- 1 Intro
- 2 What is Storage Voltage of Lipo Battery?
- 3 What is Voltage of Lipo Battery?
- 4 How to Charge Lipo Batteries?
- 5 Don’t let them stay fully charged for long periods of time
- 6 What is Discharge rate or C rating?
- 7 What is Lifespan of Lipo battery?
Drone technology has brought about a revolution in various industries and hobbies, providing enthusiasts with incredible aerial perspectives and opportunities. One critical component that powers these unmanned aerial vehicles (UAVs) is the LiPo (Lithium Polymer) battery. Understanding the LiPo battery’s characteristics, usage, and safety considerations is essential for both beginner and experienced drone pilots.
In this article, we delve into the world of drone LiPo batteries, aiming to provide a comprehensive understanding of their basic knowledge. By gaining this knowledge, you’ll be equipped to maximize the performance of your drone, ensure longer battery life, and most importantly, promote safe and responsible flying practices.
When it comes to lithium batteries, it’s important to know that they work a bit differently from other types of batteries. If you use up too much energy or try to charge them too quickly, you could cause permanent damage or even start a fire. That’s why it’s really important to keep an eye on how much energy is left in the battery during your flight. This will help you know when it’s time to land and make sure your battery stays healthy.
What is Storage Voltage of Lipo Battery?
Alright, so when you get a fresh lithium battery, it’s already got some charge in it. This charge is called storage voltage, which is basically when each battery is charged up to around 3.8 volts (don’t worry if you’re not a battery expert, we’ll get into more details later). This voltage is what keeps lithium batteries stable, so if there’s too much or too little energy in the battery, it’ll slowly start to lose its efficiency. That’s why it’s super important to either charge or use up the battery until it’s at storage voltage right after you’re done using it.
What is Voltage of Lipo Battery?
The usable voltage range of a standard Lipo battery is from 3.2V to 4.2V. Any voltage lower than 3.2V may cause permanent damage to the battery. Any voltage higher than 4.2V will significantly increase the risk of the battery catching fire.
Typically, you will start with a battery in a storage or 3.8V charge state, place it on a charger to charge the battery to 4.2V, and then begin flying until the battery voltage drops to a position within the range of 3.5V to 3.7V, depending on your battery’s friendliness and comfort. You may ask why not fly until the voltage drops completely to 3.2V? Well, you can, but this will put extra stress on the batteries, slightly shortening their lifespan. Typically, when you fly and give the drone a sudden burst of power, the battery will drop and the voltage will drop as the battery tries to provide all possible power. If the sudden voltage drop causes the battery voltage to drop below 3.2V, it will cause greater damage. In addition, many drone batteries are made up of multiple cells, and you don’t always know the exact voltage of each cell.
If you have a battery made up of six cells, they will not discharge at the same rate, and you may eventually get one cell with a voltage of 3.0V and another cell with a voltage of 3.4V. In this case, you may damage the battery or the entire battery. Therefore, it is recommended that you land when the voltage of each cell of the battery is 3.5V or higher. You may also notice that giving the battery some time to recover from hard work after landing will slightly restore the voltage, and your 3.5V battery may stabilize at nearly 3.6V or 3.7V per cell. Some people even stop flying at the right time, so their battery voltage for each cell is 3.8V, so they don’t have to do a storage charge after the flight. This will reduce your flight time, but it may be worth considering for you.
How to Charge Lipo Batteries?
The safest and least stressful way to charge a lithium battery is at a rate of “1C”, or one times the capacity. A 1C charging rate means that the battery will be fully charged in one hour (assuming you start with a fully discharged battery at around 3.2V). For example, if you have a 1000mAh lithium battery and you want to charge it at 1C, you would set your charger to 1 amp. If you have a 500mAh battery, you could set your charger to 0.5 amps. If you have a 1500mAh battery, you would set your charger to 1.5 amps, and if you have a 3500mAh battery, you would set your charger to 3.5 amps.
Many batteries will list a maximum charging “C” rating on their packaging, which will be much higher than 1C, but it’s best to charge them as slowly as possible.
Don’t let them stay fully charged for long periods of time
After charging a lithium battery, it’s best to use it “as soon as possible” and then restore the battery to its storage voltage when finished. This is because batteries that haven’t reached their storage voltage will degrade over time, and this damage is cumulative. For example, a battery that’s been fully charged for a month might greatly increase internal resistance when used, causing performance to decline and heat to increase. There isn’t a magic number for how long it takes to fully charge a lithium battery. Charging it 10 times in one day is the same as charging it continuously for 10 days. Or charging it for 1 hour 24 times is the same as charging it once a day. Generally, most people think it’s acceptable to let the battery fully charge for about a day.
They should be discharged to their storage voltage.
What is Discharge rate or C rating?
It’s well-known that lithium polymer batteries can quickly release a large amount of energy. This is the main reason we use them instead of other batteries like lithium ion. The higher the battery’s discharge rate or C rating, the greater the capacity they can continuously provide without damaging the battery. The accuracy of manufacturer’s battery C ratings is disputed, but it can be fairly certain that you can compare C ratings of similar batteries from the same manufacturer to know which battery can safely provide more power.
Most batteries also list a C burst rating. This is the amount of power the battery can provide for a quick burst or a few seconds without causing damage, and it will be higher than the battery’s continuous C rating. Having a good burst rating is very useful when you want to go full throttle quickly. But remember, if the power consumed by the motor exceeds the battery’s C rating, going full throttle for more than a few seconds may damage the battery.
Note:Lithium polymer batteries don’t like extreme temperatures
Heat and cold are enemies of lithium batteries. Allowing lithium batteries to become hot during use or especially during charging will damage them. On the other hand, low temperatures will reduce the performance of lithium batteries. If you do fly in cold temperatures, remember this. Before using in cold weather, try to keep the battery warm but not too hot. Once in the air, using the battery will help keep them a little warm, but you’ll notice that their performance won’t be as good as you’re used to. Their voltage will be lower and the voltage drop you feel when you push them to the limit will be greater. The end result is reduced power and shorter flight time.
What is Lifespan of Lipo battery?
The lifespan of a lithium polymer battery is limited. Eventually, after about 300 charging cycles, you’ll find that the performance of most lithium polymer batteries has degraded significantly and it’s time to retire them. You’ll notice that your flight time is getting shorter and not as “fierce” as when the battery was new. Another indicator that a battery is ready to be retired is “swelling.” Batteries that are worn or abused will expand or swell when the internal components become gas. Finally, if your battery charger can measure the internal resistance of the battery, keep an eye on these numbers. A sudden jump or an internal resistance of one battery that’s much higher than the other batteries indicates that the battery should be retired.
However, their duration and number of cycles will depend largely on how friendly you are to them, not overcharging/undercharging them, keeping them at storage voltage, and not letting them get too hot.