Lithium-ion batteries are widely used worldwide. Interestingly, there are different types of lithium-based batteries. Among them, lithium-polymer batteries are common in modern gadgets such as drones. However, these LiPo batteries have different C ratings, which often confuse customers. So they ask: What is the C Rating on a LiPo battery?
Remember, a C rating indicates how fast the battery can deliver the stored power to the gadget. In other words, it refers to a battery’s ability to deliver current during use. Each battery can have different C ratings. These include 0.5C, 1C, 2C, 20C and so on. Each of these C ratings has its meaning. In this article, I will discuss everything about the C rating and its meaning for LiPo batteries.
What Does “C Rating” Mean for LiPo Batteries?
The C rating, or discharge rating, indicates how quickly a battery discharges its stored energy. It does not indicate how much power a battery stores (capacity). In other terms, this refers to the current the battery delivers to the gadget without overheating it. A battery with a 1C rating means it will discharge all of its stored energy in one hour.
It is worth noting that the C rating is not directly related to the battery’s total charge-holding capacity. Suppose you have two lithium-polymer batteries with the same storage capacity of 4000 mAh. However, these batteries have different C ratings. Suppose Battery A has a 0.5C rating while Battery B has a 1C rating. Both have the same storage (4000 mAh).
Due to different C ratings, these batteries will discharge their stored power at different times. A 4000 mAh battery with a 1C rating will discharge in one hour. On the other hand, a 4000 mAh battery with a 0.5C rating will fully discharge in two hours. This means that these two batteries differ in how quickly they deliver power to the gadget.
Battery B with a 1C rating is better, as it can deliver high current to the gadget and discharge quickly. This is very useful when the battery powers a gadget that requires a higher current. The best examples include RC cars or drones. The C rating is generally printed on the battery’s labels and in its user manual.
クイックハイライト C rate indicates the discharge rate, but it is safe for the batteries. A higher C rating does not mean the battery will overheat due to higher discharge. Additionally, gadgets powered by these batteries also experience overheating. Each battery has its own C rating, and it delivers specific power without overheating or issues.
C Rate Chart of Batteries
It is worth noting that every C rate has a specific duration. For example, a battery with a C rate of 1C will discharge and get empty in an hour. On the other hand, a 0.5C battery will empty in 2 hours. By simply reading the C rating on the battery, you can understand how quickly it can deliver power and how quickly it drains. The C rate is inversely proportional to the duration it can maintain consistent power delivery to the gadget.
For example, a 1C battery can deliver power to the gadget for 1 hour. However, the 30C battery has a shorter discharge duration of just 2 minutes. Here is the C rate chart of batteries:
| C Rating | Discharge Time (hours) | Discharge Time (minutes) |
| 0.5C | 2 hours | 120 minutes |
| 1C | 1 hour | 60 minutes |
| 2C | 0.5 hours | 30 minutes |
| 5C | 0.2 hours | 12 minutes |
| 10C | 0.1 hours | 6 minutes |
| 20C | 0.05 hours | 3 minutes |
| 30C | 0.033 hours | 2 minutes |
This indicates that 0.5C lithium polymer batteries can last longer when powering the gadget. However, their maximum current-delivering capacity is lower. On the other hand, 1C, 2C, and 10C lithium polymer battery can drain quickly. However, their ability to provide maximum current to the gadget will be better. They will be able to power devices that require high current for their operations.
C rates indicating specific discharge time are based on LiPo batteries tested in laboratories. However, in real-life conditions, you might slightly deviate from the discharge durations. Why? That’s because of heat and other environmental factors. Additionally, older batteries with a 1C rating can last for 50 minutes instead of precisely 60 minutes. However, these ratings and their discharge rates are very similar, even in real-world scenarios.
How to Calculate the C Rating of a Lithium Polymer Battery?
As I said earlier, a C rating means the battery can continuously power the gadget at its maximum current. Suppose a 1C lithium-polymer battery that can power a device continuously for 1 hour. During this time, it will provide the gadget with specific current and keep discharging its power.
The maximum current the battery delivers during discharge is specified by the manufacturer. You can check it in the user manual or on the battery’s labels. Here is the formula to calculate the C rating:
C Rating = Maximum Current (A) ÷ Capacity (Ah)
Using this formula, you can calculate a battery’s C rating, including Lipo batteries. You can check both capacity and maximum current on the battery’s label. Suppose you have a battery with 5000 mAh capacity. To use the above formula, you will have to convert mAh into Ah. This means your battery capacity will be 5 Ah.
