt the inverter will run at full power (8kW) as we have 13 kWh of solar forecast.
I do have preset limits, these are limits I've set, 18kW for the grid, 9kW going into the batteries for example.
 
Not sure why but my battery isn’t discharging currently even though I set it to Discharge but the solar generation is taking precedence.

Double checked my Mode Schedule and it's identical settings to the ones I use to Discharge late at night. The only difference is there's no PV generation late at night, but during the day there is. :confused:
 
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rangor gubbins said:
Does anyone reduce or limit the charge current that inverters charge their batteries with, to extend the life of the batteries (or perhaps the inverter)?
Our inverter is a 6kw inverter
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Yes although it’s mainly to keep the heat in check in the summer as discharging at 6kw and then recharging again at 6kw pegs the inverter at 70C for a few hours which isn’t ideal.

I’m more concerned about the control electronics and inverter than the batteries to be honest. Either way, once the warranty runs out, they’ll large be obsolete.
 
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Ron-ski said:
I do limit the charge current on the overnight charge, I have an algorithm that constantly calculates the charge rate to hit 100% SOC by 5am, the other half hour it just draws house loads from the grid, this gives the cells half an hour to balance every morning. I have a similar system for force discharge, so it hits my preset minimum SOC charge at the desired time - I have it discharging at the moment and it will hit 10% at 11:55 ready for the 3 hours of free electric.

I do this because its kinder on the grid, and kinder to my equipment, I have 6 hours off peak overnight, so might as well use all that time, rather than run at full tilt for just over half of it.

However during the free power hours (or three as todays is), it will charge at full power, often that's more than the inverter can supply, as its inverter plus solar, although with todays session I doubt the inverter will run at full power (8kW) as we have 13 kWh of solar forecast.
I do have preset limits, these are limits I've set, 18kW for the grid, 9kW going into the batteries for example.
Click to expand...
What system is controlling that and if it's home assistant, would you be willing to share your aautomation algorithm
 
Mines a Victron system, and I use Node Red directly on the Victron system, the code is very system specific, it would be a lot of work to adapt for another Victron system let alone a different inverter, so even though you can run Node Red on HA there would be a massive amount that needs changing, it would be better to start from scratch.

There is a HA addon called PredBat, many on here use it, might be worth a look https://springfall2008.github.io/batpred/what-does-predbat-do/
 
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I run home assistant in a docker on my synology nas. This HA doesn't come with 'add-ons'. I don't know much about using docker, but managed to get predbat running in docker. Haven't managed to get it to work or connect to home assistant though.
 
timmy85 said:
I've had a price from heatable of £19,150 for the following-
Click to expand...

Oof... £20k for that - FYI Heatable are a joke of a company in terms of any value, they don't have such a thing. They spend lots on marketing giving cheap/free systems to YouTube/Influencers to pretend they are the best when they are far from it they also rely on sub contracted installers.

Are they quoting 2x Powerwall's and main and an extension?
 
Dandle said:
My two PW3 never discharge the battery to the grid. I just set thm to be fully charged by 05:30 am then the solar tops them up in the morning. Once full all the solar goes to the grid.
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Normal service has resumed, it must have been the AI getting confused with my sudden peak of hot tub usuage, so it was saving everything to fill the battery
 
Journey said:
They spend lots on marketing giving cheap/free systems to YouTube/Influencers to pretend they are the best when they are far from it they also rely on sub contracted installers.
Click to expand...
basically the average joe is being suckered into subsidising their influencers' installs :cry:
 
Journey said:
Oof... £20k for that - FYI Heatable are a joke of a company in terms of any value, they don't have such a thing. They spend lots on marketing giving cheap/free systems to YouTube/Influencers to pretend they are the best when they are far from it they also rely on sub contracted installers.

Are they quoting 2x Powerwall's and main and an extension?
Click to expand...

Thanks for the feedback. I'm awaiting some quotes from some local companies too.

What is a fair price for a system of that nature then if19k is expensive?
 
I've seen a few Ecoworthy 'sponsored' videos of their panels and battery storage, to be fair they do look pretty good but not sure we get the new version over here yet.
 
I've got Solax and I limit my charge rate now that it easy to do with the TOU stuff they implemented.
I now charge at 2.5kw rather than the default of 5.5kw
Also helps in that some activity in the batteries generates some heat. When they were charging at 5.5kw they would sit there for three hours doing nothing which in the depths of winter means they got colder.
Now generally they sit there for an hour which isn't too bad.
 
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