Can someone help me settle a discussion. How is the C rating related to the mAh rating? Thanks.

The C rating is the maximum discharge rate for that battery pack under load conditions. THis is a "don't exceed" discharge rate number for that pack.


The mah or miliamps per hour is the capacity of that battery, or what it will take for a full charge.

So if I understand this LiPo stuff, a 11.1V, 1300mAh, 15C battery will last longer than a 11.1V, 1300mAh, 25C battery because the 25C rating is higher, thus giving it the ability to discharge itself faster. Or am I totally off...

Only if you decide to discharge it at 25C. That's the maximum discharge rate. The harder you push the motor, the more current it will draw. If you exceed 25C, for instance, (that's 25 times the battery capacity.. 1300 X 25= 32500 miliamps or 32.5 amps. Since the battery pack is not a 32 amp pack, well, it will not last very long at 25C. Over 25C and you will damage that battery pack.

Also, be careful where you charge those LiPo packs. Don't do indoors or in your car. Make sure you are outside and in the open. If it does catch fire, it can be pretty spectacular.


CGr

Copy that. I think I've got it now. Thanks for the info.

You need both the C rating and the capacity to tell you how much a battery CAN discharge.

2000mah 10C battery 2000mah x 10C=20000mah /1000 to convert to amps can give you 20 amps

A 3000mah 10C battery can deliver 30amps

Remember that with electrical systems, motors pull current, batteries don't push current. So lets say that you have a motor that is rated to 20 amps current, and you have a battery that can deliver 35 amps, then you are alright because the motor will only pull 20 amps under a proper load, which is well under what the battery is capable of supplying.

As said above.

In addition to all of that, you really do NOT want to push a battery pack more than you have to.

Ideally it would be advantageous to configure a plane so that you draw well below the C rating of the battery at say 80% throttle when this represents normal flight modes.

This will conserve the lifetime of the battery, but still give you a reserve.

Remember however that increasing the "C" rating does not equate to longer flight times.

If you want longer flight times, increase the mAh rating of the battery, which BTW also increases it's "C" rating too.

In your application a 25C 1300mAh battery will last just as long as a 15C 1300mAh battery.

Not correct, it increases the total amps that can be drawn from the pack, not how fast it can be drawn. In simple terms, maH of a battery is it's reserve and the "C" rating is how fast it can release that reserve.

Cheers

You're right I mistated it. Ugh.

The "C" rating can remain the same but the total number of Amps that can be pulled out of the battery will increase if you increase the capacity.