C Rating

C rating is a battery's claimed discharge capability expressed as a multiple of its capacity: multiply the two and you get amps. A 5000mAh pack labeled 100C claims 500 amps continuous — the manufacturer's claim, not a measured figure.

Also called:

C rate, discharge rating

In practice

The arithmetic isn’t in dispute. Battery University’s baseline: a 1Ah pack at 1C “should provide 1A for one hour.” Thunder Power says it the RC way — “C rating is discharge rating. This value could be multiplied by the amp hour of the battery” — and works a 3000mAh 20C pack out to 60A. Now a real label: Reedy sells a Zappers DR at “7200mAh 130C,” which multiplies out to 936 amps. Nobody measured 936 amps; that is arithmetic from the definition, not a bench result. Thunder Power separately defines burst C as the draw a pack handles “up to 5 seconds” — their definition, not an industry standard. ROAR’s 1/10 electric battery spec regulates only cell count, 8.40V and LiPo type — it sets no C-rating limit.

Why it matters

Treating a printed C rating as a measured spec is how racers overpay for a pack that performs no better, because neither the label nor the RC rulebook guarantees the number was tested.

Go deeper

Read the full post:

RC Motor Timing and LiPo Care: Where the Speed Actually Comes From

Sources

BU-402: What Is C-rate? — Battery University — reference definition of C-rate as a discharge multiple of capacity, with the 1Ah-at-1C-for-one-hour baseline.
FAQ — Thunder Power RC — battery maker defining C rating as capacity times the multiple, the 3000mAh 20C = 60A example, and burst as the draw handled up to 5 seconds.
Reedy Zappers DR batteries — Team Associated — manufacturer product listing showing a real printed label, “Zappers DR 7200mAh 130C 7.6V.”
ROAR Rule Book (PDF) — ROAR — 1/10 electric class battery specification listing only cell count (max 2s), 8.40 V maximum and LiPo type.