Solar power diverter / router (surplus-PV to resistive load)

Monitors PV export at the meter and diverts surplus (otherwise-exported) PV power to a resistive dump load, typically an immersion water heater, also underfloor heating or a pool pump, to maximise self-consumption without a battery. Well-documented open-source builds exist (Robin Emley's Mk2 PV Router; Andre Buhart's F1ATB 'routeur solaire'). Complements a PV array and direct-solar supply; an alternative to battery storage for time-shifting surplus into hot water.

Cost

Low-medium

Upkeep

None

Skill to build

Intermediate

Lifespan

10-15 years (power electronics); the resistive load (immersion element) follows its own longer cycle.

Embodied carbon

Low

Space / material use

Low

Output timing

Weather/time-dependent

Skill to repair

Intermediate

Regulation (FR example)

Fixed electrical installations must meet NF C 15-100, and a Consuel certificate is required before a new connection is energised. Grid-connected generation requires an Enedis connection agreement.

Note: Cost, carbon and footprint are rated against the other options for this same need, not in absolute terms.

What your site needs

Pairs with a PV array and a resistive load such as an immersion tank; works grid-tied or off-grid.

Inputs

• AC Electricity
• DC Electricity

Outputs

• Heated Water

Sources

• pv-magazine (open-source PV surplus routers) + OpenEnergyMonitor Mk2 PV Router documentation

Tutorials

• https://docs.openenergymonitor.org/pv-diversion/mk2/index.html
• https://www.youtube.com/watch?v=jieIqrAOqo8

What this page does not tell you

No sizing or quantities: how much a technique yields, and how much a household needs, both depend on the build and the people, so the catalogue compares options rather than dimensioning them. It carries no bill of materials and no build sequence, and it is written for an oceanic, clay-soil climate (Normandy, France). Regulatory notes are indicative and need confirming locally.