Solar Energy Concepts

DIY Solar for UK Homes. Real guides from a real install.

Step-by-step practical guides, component lessons, and hard-earned fixes from a real UK DIY solar setup.

7.15kWpinstalled 6,072kWhgenerated 2025 £1,668/yrmodelled value

Latest field notes

Energy Utilisation

A UPS bridges the switchover; a battery on the inverter’s LOAD port gives you 8-27 hours: for a local AI server you want both layers, not one or the other.
A 1500VA UPS holds a 400W inference rig for about 10 minutes, not 30: manufacturer runtime figures and lead-acid ageing make the small-UPS-only plan worse than most people assume.
No mainstream inverter datasheet guarantees a millisecond switchover: GivEnergy documents roughly 5 seconds in standard EPS mode, and Sunsynk publishes no transfer time at all. Your ATX PSU is only required to ride through 17ms.
16.1kWh of battery runs a 400W rig for about 27 hours, not the 40 the nameplate suggests: usable capacity, conversion losses and the inverter’s own draw take a third off.
The LOAD-port circuit is a designed electrical installation, not a plug-in accessory: island-mode earthing, DNO rules and BS 7671 Amendment 4 (in force 15 April 2026) put it in professional territory.
A 24/7 400W box consumes about 3,500kWh a year: a battery on a time-of-use tariff cuts its running cost sharply, but count forgone export and battery wear before calling the electricity free.

Updated 10 Jul 2026 Read Entry →

Practical and DIY

Automate battery charging using Solar Assistant, PV forecasts, and overnight tariff rates to maximise winter savings.
Simplest setup: charge from grid overnight on Octopus Go at 7.5p/kWh, discharge during peak hours.
Advanced: use Forecast.Solar API + Solar Assistant rules to decide whether to charge from grid or wait for solar.
Works with Sunsynk and Deye inverters via MQTT control through Solar Assistant.

Updated 10 Jul 2026 Read Entry →

Practical and DIY

Solar panels for a shed: hardwire them to their own breaker via a registered electrician. Plug-in kits are not legal in the UK yet.
Full DIY gives more power — 4 panels + string inverter on a garage roof can cover your home base load.
With a battery, ROI drops to under 3 years — store daytime generation for evening use.
Part P applies: wiring a detached building still requires building regulations notification.
Plug-in kits may become legal later: the government consulted in June 2026 and is analysing responses, with no confirmed date.

Updated 10 Jul 2026 Read Entry →

Practical and DIY

The Sunsynk 3.6kW can accept higher DC input than many owners realise, within limits.
Correct design and settings matter — otherwise potential yield is left on the table.
This guide explains practical configuration for better generation and export outcomes.

Updated 10 Jul 2026 Read Entry →

My Components

~10% capacity loss after 3 years and 600 cycles. Well within the 4,000-cycle warranty. At this rate, 80%+ capacity at the 10-year mark.
You can add a pack later, even at different cycle count. The BMS recalibrates. I did it, and the readings have since converged.
How I charge: Octopus Go + Solar Assistant automation. Saves £1,668/year. The setup details are in this article.
Honest drawbacks included. Winter balancing drift, BMS firmware update, and how the fix works.

Updated 10 Jul 2026 Read Entry →

Energy Utilisation

Installers size for annual average. Typical UK household sits at 7.4 kWh/day, pointing the formula at an 8 to 10 kWh battery.
Winter usage is +27% higher and solar drops to 29.6% of summer yield. Average sizing leaves a gap.
Extra capacity at install earns £59 to 72/year per kWh on a time-of-use tariff, with 4 to 6 year marginal payback.
Retrofit costs 30 to 50% more than the same kWh added at install.

Updated 10 Jul 2026 Read Entry →

Fundamentals

Most UK homes need a 5-10kWh LFP battery to store surplus solar generation and avoid selling it back to the grid at 4-15p/kWh only to buy it back at 24-35p.
LFP (lithium iron phosphate) is the standard choice in 2026: 6,000+ cycles, no thermal-runaway risk, and around £124-176/kWh at the right sizes.
Size your battery to cover your full daily consumption, not just evenings. A 3-bed home using 2,900 kWh/year needs roughly 5.3kWh usable capacity plus 20% headroom.
DC-coupled batteries with a hybrid inverter are cheaper for new systems; AC-coupled makes sense when retrofitting storage to an existing solar setup.

Updated 10 Jul 2026 Read Entry →

Fundamentals

Panels make DC, a microinverter converts it to 230V AC: your home uses that power first, then draws the rest from the grid automatically.
Two panels produce up to 800W, enough to cover a typical home’s 200-400W daytime base load with some left to spare on a sunny day.
The government’s 2026 safety study tested six plug-in kits: all passed for safe operation, but all exceeded a radio-interference (EMC) limit at full power, and the study recommended enabling plug-in solar, not banning it.
You cannot legally plug one into a UK socket yet: the government consulted on the rule change in June 2026 and is analysing responses, with no confirmed date for a decision.

Updated 10 Jul 2026 Read Entry →

Fundamentals

A 4kW system at £7,000 pays back in 12-13 years at January 2026 prices, then delivers roughly a decade of near-free electricity.
Self-consumption decides the result: using your own solar saves 27.69p/kWh, exporting it earns as little as 5p.
A battery lifts self-consumption to 70-80% and usually beats panel-only setups on total returns.

Updated 9 Jul 2026 Read Entry →