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

Practical and DIY

Sunsynk timer SOC depends on Grid Charge: with it selected the row can be a charge level; without it, discharge towards that level may be allowed.
Find the binding constraint: source-specific current, timer Power, BMS requests, equipment limits, available energy and time can all restrict battery power.
Priority Load and Priority Battery change where solar goes: a timer SOC is not a universal cap on solar charging.
Diagnose in a fixed order: identify the active row and source permissions before changing current limits or protection values.
Keep protection and compliance settings out of experiments: grid code, CT wiring, battery protocol and firmware need the exact manual or an installer.

Updated 15 Jul 2026 Read Entry →

Practical and DIY

Sunsynk CT clamp accuracy drops beyond 15 metres of cable — signal attenuates over distance.
Budget workaround: extend the cable and calibrate the offset in Solar Assistant config.
Proper fix: install a dedicated energy meter (e.g., Eastron SDM230) closer to the consumer unit.
Why it matters: inaccurate CT readings cause the inverter to export when it should not, or import when it has stored energy.

Updated 15 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 15 Jul 2026 Read Entry →

Energy Utilisation

Outgoing Octopus is the product family: Fixed for simple solar, Agile for timed export, Flux when a battery can hit the peak window.
Rates move. Figures on this page are a July 2026 snapshot. Confirm live prices on Octopus before you design payback around them.
Agile tracks wholesale; Fixed is slower to reprice and can lag the market up or down after a change.
DIY without MCS? See export from a DIY system. Battery-only arbitrage lives on battery without solar.

Updated 14 Jul 2026 Read Entry →

Fundamentals

July 2026: there is no universal free solar grant for typical UK homeowners – self-fund with 0% VAT and SEG is the normal path.
Scheme map: VAT (near universal), SEG (export pay), ECO4 and Warm Homes (means-tested), group buy (discount only).
Free solar is rare: only where ECO4 / Warm Homes / Nest eligibility and delivery actually include PV.
Ignore lead-gen “free panels” ads that harvest details without naming a real qualifying scheme.

Updated 14 Jul 2026 Read Entry →

Practical and DIY

Check G98 headroom first: a 4-panel garage array usually fits under 3.68kW AC if it is the only inverter on site.
Hardwire, do not plug in: shed solar needs its own breaker via a registered electrician. Socket kits are not legal yet.
Prefer AC cable runs from a local inverter to the house consumer unit over long DC strings.
With a battery, ROI can fall under 3 years on a well-used base load.
A summer house used as an office pays back faster because daytime load matches generation.

Updated 14 Jul 2026 Read Entry →

Fundamentals

A 4kW system at about £7,000 pays back in 12-13 years for high self-use homes, then delivers roughly a decade of much lower effective unit cost after payback.
Skip solar if heavy shade, a north roof, under 6kWh/day use, or a move inside 5 years stretch payback past the point of sense.
Self-consumption decides the result: using your own solar saves about 27.69p/kWh; exporting it can earn as little as 5p.
A battery lifts self-consumption to 70-80% and usually beats panel-only setups on total returns.

Updated 14 Jul 2026 Read Entry →

Fundamentals

Yes, battery without solar works when you have a real TOU peak/off-peak spread and you cycle the pack most days.
Run the payback worksheet with your usable kWh, rates, and RTE before you buy.
Kill the project if the spread is thin or you will not cycle daily on a flat tariff.
Charge Pack is separate from home battery control; EV smart charge and battery charge windows must both be planned.
System cost ~£3,300 for a typical DIY-leaning 16kWh route (battery + inverter + electrician). 0% VAT until March 2027.

Updated 14 Jul 2026 Read Entry →

Fundamentals

Plug-in solar is still not legal in the UK, but the rules are moving: the consultation closed in June 2026 and Germany already runs 1.2 million plug-in systems.
Cloudy days do not switch panels off: they still produce 10-25% of rated output, and cloudier Germany got about 12% of its electricity from solar in 2023.
Modern panels lose about 0.4% of output a year: leading manufacturers now guarantee 87-90% of original capacity at year 25.
You no longer need £5,000 to start: a two-panel 1kWp starter kit costs £300-500 in hardware, hardwired by an electrician until socket kits are approved.

Updated 14 Jul 2026 Read Entry →