SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Jan 27, 2015, 02:46 PM
Crashes count as bonus points
buildcrashrepair's Avatar
United States, KS
Joined Jul 2013
255 Posts
Discussion
LiPo C rating with batteries in series

Just a quick question concerning LiPo's in series

So if I have 2 or 3 batteries in series, do the C rating of the batteries add on top of each other?

For example,

If I have 3 4s 4000mah 20c batteries in series to make a 12s pack, would that be the equivalent of a 12s 4000mah 60c battery?

Also, how would I wire 3 batteries in series?

Thanks,
Rob
buildcrashrepair is online now Find More Posts by buildcrashrepair
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 27, 2015, 02:54 PM
Registered User
Staffs, UK
Joined Nov 2003
10,941 Posts
The C rating belongs to the individual cells. It never changes however many of them you connect in series or in parallel. Any battery made out of 20C cells is a 20C battery.

Steve
slipstick is online now Find More Posts by slipstick
Reply With Quote
Old Jan 27, 2015, 03:23 PM
Registered User
Letchworth, Great Britain (UK)
Joined Jul 2004
12,192 Posts
When batteries are connected in series only the voltages add up; everything else stays the same. To get them in series you simply connect the + (red wire) from one battery to the - (black wire) of the next, for however many packs you want. Then the remaining - at one end of the "chain" and + at the other end are the two wires you connect to whatever device you want to power.

Some people use gold "bullet" plugs on their batteries to facilitate connecting them in series, with male on the - wire and female on the + wire. You then just plug one male into the next female. The big disadvantage of this setup is it means you could accidentally plug one male into its own female, creating instant smoke and sparks In my opinion it's best to make up a series harness with polarised connectors.
abenn is online now Find More Posts by abenn
Reply With Quote
Old Jan 27, 2015, 03:48 PM
characters welcome!
Mark Wood's Avatar
United States, CA, Bear Valley Springs
Joined Feb 2000
26,678 Posts
And if you series 20C and 30C packs, it's a 20C pack since the 20C is the lowest common denominator.

mw
Mark Wood is online now Find More Posts by Mark Wood
Reply With Quote
Old Jan 27, 2015, 03:56 PM
Registered User
Joined Oct 2009
1,398 Posts
Quote:
Originally Posted by slipstick View Post
The C rating belongs to the individual cells. It never changes however many of them you connect in series or in parallel. Any battery made out of 20C cells is a 20C battery.

Steve
We know the C rating of each cell doesn't change, what he was asking is if it can be added together when connected.

The answer is not when in series, but yes it can when in parallel.

ex 2 X 4S 2200mah 20C

each lipo is capable of 44amps (according to the manuf)
in parallel 4S 4400mah 20C -- the entire pack is now capable of 88amps (again in theory).
nighthawk0077 is online now Find More Posts by nighthawk0077
Reply With Quote
Old Jan 27, 2015, 04:23 PM
Y=C+I+G
cmdl's Avatar
United States, CA, Rosemead
Joined Jan 2012
9,517 Posts
that still does not change the C rating. you state it can change when in parallel.
cmdl is online now Find More Posts by cmdl
Reply With Quote
Old Jan 27, 2015, 04:28 PM
Registered User
Joined Oct 2009
1,398 Posts
No one said change, simply added together.
nighthawk0077 is online now Find More Posts by nighthawk0077
Reply With Quote
Old Jan 27, 2015, 04:29 PM
Y=C+I+G
cmdl's Avatar
United States, CA, Rosemead
Joined Jan 2012
9,517 Posts
that is the capacity that is added, not the C rating. the max discharge is a function of capacity and C rating and has only gone up because capacity has been added together.
cmdl is online now Find More Posts by cmdl
Reply With Quote
Old Jan 27, 2015, 04:31 PM
Registered User
Joined Oct 2009
1,398 Posts
Correct
nighthawk0077 is online now Find More Posts by nighthawk0077
Reply With Quote
Old Jan 27, 2015, 05:02 PM
Registered User
Staffs, UK
Joined Nov 2003
10,941 Posts
Quote:
Originally Posted by nighthawk0077 View Post
Correct
And therefore the C-rating hasn't changed. Just as I said.

Any battery made of 20C cells is ALWAYS a 20C battery. Parallel/series it makes no difference.

Steve
slipstick is online now Find More Posts by slipstick
Reply With Quote
Old Jan 27, 2015, 05:42 PM
Crashes count as bonus points
buildcrashrepair's Avatar
United States, KS
Joined Jul 2013
255 Posts
Guy thanks for the input!

So if I am understanding this right the C rating will only go up because the capacity of the pack has now been doubled/tripled.

So a 4000 mah 25c mah pack would have a max discharge of 100 amps. So if I were to put 3 of these packs in series I would have a 4000 mah pack but because there are 3 of them that would make a 12000 mah 4s pack so that would have a discharge of 300 amps?
buildcrashrepair is online now Find More Posts by buildcrashrepair
Reply With Quote
Old Jan 27, 2015, 05:51 PM
Y=C+I+G
cmdl's Avatar
United States, CA, Rosemead
Joined Jan 2012
9,517 Posts
max discharge ( = C x capacity) went up because capacity went up. C stayed the same.

in series you increase voltage (add cell counts), in parallel you increase capacity (add mah). in series, your max discharge stays the same since capacity stays the same.
cmdl is online now Find More Posts by cmdl
Reply With Quote
Old Jan 27, 2015, 05:54 PM
Registered User
So. Cal.
Joined Oct 2004
8,525 Posts
Quote:
Originally Posted by buildcrashrepair View Post
So if I am understanding this right the C rating current delivery capability will only go up because the capacity of the pack has now been doubled/tripled.
C rating (multiplier) stays the same. Ability to source current goes up by virtue of increase in capacity.
mrforsyth is online now Find More Posts by mrforsyth
RCG Plus Member
Reply With Quote
Old Jan 27, 2015, 05:55 PM
Registered User
Joined Oct 2009
1,398 Posts
Again the C rating would only go up as you describe when connected in parallel.
nighthawk0077 is online now Find More Posts by nighthawk0077
Reply With Quote
Old Jan 27, 2015, 09:36 PM
Registered User
Australia, VIC, Melbourne
Joined Feb 2010
1,832 Posts
Quote:
Originally Posted by nighthawk0077 View Post
Again the C rating would only go up as you describe when connected in parallel.
The C rating NEVER changes.

The amount of current it can source (C rating * capacity) will change if the packs capacity does.
desertstalker is offline Find More Posts by desertstalker
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question using Lipos with Different C rating in series???????????? tlh101 Batteries and Chargers 12 Nov 06, 2014 08:54 PM
Discussion Using 3 identical lipo in series with diffrent C-rating VRflyer Batteries and Chargers 4 Jun 19, 2014 07:54 AM
Discussion Can i connect a 3s and a s with exact same C rate and mah in series to make 5s paktazh Batteries and Chargers 3 May 07, 2014 12:47 AM
Discussion Capacitor in series with Lipo for higher burst discharge rating? jm82792 Power Systems 30 Mar 07, 2014 03:05 PM
Question Lipo packs in series, different C rating GoRgOyL Batteries and Chargers 3 Jun 18, 2010 11:30 AM