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Old Apr 02, 2013, 07:35 PM
Registered User
Canada, NL, Corner Brook
Joined May 2011
158 Posts
C rating on batteries, does it matter if the c rating is way above the amp draw?

Does it matter what C rating your battery is? I mean i know most esc's require 20-30c
My question is can i Run my Turnigy 9xr with a 1300mah 25c 3 cell?

If the esc or motor isnt drawing over 20c current, than using say a 40c battery wouldnt make any difference because it only draws at 20 c, but this battery can handle up to 40c with say a 80c burst?

Basically will the C rating hurt my electronics if its rated way higher than what is suggested.
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Old Apr 02, 2013, 07:50 PM
Zero Expo
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San Diego, CA
Joined Mar 2009
792 Posts
The idea that an ESC requires a certain C-rating is nonsense.

Higher C-rated batteries are usually larger, heavier, more expensive, and tend to not tolerate storage as well.

In a transmitter, lower C-rated batteries are much better; using a NiMH battery is almost always the best option.
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Old Apr 02, 2013, 11:02 PM
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USA, GA, Marietta
Joined Aug 2005
6,328 Posts
ESC's are rated in amps. C ratings apply to batteries. The C rating of a battery specifies the maximum current the battery can safely supply. Your 1300mah 25c 3 cell will deliver 32.5 amps. If your ESC is rated higher than 35 amps you are safe.

I suggest you read this for a good explaination of RC electrics.

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Old Apr 02, 2013, 11:37 PM
Space Coast USA
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Space Coast
Joined Oct 2000
21,402 Posts
Adding to Glen's comments.....
The rating of the ESC just has to be about 25% higher than the max current draw of your motor.
Doesn't matter if the battery can supply 1000A, if the motor only draws 12A max, you only need a 15A ESC.
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Old Apr 03, 2013, 01:09 AM
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Canada, NL, Corner Brook
Joined May 2011
158 Posts
Thanks guys I get it now
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Old Apr 03, 2013, 03:59 AM
Registered User
Letchworth, Great Britain (UK)
Joined Jul 2004
12,336 Posts
Like hoppy has said, doesn't matter if your battery can supply more amps than the motor wants ... in fact it's good because the battery is less stressed. The only downside is that bigger battery (more amps capability) will cost more and weigh more.

When you're talking about the battery's amps capability, it's good to remember that it's Ah multiplied by C rating, so increasing Ah capacity, instead of or as well as C, will also increase the amps capability, with the added benefit that it also increases flight duration.
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Old Apr 03, 2013, 11:08 AM
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Joined Aug 2004
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The higher the C rating, the lower the internal resistance of the battery is where low internal resistance is desireable. Your ESC could not care less about what the C rating is as long as it can get the current required.
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