Mar 13, 2009, 12:09 PM Registered User Joined Feb 2005 616 Posts Question Difference Between 20c and 25c Ratings On Lipos? Hello, I am wondering what the difference is between a 20c and 25c rating on lipo batteries. I own both and it seems the speed of the airplanes are the same, so what is the difference then? Is it the take-off power maybe? Thanks for your help
 Mar 13, 2009, 12:28 PM Registered User Staffs, UK Joined Nov 2003 11,856 Posts The C-rating only tells you the maximum current you can (in theory) get from the battery. E.g. 2000mAh 20C battery = 40A max, 2000mAh 25C battery = 50A max. If your motor is taking a lot less than that e.g. 20A you will not see any difference at all in performance between the two batteries. Steve
 Mar 13, 2009, 12:34 PM Space Coast USA Space Coast Joined Oct 2000 22,285 Posts In a perfect world, The maximum continuous current delivering capability of a battery can be determined by multiplying the C-Rate X (mah of battery). A 2000mah, 20C battery would be capable of delivering 40000ma (40A). A 2000mah, 25C battery would be capable of delivering 50000ma (50A). That's in a perfect world - however, there are no standards for how a manufacturer/vendor decides how to C-Rate their batteries. The big boys like Enerland probably do a good job of accurately descrbing the C-rate. Other pack makers may be another matter. They may call a real 15C pack a 25C pack in order to sell more. You just have to go by the RCG reports on the packs to get some idea on how accurate the C-rate is. The other side of the coin is flight time. To get a 10 min flight, the average C-Rate draw needs to be 6C. A 20C pack operated at 20C will last a max of 3 min flight time and you'll maybe get 50 cycles out of it at the best. For me, high C-rates (>15) have no value as I want at least 8-10 min flight time. However, I'll take them if the price differential is small as it generally means a battery with a lower IR.
Mar 13, 2009, 12:58 PM
Air, Ground & Water
Joined Aug 2008
27,438 Posts
Quote:
 Originally Posted by Bookstar75 Hello, I am wondering what the difference is between a 20c and 25c rating on lipo batteries.
25-20=5 thats the difference.

You will probably not see any difference with you're eyes. But you would see it in tempatures.

If you're lipo is running hot after each use, then move up in C rating and you will see a difference because they will be able to handle more current and inturn work less hard. THATS IF THE C RATING FROM COMPANY IS GOOD.
 Nov 11, 2015, 01:49 PM Registered User Joined Nov 2015 3 Posts Hi, I have this quadcopter (http://www.amazon.com/UDI-U818A-2-4G.../dp/B00D3IN11Q). It came with a 3.7V 500mAh 20C LiPo battery. It gives a flight time of 8 minutes. Can I change the battery to 3.7V 1000mAh 25C LiPo battery for longer flight time? Will that affect the quadcopter?
Nov 16, 2015, 11:43 AM
Registered User
United States, WA, Woodinville
Joined May 2014
2,876 Posts
Quote:
 Originally Posted by robobala92 Hi, I have this quadcopter (http://www.amazon.com/UDI-U818A-2-4G.../dp/B00D3IN11Q). It came with a 3.7V 500mAh 20C LiPo battery. It gives a flight time of 8 minutes. Can I change the battery to 3.7V 1000mAh 25C LiPo battery for longer flight time? Will that affect the quadcopter?
You realize you resurrected a 6 year old thread?

A larger battery will be heavier and require more power to lift. There is a narrow range of battery sizes that will result in optimal flight times for a multicopter. Lift is 100% produced by power, so adding more weight to get more power requires it to consume more power to lift.
 Nov 16, 2015, 12:08 PM Space Coast USA Space Coast Joined Oct 2000 22,285 Posts 20C, 25C, 30C, 70C doesn't make much difference in a vehicle that flies for 8 min. Experiment! What is the difference in weight between the 500mah and 1000mah packs? Add that much weight to the copter as is and see how much the flying time is decreased. Rough calculation - Flying time with 1000mah pack will be 16min minus the time reduction you determined above.