I’m trying to get an idea for how much is reasonable for an battery+inverter system including fitting. Would anyone like to share their system’s capacity, total cost, and when it was installed (as prices seem to move quite rapidly)?
How long is a piece of string…. It is one of those questions that is entirely dependent on your need. Do you need “Island Mode”, to just power a few devices if the power goes out, enough energy to get you through peak hours. You will probably be hampered, sorry restricted by the need of your DNO to balance your local grid so may only be able to have X amount of kWh capacitity. If you are off grid then you can pretty much have all the kWhs!
I am just waiting on a quote for some more panels and either a Sigenergy or (feels a little sick in my mouth) Tesla PW3 and extension pack. Take a look on heatables website they do a ton of different options and you will get a better idea of cost. They are deffo not the cheapest but they are a reputable company so a good place to start.
You could try here. Stick your post code in and you will get a ballpark estimate.
We had ours from another supplier a few years back and just finding an available installer was the hardest part and prices were pretty high at the time.
17x400W panels
6kW Solax Hybrid Inverter
11.6kWh Battery
EPS double socket (not full house backup)
For £13k
Very happy with the end result as the Solax integrates lovely into Home Assistant which was a key requirement for me.
As with all these renewable options, there are economies of scale.
Also ROI is based on your usage profile.
If you are tight, walk around in the dark, unplug stuff all the time and use minimal power, then £10K spent on a solar and battery install will take a long time to repay itself, if ever.
However if you work from home, have kids with games machines and/or pcs and don’t understand that a light switch has any position other than ON, you are likely to see high rewards!
If you are in the latter bracket, get as much solar as you can manage as you will not normally get another opportunity to add more panels when you understand you did not buy enough!
My 7kw solar install plus inverter cost around £9K three years ago and i spent about 5k on batteries since.
The heat pump looks like it will cost £490 from octopus!
I’ve since added more solar to another wall and fence and wish id done that in the first instance as it would have cost a fraction
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I don’t think the DNO cares at all about the capacity of your battery (i.e. energy). It does care very much about the maximum power you might contribute to the grid. You are required to get G99 approval if you might send more than 3.68 kW.
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28x 400W panels
2x 5kW hybrid Inverters (Luxpower)
9.4kWh battery (Hanchu)
EPS whole house
(26amp max but I think I would hit the battery max discharge rate before that, unless I add another battery)
16.5k Oct 23
https://craigmichael-renewables.co.uk/
I got a G99 allowing 10kW export
I can’t see the high export payments lasting long for times of day/year with lots of PV outout. Even this comming summer it is likely the grid will need to pay solar farms not to export.
Hence aim to maximise generation outside of times of peak generation. Eg East/West rather than south and if possible choose panel angles for winter output.
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Hey Dan – just to share my experience…
I went for the GivEnergy All-in-One 13.5kWh with the gateway – future-proofed for solar and gives me backup power during any outages. Cost was around £7k all in.
We’re running an all-electric house with a heat pump, no PV (yet), and it’s just the two of us DINKS (one working from home). Over winter, we were running the place 98% on Cosy off-peak, and now we’re pretty much 100% off-peak.
It’s knocked £80-90 a month off our electricity bill, so at current rates we’re looking at around a 6-7year payback. Will know more on savings as usage drops in the summer Honestly, really pleased with it so far!
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Of course you could always try to reduce your use first which will always be cheaper than maximising pv! 
Bristol, 3 bed mid terraced house
Install June 2024
2.1 occupants
£7,400 for 2 kwp array (5 panels), 3.7 kw fox hybrid inverter, fox ecs stackable batteries totalling 9.3 kWh. No island mode.
Total estimated generation 1800 kWh/annum. Based on 10.5 months use I reckon that’s about bang on.
No EV charger, on octopus agile tariff and fixed export 15 p/kwh.
Also have had a heat pump for about 18 months. I have worked out that the heat pump saves me £350-400/yr from reduced energy consumption and no gas standing charge and PV+battery+time of use tariff saves £450-500 from lower unit rate and export. Of course it’s not that straightforward because you end up doing stuff with a battery and/or time of use tariff that you wouldn’t have done without them.
My average unit rate since June last year, including elec standing charge and vat, was 22p/kwh. Once self usage is taken into account that reduces to 15p/kwh. Before June when just on a standard tariff, the all in elec unit cost was about 38p/kwh.
For me it’s not about the return on investment, it’s about making the house fit for use in the 21st century.
If there’s one thing I’d change it’s going for a bigger inverter. It would just mean I can use more power at any instant without using grid. Eg kettle + 1 hob ring is probs max a 3.7 kw inverter could do, but a 5 kw you could also chuck a toaster in the mix.
Any more for any more? I’m particularly interested in the cost of battery installs on their own (without solar); I just cannot get an idea of what’s a good price and what’s a bad price. But this is academic interest only.
I installed a 15kW sytsem with 5.5kW hybrid inverter nearly a year ago - all Sunsynk kit from ITS technologies. The invoice was for just under £5k, including cables etc.
We’re on Octopus Go Intelligent, 6.5kWp of solar and a Cool Energy ASHP. House is almost passive house standard in terms of heat loss - UFH in an insulated slab. No gas.
We turned the ASHP off about 6 weeks ago. Last month Octopus paid us ~£45. This month should be better. Before we installed the batteries, I’d worked out that it would be about a 5 year ROI but looking at things now, it will probably be earlier than that.
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Not really possible with an on roof install - we have a ground mounted array, so we set the angle to boost winter output and miss out on the max summer output - the panels are at about 45 deg.