RCU Forums - View Single Post - Battery C rating question - Masters Pattern
Old 07-01-2016 | 12:36 PM
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ltc
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Originally Posted by philakapd
Amps = Volts / Ohms

EXAMPLE:

Fully charged, 5000mAh, 5s LiPo:

Amps = 21Volts (5s) / 1.1 Ohms (40C battery): 19.09 Amps

Amps = 21Volts (5s) / 1.3 Ohms (25C battery): 16.15 Amps


Power (Watts) = Volts x Amps

21 Volts x 19.09 Amps = 400 Watts (40C battery)

21 Volts x 16.15 Amps = 339 Watts (25C battery)

During a flight, the battery consumed 2500mAh and the 5s voltage is now 20 Volts. If you increase the mAh to 5400, the battery WILL have a higher voltage.

Amps = 20 Volts / 1.1 Ohms: 18.18 Amps (40C battery)

Amps = 20Volts / 1.3 Ohms: 15.4 Amps (25C battery)

20 Volts x 18.18 Amps = 363 Watts available using 40C battery

20 Volts x 15.4 Amps = 308 Watts available using 25C battery


Note the voltage is resting state and not under load


If the "C" rating is increased (lower resistance), the amount of energy available at the end of flight is increased.

If the mAh rating is increased (higher capacity), the amount of energy available at the end of flight is increased.


Go get the 5400/40C !!!!


Clear Skies and Happy Pattern Flying

-PD
Im curious where you got the 1.1 ohm and 1.3 ohm numbers.