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What does the formula tell you?

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What does the formula tell you?

Old 06-14-2013, 01:47 PM
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c130nut
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Default What does the formula tell you?

I have been out of electrics for a few years and am trying to remember what a particular formula tells you. I think it was the amp rating of the battery times the C rating then divide by 1000. Like 2200*30C= 66000 > 66000/1000=66 Is this the max amps that battery can discharge or the ESC rating I need?
I just cannot remember, but I am trying to re-rig an old Great Planes Siren hotliner.
Thanks
Old 06-14-2013, 02:12 PM
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Default RE: What does the formula tell you?

C means "capacity" and the number is a multiplier. It can a number of currents (amps) such as recommended charge rate , max charge rate , burst discharge rate , max constant discharge rate, ect. Most times when we use the phrase "C rate" we are describing the maximum constant discharge rate by the cell manufacturer. I think that's what you're after and those ratings many times are grossly inflated when using a pack in a plane.

For a 2.2 pack that is listed as a 20C it is then 2.2x20=44 amps.
For a 2.2 pack that is listed as a 5C it is 2.2x5=11 amps.
Old 06-14-2013, 02:32 PM
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c130nut
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Default RE: What does the formula tell you?

Ahhh... I found it...

A 2200mAh 10C battery is rated to be discharge at up to 22A (10 x 2200mA/1000) and the same size 12C battery would be good for 26.4A (12 x 2200mA/1000).

http://www.rcgroups.com/forums/showthread.php?t=739069

Thanks for the info! I knew I had seen it somewhere before.
Bill R.


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