Big loads offgrid with a small battery (sidelined)
An off-grid cabin uses a generator for big loads like cooking and water pumping, keeping a small 100Ah battery for low-power electronics only, running the generator 30-60 minutes daily instead of investing in a large battery bank.
Background
- Joey Hess is a long-time free/open-source software developer best known for creating git-annex, a tool for managing large files with Git. He lives off-grid in rural Idaho and often writes about his solar-powered homestead setup.
- This post is about a practical problem in off-grid solar: large intermittent loads (like a water pump or power tools) can briefly draw far more current than the battery can deliver, even when the battery holds enough total energy. His DIY solution uses a "sidelined" battery—a small additional battery that handles these big transient loads while the main battery runs the home.
- The piece captures a recurring tension in off-grid tech culture: between ideal solutions (complex, expensive, "by the book") and pragmatic, jury-rigged ones that work well enough with what's on hand. Hess explicitly rejects automation and extra complexity in favor of a simple physical switch.