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Old Feb 25, 2010, 05:37 PM
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Joined Sep 2008
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20C vs. 40C Watts at same discharge rate?

Given three exact batteries except the C rating...

1800mAh 4S Lipo Pack 20C
Constant Discharge: 20C (36A)
Peak Discharge (10sec): 30C (54A)

1800mAh 4S Lipo Pack 30C
Constant Discharge: 30C (54A)
Peak Discharge (10sec): 40C (72A)

1800mAh 4S Lipo Pack 40C
Constant Discharge: 40C (72A)
Peak Discharge (10sec): 50C (90A)

With the same discharge rate of 36Amp for each pack, would the 40C pack hold its Voltage better and offer higher Wattage?
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Old Feb 25, 2010, 06:44 PM
write2dgray's Avatar
Seattle, WA
Joined Dec 2006
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Theoretically, yes .
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Old Feb 25, 2010, 06:59 PM
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Challenger 413's Avatar
Dickinson, Tx.
Joined Sep 2004
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Adding to that...Depends a lot on the cells and if they can hold voltage under a load. It could be that a 25C pack that is better made (better cells) can hold higher volts under a load than a cheaper 40C pack...

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Old Feb 25, 2010, 08:04 PM
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Also if the packs C rating is correct, then the 40C pack won't get as warm as a 20C pack would at the same discharge rate. The 40C battery is supposed to have less internal resistance than a 20C pack.
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Old Feb 25, 2010, 11:28 PM
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Joined May 2009
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using acurately rated(neither over nor under rating) 40C and 20C packs:

at 20C discharge, you get roughly 5.6% more voltage and 11% more power from the 40C pack.

at 40C bursts, you get 12.5% more voltage and 26.6% more power from the 40C pack.
at 5C mild discharge, you get 1.3% more volts and 2.6% more power from the 40C pack.
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