My Solarteur

Three quotes for a photovoltaic system. Each time, prices that make a Swabian feel sick. The roof hooks are already mounted, the conduits are laid, the preparation is done. You literally just need to slap the panels on. And yet: five-figure quotes. For work that — if I'm honest — I can do myself.

When the smart home dream gets too expensive

I'm one of those people. Alexa in every ceiling, automation everywhere, the whole house networked. My dream was always a fully smart home — KNX, central control, everything integrated. Then came the quotes: nearly 100,000 euros. For cables, actuators, and programming. That was the moment I decided to do it myself.

I planned and executed the entire electrical installation of my house. From the main distribution board to the last outlet, all done by myself. Only the final inspection was done by a friend who's an electrician. As a mechanical engineer and mechatronics specialist, I have a different relationship with the subject than most homeowners — I can read circuit diagrams, calculate torques, and I know what happens when you send 600 amps through an undersized contact. Once you've seen the margin between material costs and a contractor's invoice, you look at quotes differently.

After building the house, I actually wanted to spend more time with the kids. So I thought: let someone else handle the solar system. Then the quotes came in. Three solar installers, three philosophies, three price tags — and none of them made sense if you know material costs. Déjà vu.

More than just solar panels

I never just wanted panels on the roof. I wanted an Energy Storage System. Autarky. A large battery bank networked with Home Assistant. Energy trading via Tibber — a system that buys cheap and consumes expensive. And for that, there was no off-the-shelf offer.

When I told my friends, most just shook their heads. Massive storage? Self-built? Energy trading? You don't do that yourself. Yes, you do. When you've already electrified an entire house, a PV system is the logical next step.

How an agent becomes a solar consultant

But — and this is the point — I couldn't have done it alone. Not because I can't, but because the complexity explodes. DIN VDE 0100, Victron-specific configuration, MPPT string calculations, NH3 fuse dimensioning, the M10 paradox on Lynx modules, torque specifications for different bolt sizes. Every decision has consequences, and at 48 volts and 600 amps, wrong decisions aren't just expensive — they're dangerous.

So I built myself a specialized AI agent. Not a generic chatbot. A solar consultant who knows my project — 26 markdown files as a knowledge base. System architecture, component lists, decision protocols, safety rules. Every question is answered against this knowledge base, not from gut feeling.

The result: I could ask questions at midnight that I can't ask any electrician at midnight. Which cable lug for which bolt? Why M8 instead of M10? What happens on the negative path when the KETO disconnect switch is open? And the agent didn't guess — it looked up my own documentation and answered.

What came out of it

A two-phase project. Phase 1: The ESS core system — batteries, inverters, emergency bypass. Phase 2: PV modules across four surfaces — roof, solar fence, terrace, garden shed. Everything planned through, from mechanical mounting to DC wiring to commissioning. Every part number verified — and trust me, with Victron, a wrong part number can mean the difference between a working system and a fire hazard.

The lessons learned alone fill their own document. The Lynx M10 paradox: The “M10 version” has M10 busbars on the sides, but all cable bolts are M8. If you put M10 lugs on M8 bolts, you get insufficient contact area at 600 amps. That's in no brochure.

AI as co-planner, not replacement

My AI solar consultant didn't plan the system for me. It enabled me to plan it myself — with the detailed knowledge that normally requires ten years of professional experience. It saved me from expensive mistakes, checked my decisions against standards, and helped me turn 26 individual documents into a consistent system. And since I know how much AI agents love to hallucinate and make things up, everything was validated and verified two and three times over. Every specification against the original data sheet, every part number against the manufacturer.

And that's exactly the core: AI doesn't replace an electrician. But it turns an ambitious homeowner into an informed conversation partner. The AC side is still done by the professional. But when I talk to him, we speak as equals — because I know my system better than any solar installer who writes three quotes a day.

Of course, I'll have the entire plan verified by a solar expert in the end. The system is complex, and a second opinion from a professional isn't weakness — it's part of the process. But the difference: I don't come as a layperson asking “What should I get?” I come with a fully planned system and say “Please check this.”

And that's exactly what I want to make available to others. The idea: making the solar consultant agent available as its own app. Not as a replacement for the installer, but as a tool that supports homeowners and professionals alike. So the next solar project doesn't start with three incomprehensible quotes — but with knowledge.

— Philipp