Tools · Field ops

Battery Runtime

Will the battery last the activation? Capacity, current draw, and duty cycle in — honest hours out.

Typical: HT 0.15 · QRP rig 0.3–0.8 · 100W rig 1–2

Typical: HT 1.5 · QRP 2–3 · 100W SSB ~18–22

Casual ragchew ~20% · running a pileup ~40% · calling CQ endlessly ~50%+. SSB/CW average far below key-down current; FT8 runs near 50% duty by design.

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  • Usable capacity ≠ rated capacity. Draining lead-acid past 50% shortens its life dramatically; LiFePO4 happily gives ~90%.
  • Radios cut power or misbehave as voltage sags — a "12V" SLA under load on a 100W rig can drop below the rig's cutoff well before the math says empty.
  • Cold weather steals capacity: figure 20–30% less on a freezing summit.
  • Dropping from 100W to 50W barely costs you signal (half an S-unit) but nearly doubles transmit runtime.