- Beyond Sustainability - The Case for Regenerative Design
- Understanding Place - Climate, Site, and Solar Geometry
- The Six Integrated Systems - An Overview
- Building with the Earth—Natural Materials
- Passive Solar Design - Heating and Cooling Without Machines
- Off-Grid Energy Systems - Power from the Sun
- Water - Catching, Storing, and Cycling
- Liquid Waste Treatment - Botanical Systems
- Food Systems—Buildings That Feed
- Community Design - Scaling Up
- The Integrated Design Process
- Appendix A: Glossary of Key Terms
- Appendix B: The Pangea Textbook Series
- Appendix C: Key Design Principles at a Glance
- The Regenerative Community Vision
- Site Assessment and Land Reading
- Land Use Law and Legal Frameworks
- Master Planning for Regenerative Communities
- Infrastructure Systems Integration
- Housing Typologies and Density Design
- Community Governance Structures
- Economic Models for Community Development
- Phased Development Strategy
- Community Resilience and Long-Term Stewardship
- Appendix A: Legal Entity Comparison Chart
- Appendix B: Community Design Checklist
- Appendix C: Glossary of Community Development Terms
Batteries store the electrical energy produced by the solar array during the day for use at night or during cloudy periods. Battery bank sizing depends on two factors: the building’s daily energy demand (which determines how much storage is needed for each day of no solar production) and the number of days of autonomy desired (typically 2 to 5 days, depending on the site’s climate and the criticality of the loads).
Lithium iron phosphate (LiFePO4) batteries have become the preferred choice for most off-grid applications in recent years, replacing lead-acid batteries as costs have fallen dramatically. Lithium iron phosphate batteries offer higher energy density, longer cycle life (3,000 to 6,000 cycles versus 500 to 1,500 for lead-acid), higher usable capacity (90 to 95 percent depth of discharge versus 50 percent for lead-acid), and faster charging. Their higher upfront cost is typically offset by their longer service life and higher usable capacity.
Battery bank voltage is typically 24V or 48V for residential and small commercial off-grid systems. Higher voltage systems are more efficient (lower current for the same power means smaller wire sizes and lower resistive losses) and are generally preferred for larger systems. The charge controller and inverter must be matched to the battery bank voltage.