elf232

Please help me understand how the C-rate relates to mAh, as an example: I have a device drawing a current of 700 mA, how do I know if 1C will be sufficient?

mandtra

My Feedback: (29)

you take the capicity of the battery and multiply by the c rating and that's the max amps that can be safely used.
example a 3s 2200mah battery with a 25c rating 25x2.2= 55 amps 25is the c , and the 2.2 is the capicity

elf232

Wait? where did 2.2 come from, the mAh of the battery?

mandtra

My Feedback: (29)

sorry i edited the post above. yes 2.2 is for 2200 mah. lets say your battery is only a 600mah and 2c it would be .6X2= 1.2 amps .6 is the mah , and 2 is the c rating

jdetray

Since you usually want your final answer in A (Amps), you must first convert the battery capacity from mAh (milliAmp-hours) to Ah (Amp-hours). To do that, you divide mAh by 1000. So 2200 mAh/1000 = 2.2Ah.

Once you have the battery capacity in Ah, multiply by the "C" rating to determine the maximum current the battery can provide.

So if you have a 2200 mAh battery rated at 15C, it can provide:
2.2 x 15 = 33 A

But if the 2200 mAh battery is rated at 25C, it can provide:
2.2 x 25 = 55A

Of course battery makers routinely overstate the "C" rating of their batteries. Or perhaps it is more accurate to say that they claim a "C" rating based on ideal conditions seldom encountered in actual R/C flying. So to avoid battery damage, it is advisable to de-rate the batteries a bit and run them at perhaps 80% of the claimed "C" rating.

- Jeff