What does a lipo discharge rate mean? - RC Groups
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Apr 03, 2009, 06:26 PM
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What does a lipo discharge rate mean?

Long time pilot but new to electric flight and love it. However, need to buy some 3 cell lipos but don't understand what they mean by discharge rate or the different ratings they give them for example 18C or 25C. If someone could explain this to me that would we great. Thanks.
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Apr 03, 2009, 06:57 PM
Surface, Air & Water Rc Toys..
freechip's Avatar
18C or 25C and what ever C rating 10-12-15-20-25-30C all represent the amount of amps the battery can safely deliver. C is Capacity.

1000mah or 1amp & 10C is battery capable of giving you 10a. Same 1000mah with a 25C rating is good for 25A

2500mah lipo 20C is 2.5A x 20, its good for 50A.

The C rating differs from manufacturers (they tend to give optimistic rating of their packs)

If you are using a 1500 20C pack for you're rc and after each flight or use the pack is very warm/hot, this is a sign that its running at close to and maybe more then its maximum rated amp draw. You can get a bigger C rated lipo say 1500C 30C. and you will notice a big difference in heat since its not working as hard to deliver the amps the motor requires.
Apr 03, 2009, 08:48 PM
Registered User
The C rating, times the amp-hour rating, represents the absolute maximum current that you should draw from the battery. So (for example) an 1800 mAh battery rated at 20C would be rated for 1.8*20 = 36 amps.
Apr 03, 2009, 11:56 PM
Registered User
Thanks. That helps a lot
Apr 04, 2009, 03:49 AM
old pilot
Ickarusmelt's Avatar
This is maybe more than you asked for, darken

It helps to understand what is going on with the electricity and hereís some more thoughts. Please chime in, guys, if this isnít right.

The charged battery has a herd of electrons waiting to go. The force they can produce is the voltage and depends on the design of the battery, 2S, 3S, etc. However, the size of the herd of electrons in the battery waiting to go, the mah, is like they amount of gas in the tank, regardless of the force it can produce.

When electrons move through conductors (all the electronic equipment in your plane) they produce heat, and amps per hour (how many electrons and how fast they move) determines the amount of heat. The C rating of the battery (how it is designed, and generally a bigger C rating is a little heavier) is how fast you can move the electrons out of it without generating too much heat. It you drain a lipo too fast, the heat will destroy it and this can get nasty.

The motor sucks the electrons out of the battery, and a small motor drinks them slow with less heat. A big motor sucks them faster and causes lots more heat in the battery. The battery C rating must be enough to handle how fast the motor will draw the electrons out of it.

Example: A buddy just had to fly his P38 (two Park 450 motors) one more time, and all he had left charged was a C15 battery. We all said don't, but he did anyway. Short flight was fine but the battery came out kinda round and he had to dispose of properly.

The esc amps rating is the same, how many electrons and how fast the motor will draw them through it. Too many electrons too fast will fry it.

The motor sucks the electricity, and make sure your battery C rating and esc amp limit will handle the current flow.

Happy electricity

Last edited by Ickarusmelt; Apr 04, 2009 at 04:05 AM.
Jun 06, 2009, 12:47 PM
Registered User

I need Help

I want to get the anx plane from hobby city but im having trouble on what C rating battery should i buy can anyone help me out with this..
Jun 06, 2009, 01:28 PM
Registered User
Originally Posted by fearlesshugo
I want to get the anx plane from hobby city but im having trouble on what C rating battery should i buy can anyone help me out with this..
Re-ask your question in the thread devoted to that plane. (I assume you're speaking of the AXN Floater-Jet.)

Jun 06, 2009, 02:05 PM
Registered User
In a perfect world, a 1000Mah battery with a 5C rating would be able to deliver 1 amp of current to the load for one hour before being discharged, 2 amps for 1/2 hour, 3 amps for a third of an hour, up to 5 amps for 1/5th hour or 12 minutes, without destroying the battery.

Of course, in the real world, there are losses to take into consideration, so the progression is not exactly linear, but things are pretty close. In the real world, if you were pulling 5C from the battery, the heat would probably cause other problems, and the useful time would be shorter. But it would still be pretty close. Of course, it would be far better to get a battery with more Mah capability in the first place, and run it at a lower "C" level ! Getting beyond 5C is getting into risky territory!

I realize that this is rather simplistic, but I hope this helps Jim S.
Last edited by jim_ag3y; Jun 07, 2009 at 06:34 PM.
Feb 26, 2010, 01:01 PM
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Kaolith's Avatar
will this esc (http://www.unitedhobbies.com/hobbyci...idProduct=6455) work with this battery(http://www.hobbyking.com/hobbyking/s...Product=6306)?
Feb 26, 2010, 01:08 PM
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Kaolith's Avatar
what would happen if the max current is 44 and the esc max amp is 15a?
Feb 26, 2010, 01:13 PM
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Kaolith's Avatar
Feb 26, 2010, 02:58 PM
Fly DW foamies!
appleflyer's Avatar
the ESC would fry. also this is a year old thread and just cause no one reply's in 12 minutes doesn't mean that no one is ever going to reply so you dont need to keep posting.
Feb 26, 2010, 03:07 PM
Wrend's Avatar
Feb 26, 2010, 10:39 PM
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Kaolith's Avatar
would the battery work with the esc? yes or no
Feb 26, 2010, 10:42 PM
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Kaolith's Avatar
or wold an esc with a max of 50a do better

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