The 10-year battery target — what it means in milliamp-hours

Translating Battery Life into Engineering Budget

A "10-year battery life" target translates into specific engineering constraints. Step 1: identify the battery. A typical AA lithium primary cell (Energizer L91, for example) stores 2400-3000 mAh at room temperature. Derate for cold operation, self-discharge over the deployment lifetime, and end-of-life reserve — typical usable energy is 70-80% of nominal, so 1700-2400 mAh per cell. Step 2: budget over the deployment lifetime. 10 years × 365 days × 24 hours = 87,600 hours. With 2 AA cells in series providing 5000 mAh nominal (or ~3500 mAh usable), average consumption must be 3500/87600 ≈ 40…