The power system, battery to current
1.[1p] A 6S lithium pack is fully charged. With each cell at 4.2 V, what is the pack voltage, in volts?
A 6S lithium pack is fully charged. With each cell at 4.2 V, what is the pack voltage, in volts?
2.[2p] A 1300 mAh pack is rated at 100C. What is its maximum safe discharge current, in amps?
A 1300 mAh pack is rated at 100C. What is its maximum safe discharge current, in amps?
3.[2p] The main reason to build a craft at a higher cell count, such as 6S instead of 4S, is that
The main reason to build a craft at a higher cell count, such as 6S instead of 4S, is that
The answer is: the same power is delivered at lower current, so the wiring and ESCs run cooler
The answer is: the same power is delivered at lower current, so the wiring and ESCs run cooler
The answer is: the same power is delivered at lower current, so the wiring and ESCs run cooler
4.[2p] Voltage sag under heavy load happens because
Voltage sag under heavy load happens because
The answer is: the pack has internal resistance, and current through it drops voltage inside the cells
The answer is: the pack has internal resistance, and current through it drops voltage inside the cells
The answer is: the pack has internal resistance, and current through it drops voltage inside the cells
5.[3p] A quadcopter hovers at 9 A on a 5000 mAh pack. Using 80 per cent of the capacity as usable, roughly how many minutes can it hover?
A quadcopter hovers at 9 A on a 5000 mAh pack. Using 80 per cent of the capacity as usable, roughly how many minutes can it hover?
6.[2p] Resistive loss in the wiring grows with the square of the current, which is why the main battery leads are the thickest wires on the craft.
Resistive loss in the wiring grows with the square of the current, which is why the main battery leads are the thickest wires on the craft.
The answer is: True
7.[2p] A low-ESR capacitor is often fitted across the battery input because it
A low-ESR capacitor is often fitted across the battery input because it
The answer is: absorbs the voltage spikes the switching ESCs throw back down the leads
The answer is: absorbs the voltage spikes the switching ESCs throw back down the leads
The answer is: absorbs the voltage spikes the switching ESCs throw back down the leads