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Old 02-23-2011, 01:58 AM   #1
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Default Yes, another lipo question lol

Would running two lipo's in parallel also double the c rating?
As in, running two 2s 5000mah 30c in series would be the same as running two 4s 2500 30c in parallel? Both would provide 16.8v at 150 amps?

Looking to pick up some batts for my erevo and figure it seems like I can probably stick two 4s batts in and wire for parallel instead of two 2 s in series. Thanks in advance.
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Old 02-23-2011, 02:16 AM   #2
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Yes they would both provide the same available power

Parallel doesnt double the 'c' rate just the size in mah (just becomes a 4s 5000mah 30c pack)

If you fit parallel 4s 5000mah packs you will double your runtime and available power

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Old 02-23-2011, 01:31 PM   #3
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Quote:
Originally Posted by badaml View Post
Would running two lipo's in parallel also double the c rating?
As in, running two 2s 5000mah 30c in series would be the same as running two 4s 2500 30c in parallel? Both would provide 16.8v at 150 amps?

Looking to pick up some batts for my erevo and figure it seems like I can probably stick two 4s batts in and wire for parallel instead of two 2 s in series. Thanks in advance.
Combining cells in parallel or series does not change the C rating of an individual cell. When you parallel a pair of lipos, that doubles the capacity, so paralleling 2 5000mah effectively become equivalent to a 10,000mah 2S lipo. Since capacity is part of discharge amps, the discharge amps doubles - but because the capacity doubled, not the C rate.

Two 2S 5000mah in series is the same thing as a 5000mah 4S. Two 2500mah 4S in parallel is the same thing as a 4S 5000mah. So yes, they are the same, the C rating does not change.

In parallel, capacity adds, voltage stays the same. In series, voltage adds, capacity stays the same. Neither changes the C rating. Since discharge amps = capacity(mah)/1000 X C rating, these two combinations have the same discharge amps. The series combo - 5000/1000 x 30 = 150amps, the parallel combo - 5000/1000 x 30 = 150amps.


I'm guessing you don't figure the capacity right for a parallel combination...
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Old 02-23-2011, 01:35 PM   #4
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Yeah, I didn't figure the c rating changed, mis wording on my part.

Not sure how you figure I didn't figure the discharge correctly though, as the example I provided was correct.

Anyways, just wanted to make sure my figuring was correct as it seems less expensive to order 2 4s lipos with a lower c rating and a lower mah than to order 2 2s lipos with a higher mah and c rating to get similar amperage and voltage.

Just to avoid confusion lol, I was planning on 2 x 2s 5000mah 25c, but am probably going to go with 2 x 4s 3000 20c. Only a 5a difference, and I should get slightly longer run time with the 2x4.

Thanks for the help.
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