Nautical blog

Sizing your lithium battery bank for a sailboat — Skysat workshop method 2026

Choosing 200 Ah of lithium for a 40-foot sailboat is easy. It’s also probably wrong. The Skysat workshop method boils down to 5 steps: 24 h energy balance by load, simultaneity coefficient, safety margin, useful DoD, final capacity selection. Numbered examples for 30 / 40 / 50-foot sailboats in coastal vs offshore cruising. The right sizing costs 30 % more upfront and 50 % less in usage frustration.