Battery C Rate Calculator – Definition and Instructions

May 27, 2020   Pageview:74

Understating batteries is more than just knowing their brands, size, and perhaps application. For those who really want to get the most out of their cells, it is vital to dig deeper and get a better meaning of some of the numbers you see printed on them.

The most important factors to consider as the capacity, voltage, and the C-rating. When you know how to calculate them, you can always but specific batteries for specific uses.

Besides, you may have some applications that require more power than what the batteries can offer. In that case, you will need to know how much energy your device will use and how to get it.

The C rate is one of the most important aspects of understanding batteries. It helps you understand how long the batteries or battery bank will last while running the device you use.

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Low Temperature Large Current 24V Emergency Starting Power Supply Battery specification: 25.2V28Ah (lithium battery) , 27V300F (supercapacitor pack) Charging temperature:-40℃~+50℃ Discharging temperature: -40℃~+50℃ Starting current: 3000A

How is the battery C rate Calculated?

C rating is all about the amperage a battery can give out when considered for a specific function. It is important to get this calculation right in order to get the best performance.

Let's say you want to use a quadcopter build, and you can a 20C battery rated, 2000 mAh.

We can use the following formula to find out what such a battery can really do.

  • First convert mA into Amps: (2000ma) 1am/1000 ma = 2ma

  • Now we can calculate the c rating, which gives the total output of the battery:

2 x 20C = 40 Amperes

Hence, our battery can discharge 40 amps continuously and safely. Here is another reason you need to know the C-rating; it helps you protect the battery from damages that come from over-discharging.

Another approach to this calculation would be using Nanotech calculation. For instance, a 25c continuous, 50c burst battery can be used for the QAV250.

In this case, we can use the same formula as above to find out the safe amp output for the battery.

Firs convert the milliamps into amps;

  • (13000 am) 1am/1000ma= 1.3A

  • We can then determine the discharge rate as Amps x C rating.

  • 1.3ma x 25c = 32.5 Amp Discharge.

  • Now we can divide this figure by the number of motors on the device:

  • 32.5amp/4 = 8.13A.

Hence, if the quadcopter has four motors, each one of them will be drawing 8.13 Amos every time it is in use.

This means it is always critical to know the specifications of the device you are running the bettering with. It is all about getting the right battery for the application.

Today, Nanotech batteries have become very efficient in these applications. But of course, other better alternatives work just as well.

When you have crafts that draw more than 8.13 amps, you will need stronger batteries. Some of the maneuvers you may be taking them through may take so much energy. In this case, the last thing you want is to keep buying batteries after a short while because you did not do a good job in your research.

Apart from knowing how much energy the battery will be discharged, it is also a good idea to know how long the battery will take.

Late take the same example of a 2000mAh battery.

  • Let’s use a 0.5C rating

  • In this case, 2000mAh/1000 = 2A

  • 0.5C x 2A – 1A Available

  • 60/0.5C = 120 minutes charge/discharge

Note that, most batteries will come with C-ratings printed on their cover. This way, it is easier to know how long your battery will take to charge or to discharge.


What is C rate in a Battery?

The C rating is one of the most misunderstood aspects of batteries. Most users think it just a number on the batteries that show what the manufacturer offers.

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However, this figure shows the rate of time it will take to charge or discharge a battery. Also, you can also change this rate, either to be higher or lower, in which case, it will greatly affect how long it will take the battery to discharge.

In simple terms, C rating is all about how fast energy gets drawn from a battery while in use. The rate is often used together with the battery's capacity to calculate the maximum discharge.

When you are buying batteries for quadcopters, or other high-powered devices, Multi-rotors, and similar machines draw very high energy in their motors. You, therefore, don't want batteries that will handle such high currents.

Also, you need batteries that offer high-performance machines. There are so many batteries on the market today, and many of them will not give the performance you need.

It is important to also note that C rating is inversely proportional to the capacity of a given battery. If therefore, you increase capacity, you will have loved the C.

When building a new drone, understand the amount of amp the motor/prop combination can draw is very vital. It goes hand in hand with identifying max battery size, which can fit the device, whereas picking the right battery for the work.

What the instructions of the Battery C Rate Calculator?

The C rate calculator is a simple online tool that helps battery users identify the right batteries. There are many tools on the market, and each of them follows almost the same process.

Consider, for instance, a LiPo calculator. We all know LiPo is one of the best battery packs for those who want powerful batteries to run high-draining machines.

The C rating on these batteries is not very accurate. And this is why many people want to calculate the rating by themselves. The calculator uses the values of every cell in the pack. And you will need the real like C rating of the packs.

First, you will need the capacity of the cell in mAh. Second, you will need the internal resistance, abbreviated as iR, in milli O, of the cell. You will need an?ESR meter?to get this value.

Once you have these figures, insert them in the calculator as you will be directed, and then click on calculate. With that, you have your C rate.


Understanding the figures on your batteries can be a great step to getting the best performance. Now that you know how to calculate the C rating, you can pick the best batteries for your quadcopter or machine.

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