Off-Grid Solar System Design
Constraint-Driven Planning for a California Homestead
Project: Residential off-grid solar system design Client: Homeowner, Central California Status: Complete — ready for construction Deliverable: 6 technical reports (337 pages) + 3-page client summary Role: Design, analysis, and planning — not installation
The Problem
A California homeowner needed to move off-grid. The daily load was 16 kWh. The budget was uncertain. The constraints were not:
- NEC 2020 and California Title 24 compliance required
- Seismic design considerations for ground mount
- Some work could be DIY; some legally required a licensed electrician
- Existing solar panels on-site (potential reuse)
- Battery lead times of 4-12 weeks
The client needed to make a decision. They needed to understand what they were deciding.
The Approach
Instead of delivering a single recommendation, the project produced three distinct budget tiers with transparent tradeoffs:
| Tier | Cost | 20-Year TCO | Risk Profile |
|---|---|---|---|
| Budget | $21,000 | $38,500 | Higher maintenance, shorter warranty |
| Mid-Range | $27,500 | $32,500 | Lowest lifecycle cost, balanced risk |
| Premium | $40,000 | $45,000 | Maximum redundancy, longest warranty |
Each tier included:
- Complete bill of materials
- Installation timeline (Gantt chart)
- Code compliance matrix (NEC 690, 706, 710, 705, 250)
- 20-year maintenance projections
The Boundary
The project explicitly separated what the homeowner could safely do themselves from what required a licensed electrician:
Homeowner scope (legal, safe):
- Ground mount assembly
- Conduit runs
- Equipment labeling
- System monitoring setup
Licensed electrician required:
- AC/DC connections
- Main panel work
- Utility interconnection
- Final inspection sign-off
This distinction protected the client from liability while preserving their agency over the parts they could control.
The Outcome
Delivered:
- 6 technical reports (337 pages)
- 230+ item safety compliance checklist
- 3-page non-technical client summary
- Supply chain alert (EG4 batteries: 4-12 week lead time)
Identified savings:
- $4,560 by reusing existing on-site solar panels
- $81,000 advantage of LiFePO4 over AGM batteries (20-year comparison)
Design choice:
- Ground mount selected over roof mount
- Rationale: no structural modifications, easier maintenance, better thermal performance, 25+ year lifespan vs 10-year ballasted alternative
Values in Practice
Clarity Over Complexity Three budget tiers with transparent breakdown. Non-technical summary for decision-makers. Deep technical specs for engineers and inspectors. The client could understand what they were choosing without needing to understand everything.
Consent Is Structural Four execution paths provided (Budget/Mid-Range/Premium + DIY vs Professional split). The client chose their own risk tolerance. The system didn’t choose for them.
Endurance Over Speed Ground mount with 25-year fixed structure chosen over faster-to-install 10-year ballasted system. Higher initial cost, lower lifetime cost, fewer failure points.
Local-First Design System designed to function when grid is absent, utility support is unavailable, and institutional infrastructure cannot be relied upon. That was the entire point.
What This Demonstrates
Complex decisions don’t require complex communication. A 337-page technical archive and a 3-page client summary can coexist. The depth exists for those who need it. The clarity exists for those who need to decide.
Constraint was the input. Legibility was the output.