Mike Swanson
aaf4172b3c
New projects from 2026-02-09 research session: Wrightstown Solar: - DIY 48V LiFePO4 battery storage (EVE C40 cells) - Victron MultiPlus II whole-house UPS design - BMS comparison (Victron CAN bus compatible) - EV salvage analysis (new cells won) - Full parts list and budget Wrightstown Smart Home: - Home Assistant Yellow setup (local voice, no cloud) - Local LLM server build guide (Ollama + RTX 4090) - Hybrid LLM bridge (LiteLLM + Claude API + Grok API) - Network security (VLAN architecture, PII sanitization) Machine: ACG-M-L5090 Timestamp: 2026-02-09 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
119 lines
3.7 KiB
Markdown
119 lines
3.7 KiB
Markdown
# Wrightstown Solar - Project Index
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**Project:** DIY Home Solar Battery Storage
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**Location:** Wrightstown (home)
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**Status:** Planning / Research Phase
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**Created:** 2026-02-09
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**Last Updated:** 2026-02-09
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---
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## Project Overview
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DIY 48V LiFePO4 battery storage system for whole-house UPS / backup power with generator failover. Designed for modular expansion from 5kWh to 20kWh.
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## Target System Specs
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| Spec | Value |
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| Chemistry | LiFePO4 (LFP) |
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| Cell | EVE C40 (40135 cylindrical, 3.2V 20Ah) |
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| Configuration | 16S5P per 5kWh pack |
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| Nominal Voltage | 51.2V (48V system) |
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| Pack Capacity | 5.12kWh per pack |
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| Target Total | 20kWh (4 packs) |
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| Inverter | Victron MultiPlus II 48/5000 |
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| BMS | JK BMS B2A8S20P 150A (recommended) |
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| GX Device | Cerbo GX |
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| Existing Solar | Fronius IG Plus (grid-tie string inverter) |
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## Design Goals
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1. Seamless switchover when grid drops (<20ms, UPS-grade)
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2. Zero grid backfeed (physical relay disconnect)
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3. Generator input for extended outages
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4. Modular expansion (build one 5kWh pack at a time)
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5. Fronius solar continues working during outages via Victron micro-grid
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## Architecture
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```
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NORMAL OPERATION
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Grid -----> [Victron MultiPlus II] -----> House Panel
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[48V Battery]
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(EVE C40 packs)
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Generator ---> [AC Input 2]
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GRID DOWN
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Grid --X [Victron MultiPlus II] -----> House Panel
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(relay OPENS, no backfeed)
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[48V Battery] (discharging)
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Generator ---> [AC Input] (if battery low)
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```
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---
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## Files
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### Documentation
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| File | Description |
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| `documentation/system-design.md` | Full system architecture and component specs |
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| `documentation/bms-comparison.md` | BMS models compatible with Victron CAN bus |
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| `documentation/ev-salvage-analysis.md` | Analysis of salvaged EV packs vs new cells |
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| `documentation/parts-list.md` | Bill of materials and estimated costs |
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### Session Logs
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| File | Description |
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| `session-logs/2026-02-09-session.md` | Initial research and planning session |
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---
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## Budget Estimate
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### Phase 1 (5kWh + Victron System)
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| Component | Est. Cost |
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| Victron MultiPlus II 48/5000 | $1,400-1,800 |
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| Cerbo GX | $320-350 |
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| JK BMS B2A8S20P 150A | $80-150 |
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| 80x EVE C40 cells | $240-400 |
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| USB-UART cable | $15 |
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| Cell holders, bus bars, wiring | $60-120 |
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| Fuses, breaker, enclosure | $60-110 |
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| **Phase 1 Total** | **$2,175-2,945** |
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### Phases 2-4 (Additional 15kWh)
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| Component | Est. Cost |
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| 3x additional 5kWh packs (cells + BMS + hardware) | $1,140-2,010 |
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| **Full 20kWh System Total** | **$3,315-4,955** |
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---
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## Decision Log
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| Date | Decision | Rationale |
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| 2026-02-09 | EVE C40 cells over salvaged EV packs | Lower $/kWh ($190-282 vs $365-780), longer life, LFP safety, simpler build |
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| 2026-02-09 | 5kWh modular packs (not 10kWh) | Spread cost, manageable builds, fault isolation, one-person liftable |
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| 2026-02-09 | Victron MultiPlus II for inverter | <20ms UPS switchover, physical relay anti-backfeed, generator support, micro-grid for Fronius |
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| 2026-02-09 | JK BMS B2A8S20P (recommended) | 2A active balancing critical for cylindrical cells, best value, huge community |
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| 2026-02-09 | Keep Fronius IG Plus | Still functional; AC-couple via Victron micro-grid during outages |
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---
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## Next Steps
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- [ ] Finalize BMS selection (JK BMS vs REC BMS vs SEPLOS)
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- [ ] Source EVE C40 cells (Grade A, matched, with test data)
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- [ ] Order Victron MultiPlus II 48/5000 + Cerbo GX
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- [ ] Design cell holder / bus bar layout for 16S5P cylindrical pack
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- [ ] Plan sub-panel / transfer switch wiring
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- [ ] Build Pack 1, test for 1 month before expanding
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