# C-Rate Explained

The Battery C-Rate refers to the rate at which a battery is charged or discharged. It is normally expressed in terms numbers that look like 1C, 2C, 0.5C or 0.2C.

The number in these expressions is simply a multiplier.

The letter C in those expressions in more easily understood if you think of it as simply the value of the Amp Hour rating.

*In truth, it stands for Coulomb (as in Charles Coulomb), but if you think of it in those terms, you’ll get yourself pretty confused.*

Like I said, think of C as being the equivalent of the value for the amp hour rating, thus for a 50 Amp Hour battery:

- 1C = 1 x 50 = 50 Amps
- 2C = 2 x 50 = 100 Amps
- 0.5C = 0.5 x 50 = 25 Amps
- 0.1C = 0.1 x 50 = 5 Amps

Put into context of battery manufacturers or engineers speaking of battery performance, you may hear:

“*When discharged at 1C, this battery will last 40 minutes. When discharged at .2C, the battery will last of 58 minutes*.”

**Translation:** If this were a 200 amp hour battery, it will last for 40 minutes if discharged at 200 amps and will last for 58 minutes if discharged at a rate of 40 amps.

or…

“*This battery is capable of receiving a bulk charge at 2C*“

**Translation: **If this were a 75 amp hour battery, you could apply a bulk charge at a rate of 150 amps.