The maximum current it delivers to the gadget during use is 40A (ampere). You can use the formula above to find the exact C rating of that battery.
C Rating = 40 ÷ 5 = 8C
This means that your 5000 mAh battery has a C rating of 8C. This means your 5000 mAh battery can deliver a maximum of 40 amperes for 7.5 minutes. Simply put, your battery discharges in 7.5 minutes, and it empties in that time. You can find a battery’s C rating using the formula above. Remember, battery capacity and current are typically provided by the manufacturer.
Continuous vs Burst C Rating on LiPo Batteries
Continuous and burst C rating can be confusing, especially if you’re a beginner. These two actually are C-rated but indicate different current-providing ability of the batteries. For example, a continuous C rating indicates that a battery can provide a steady, maximum current for longer durations. This means the gadget will keep drawing the same (maximum) current for longer periods.
When the battery is empty, the current will drop to zero. This duration can be 1 hour, 30 minutes, or 10 minutes, depending on the C rating. In contrast, burst rating indicates the maximum current a battery can deliver for a very short period. The battery will provide the maximum current, then drain out.
However, it will remain safe as long as it provides the highest current required for device operation. Imagine you have a battery with 10/20 C ratings. This means its 10C is a Continuous C rating, while its 20C is its Burst C rating. This battery will provide 22 amperes for a longer duration (continuous C rating).
However, when high power is needed, this battery can deliver up to 44 amperes before emptying. This 44A will draw all the power from the battery immediately (for a very short span). If used at 22 amperes, the battery will last longer. This burst C rating is crucial when you need to give a high-current start device that requires more power.
Why is the C Rating of LiPo Battery Important?
The C rating is not a useless term. It has a big impact on the performance and safety of modern batteries. In fact, it helps users understand the battery’s capacity, so it is not abused or pushed beyond its limits. Here are some key advantages of a C rating in Lipo batteries:
- Power Demands & Efficiency
First of all, knowing the C rating helps us use the batteries appropriately. As you know, different devices have different power demands. Some of them have bigger motors that require more power. In such a case, you can use a battery with a higher C rating. Such a battery will provide higher current, enabling the device to operate. Batteries with a smaller C rating will be preferred for devices with lower power demands.
- Battery Lifespan
It is crucial to note that each lithium-polymer battery has its limitations. For example, 1C batteries will never be suitable for high-power-demanding devices. If you use 1C in high-end drones, your device will drain power more quickly. This will affect the lifespan of the lithium polymer battery. A rating helps you understand battery capacity, so you use it correctly and increase its lifespan.
- Safety & Heat Management
Heating is one of the most annoying issues with batteries, right? You can prevent this issue if you know the C rating. How? The reason is that the C rating indicates the maximum current the battery can safely deliver. By not using devices that draw more power than the battery capacity can supply, you can prevent overheating. Remember, when the battery delivers more current than its rating, it will overheat. This will ensure the long-term safety of your battery.
Applications of High C Rate LiPo Batteries
LiPo batteries with a higher C rate simply mean they are very powerful. They may not last long, but they deliver high current. Examples of such batteries include those rated 20C, 50C, 75C, and higher. These LiPo batteries are ideal for devices that require more power. Such devices get high current from these batteries and start working. Here is the table showing the application of LiPo batteries with a higher C rate:
| 申し込み | High C-Rate LiPo Battery |
| Racing Drones or FPV Drones | 75C–120C |
| RC Cars / RC Trucks | 50C–100C |
| RC Boats | 40C–100C |
| High-Performance RC Airplanes | 50C–100C |
| Power Tools (Cordless) | 30C–60C |
| Electric Skateboards | 20C–50C |
結論
Lithium polymer batteries are powerful despite being lightweight and compact. They have excellent energy density, meaning they can store large amounts of power. However, the C rating indicates how fast a battery discharges. LiPo batteries with a higher C rating deliver higher current to the device, and vice versa.
It is worth noting that these batteries use different C rates for various applications. For example, batteries with low C rates are used for powerful, smaller devices with lesser power demand. Conversely, LiPo batteries with higher C rates are used for running high-end drones and RC vehicles. In this article, I have discussed everything about the C rating and its meaning.