# Battery Charge and Discharge Rate Calculator: C-rating To Amps

Use our battery charge and discharge rate calculator to find the battery charge and discharge rate in amps. Convert C-rating in amps.

## Battery charge and discharge rate calculator

Battery capacity
Battery C rating
C

Note: Use our solar battery charge time calculator to find out the battery charge time using solar panels.

If the C-rating is mentioned as C/n (any number), in this case, C = 1. (E.g, C/2 = 1/2 = 0.5C).

• C/2 = 0.5C
• C/5 = 0.2C
• C/10 = 0.1C
• C/20 = 0.05C

### how to use this calculator?

1 - Enter the battery capacity and select the unit type. For example, If you have a 50 amp hour battery, enter 50 and select Ah.

2 - Enter the battery c-rating number (mentioned by the manufacturer on the specs sheet of your battery).

Enter "Calculate" button to find out the results.

## where to find battery c rate?

Generally, you will find the battery c rate on battery label or on the specs sheet of your battery.

As you can see, the battery c rating is mentioned as "max. charge current" and "max. discharge current".

## Battery C rate chart

The below chart shows the conversion of different c-ratings on batteries into charge/discharge time.

## How to convert c-rating to amps?

Converting the C rate of your battery into amps will give you the recommended charge and discharge current (amps).

Formula: Battery charge and discharge rate in amps = Battery capacity (Ah) × C-rate

### example #1: 0.05C rate to amps

let's say you have a 100ah lead-acid battery.

• Battery capacity: 100ah
• C-rating: 0.05C or C/20
• C-rating in amps: 100ah × 0.05C = 5 amps

100Ah lead-acid battery has a recommended charge and discharge rate of 5 amps

### example #2: 0.5C or c/2 rate to amps

let's say you have a 100ah lithium battery.

• Battery capacity: 100ah
• C-rating: 0.5C or C/2
• C-rating in amps: 100ah × 0.5C = 50 amps

100Ah lithium-ion battery has a recommended charge and discharge rate of 50 amps

## How to convert c-rating to time?

Converting the C rate of your battery to time will let you know your battery's recommended charge and discharge time.

Formula: C-rate in time (hours) = 1 ÷ C-rate

Formula: C-rate in time (minutes) = (1 ÷ C-rate) × 60

### Example #1: 0.05C to time

• 1 ÷ 0.05C = 20 hours
• (1 ÷ 0.05C) × 60 = 20 × 60 = 1200 minutes

### Example #2: 0.5C to time

• 1 ÷ 0.5C = 2 hours
• (1 ÷ 0.5C) × 60 = 2 × 60 = 120 minutes

## don't charge or discharge your battery at a higher rate

The chemistry of battery will determine the battery charge and discharge rate. For example, normally lead-acid batteries are designed to be charged and discharged in 20 hours. On the other hand, lithium-ion batteries can be charged or discharged in 2 hours.

You can increase the charge and discharge current of your battery more than what's recommended. But, as a result, this will affect the charge or discharge time period.

Also, charging or discharging your battery at a higher rate will increase the temperature in the battery's internal cells, which will cause power losses. Doing this more frequently will decrease the battery charge holding capacity.

## lead acid and lithium battery c-rate chart

The below chart shows the c rating of lead-acid and lithium battery.