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RC Boat Runtime Calculator

Estimate ideal and usable battery runtime from capacity and average current draw.

Battery & Load

e.g. 0.8 leaves a 20% reserve.

Result

Estimated runtime
6.0min
at 0.80 usable capacity
Ideal runtime
7.5min

Ideal assumes the full pack; estimated applies your usable-capacity fraction.

Formula

  1. 1.Ideal Runtime (min) = Capacity (mAh) / (1000 × Average Current (A)) × 60
  2. 2.Estimated Runtime = Ideal Runtime × Usable Capacity Fraction

Worked example

  1. 1.Inputs: 5000 mAh pack, 40 A average, 0.8 usable.
  2. 2.Ideal = 5000 / (1000 × 40) × 60 = 7.5 min.
  3. 3.Estimated = 7.5 × 0.8 = 6.0 min.

Assumptions and limits

  • Real runtime varies with hull load, throttle habits and water conditions.
  • Calibrate average current from actual runs — this is an estimate, not a fuel gauge.

Related tools

Guides and concepts

FAQ

Why is my real runtime shorter?

Peak-load current spikes, aging packs and cold water all raise effective draw beyond your average figure.

Assumptions

  • Average current is constant over the run.
  • The usable fraction is yours to set — it is not a universal default.
  • Boat load, throttle style, temperature and pack condition all change real runtime.