⚡ LiFePO₄ Battery Bank Study
Architectural Immunity & Long-Term Storage Analysis
Overview
A DIY 12V 500Ah LiFePO₄ battery bank validated at 99% capacity with 130+ days of continuous voltage monitoring (Oct 29, 2025 – Mar 6, 2026).
This project demonstrates architectural immunity—the principle that parallel-connected mixed-brand cells achieve monolithic behavior through topology rather than cell matching.
Key Findings
| Metric | Value | Notes |
|---|---|---|
| 🔋 Usable Capacity | 397 Ah (99.3%) | Discharge test validated |
| 📉 Stasis Drift | −0.575 mV/day | Full 92-day stasis period |
| 🔋 Self-Discharge | ~0% | All loss from parasitic loads |
| ⚡ Parasitic Draw | 12.5 mA | Drok ~10mA + Shelly ~2-6mA |
| 📊 MA-60s Noise Reduction | 42–50% | Segment-dependent |
| 🌡️ Temperature Coefficient | +1.0 mV/°F | System-level |
| ⏱️ Storage Endurance | 11+ months | To 80% SOC at 12.5 mA |
Study Progress
| Phase | Status | Duration |
|---|---|---|
| Discharge Testing | ✅ Complete | Oct 2025 |
| Long-term Monitoring | ✅ Complete | 130+ days (Nov 2025 – Mar 2026) |
| Temperature Analysis | ✅ Complete | 62 days |
| MA-60s Validation | ✅ Complete | 712k samples |
| Charge Event Analysis | ✅ Complete | Feb 22, 2026 |
| Self-Discharge Analysis | ✅ Complete | ~0% confirmed |
| Direct Current Measurement | 🔲 Planned | Next step |
Quick Links
| Resource | Description |
|---|---|
| 📄 Full Technical Report | Complete analysis with all results |
| 🔬 Methodology | Statistical methods and definitions |
| 🔁 Replication Guide | Hardware setup and calibration |
| 🗺️ Evidence Map | Claim → data → code traceability |
| 📖 Glossary | Terms and abbreviations |
| ❓ FAQ | Frequently asked questions |
| 📊 Data | Raw datasets |
Expected Results for Replication
If you replicate this study, you should observe:
| Metric | Expected Range | Notes |
|---|---|---|
| Capacity | >95% of rated | Via controlled discharge test |
| Drift rate | −0.5 to −1.0 mV/day | Early stasis; flattens over time |
| Hourly spread | <50 mV typical | Bus-level max−min measurement (not cell-to-cell) |
| MA-60s reduction | 40–55% | Depends on sampling regularity |
Important: “Spread” in this study refers to the difference between hourly maximum and minimum voltage readings from a single bus-level sensor—it is not a measure of voltage difference between individual cells. Per-cell sensing would be required to measure cell-to-cell variation.
Core Claims
1. Architectural Immunity
No evidence of divergence at the common bus potential over 130+ days. Spread inflation post-Eco Mode correlates with measurement-regime change, not electrochemical imbalance.
2. Storage Viability
Drift is approaching equilibrium (21% rate reduction in final 30 days). Projected 11+ months to 80% SOC at measured parasitic draw of 12.5 mA. Self-discharge confirmed at ~0%—all capacity loss attributable to monitoring equipment.
3. Temperature Sensitivity
System-level coefficient of +1.0 ± 0.3 mV/°F (pack + measurement chain combined).
Safety Warning
⚠️ Lithium batteries carry inherent risks. This 500Ah bank can deliver thousands of amps in a short circuit.
- ✅ Always use Class T fuses at terminals
- ✅ Never charge below 0°C (32°F)
- ✅ Always use a BMS — architectural immunity does not replace cell protection
- ✅ Keep a Class D fire extinguisher accessible
Citation
@misc{collis2026lifepo4,
author = {Collis, William K.},
title = {LiFePO4 Battery Bank: Architectural Immunity \& Long-Term Storage Study},
year = {2026},
doi = {10.5281/zenodo.18452542},
url = {https://doi.org/10.5281/zenodo.18452542},
note = {GitHub repository: https://github.com/wkcollis1-eng/Lifepo4-Battery-Banks}
}
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Last updated: March 6, 2026 • Data through March 6, 2026
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