jre8655

I'm getting back into R/C flying, but going electric this time. I've run into a dilemma with battery specs.

I have an E-flite Apprentice that uses an 11.1v 3s 20c 3200mah Li-Po. I just bought an E-flite T28 Trojan that can use an 11.1v 3s 30c 3200mah Li-Po.

What's the difference between the 20c and 30c batteries?

Could the 20c be used in lieu of the 30c?

What would be the danger?

krzy4rc

My Feedback: (2)

No danger. You just may limit your current that the battery can provide. You should watch the heat and how warm your batteries get.

20C battery is 20 x 3.2A - 64 amps max output.
30C battery is 30 x 3.2A = 96 amps max output

I find it hard to believe either one of those planes are drawing that kind of current. I would be surprised if you have over a 30A speed controller.

As you get further along, when you size the batteries you use I like to increase the C rating such that I max out at 60-70% of the batteries capabilities. It taxes the batteries less and creates less heat. But, I really don't think you will have an issue with the planes you have.

I am running a 93 AJ Laser with a 160A ESC and two 6S 10000 mAh batteries in series. I max out at 130 amps. The batteries I use are 20C. That gives me a max of 200Amps, but I only use 130A max. I rarely have more than warm batteries (except whenits 100F and 95% humidity down here!)

All that said, depending on the batteries, you may get a little more powerful feel (especially towards the end of the flight) with a higher C battery (but they will also be a little heavier).

Last piece of advice is to watch your time and make sure you come down with 30% left in the battery. If you do that they will last a VERY long time.

Fly 'em and have fun,

jre8655

Rich,

Thank you very much for a very informative answer. I greatly appreciate it.

Jack

Rodney

The higher the C rating, the lower the internal resistance. Simply means less internal heat generated the higher the C rating. Also, as said above, the C rating tells you an approximate maximum current you should draw from the battery; i.e. C times capacity of battery equals the highest recommended current you should draw from the battery. Now, how C ratings are defined (at least to my knowledge) is not a standard definition; different companies may define them differently so they are not a guarantied quality.

Bcolici

Usually the 30c pack will weigh more as well. Check your cog when using different batteries.

jester_s1

From reading battery tests/shootouts and having owned a few lipos myself over the last 4 years or so, I really don't think C ratings mean much at all. They definitely aren't an objective standard that will let you compare batteries between brands. For example, a Turnigy 60C battery isn't better than a MaxAmps 40C battery. At best, C ratings will let you compare batteries within a manufacturer to get the performance you need. I don't know of any appropriately powered models that would go over 20c continuous current, so the ratings aren't useful for determining firm limits of power consumption. But on the higher performance models where you are only planning to get 5-6 minutes of full throttle flight time, you may see a power increase by going up to the next C rating level due to the lower internal resistance.