HB3YAQLucerne
Battery runtime
Runtime from usable capacity and receive/transmit current.
HB3YAQ · Ajdin HadzicLearning to take awayhttps://hb3yaq.ch/en/tools/battery
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Formula & context
Iavg = Irx(1 − D) + ItxD; t = Ah · u / Iavg; E = Ah · u · U
Duty cycle weights receive and transmit current. Enter the usable fraction yourself: it depends on the battery, discharge limit and operating conditions.
A worked example
10 Ah, 80% usable, 0.5 A RX, 5 A TX and 20% transmit duty yield 1.4 A average and about 5.71 hours.
Assumptions & limits
Constant-current approximation. Temperature, ageing, Peukert effect and converters are not modelled. Include auxiliary loads in the current values.
Estimating battery runtime realisticallyUnderstand the reasoning →From reading to experimenting
Battery runtime
10 Ah, 80% usable, 0.5 A RX, 5 A TX and 20% transmit duty yield 1.4 A average and about 5.71 hours.
Open example with starting values →Nominal capacity: 10 Ah · Usable fraction: 80 % · Receive current: 0.5 A · Transmit current: 5 A · Transmit duty cycle: 20 % · Nominal voltage: 12.8 VBack to the learning article →Then change exactly one value. Compare the result and use the formula to explain why it changes. The model limits below the calculator also apply here.