Lipo Battery, its full name is lithium polymer battery, people also called Li-po battery, or more correctly lithium-ion polymer battery (abbreviated as LiPo, LIP, Li-poly and others). Lipo is a rechargeable battery of lithium-ion technology using a polymer electrolyte instead of a liquid one.
Unlike lithium-ion cylindrical and prismatic cells, which have a rigid metal case, LiPo cells have a flexible, foil-type (polymer laminate) case, so they are relatively unconstrained.
High conductivity semisolid polymers form this electrolyte. These lipo batteries provide a higher specific energy than other lithium-battery types. It is a newer type of battery now used in many consumer electronics devices. They have been gaining in popularity in the radio control industry over the last few years, and are now the most popular choice for anyone looking for long run times and high power.
A battery is constructed from rectangular cells which are connected together to form the battery. A cell which can be considered a battery in itself, holds a nominal voltage of 3.7V. By connecting more of these in series, the voltage can increase to 7.4V for a 2 cell battery, 14.8V for a 4 cell battery and so on. By connecting more batteries in parallel the capacity can be increased. Often you will see numbers like 3S2P, which mean the battery as 4 cells (4S) connected in series, and there are 2 cell sets connected in parallel (2P) , giving a total number of 6 individual sells in the battery. So the number of cells is what defines the voltage of the battery. Having a higher voltage means the battery can provide more power to drive bigger motors, however more power does not necessarily mean the battery will provide energy for longer, that is defined by the battery capacity.
The trusty lithium-ion battery is the old industry workhorse. The development of the technology began all the way back in 1912, but it didn’t gain popularity until the adoption by Sony in 1991. Since then, lithium-ion batteries have powered a wide range of gadgets, from portable cameras to music players and smartphones.
Lithium-ion has proven so successful due, in part, to its very high energy density, lack of the “memory effect” (where cells become more difficult to charge over time) unlike previous battery tech, and its comparably cheap cost of production.
These batteries are constructed from two positive and negative electrodes separated by a liquid chemical electrolyte, such as ethylene carbonate or diethyl carbonate. The chemical composition of this battery limits it to a mostly rectangular shape. Lithium-ion battery capacity decreases over charge cycles and even discharges when not in use, which isn’t ideal. Worse though, the chemical electrolyte can become unstable at extreme temperatures or if punctured, leading to “thermal runaway” and fires. Although I should stress this is very, very rare. Electronic controllers are often used to regulate charging and discharge power to prevent overheating.
Lithium-polymer battery technology is newer than lithium-ion. It didn’t appear on the scene until the 1970s and has only made its way into smartphones much more recently. The technology has become increasingly popular in smartphones that make use of very fast charging technologies. This is because Li-Poly batteries tend to be a bit more robust than Li-Ion
Lithium-polymer technology again uses a positive and negative electrode, but with a dry solid, porous chemical, or gel-like electrolyte, rather than a liquid. As a result, polymer batteries can offer a lower profile, flexible, and more robust designs. As they, they also have a lower chance of leaking electrolytes resulting in thermal run away. In a nutshell, they’re a fair bit safer. However, they aren’t completely immune from issues arising from being punctured, stressed, or overheated.
A major drawback of this technology is a notably higher manufacturing cost, which means more expensive gadgets and smartphones compared to Li-ion. The lithium-polymer life cycle is also shorter and the batteries store less energy than the same sized Li-ion. This isn’t so ideal if you want your product to last a very long time. These cells also still use protection circuits to keep voltages operating within safe limits too.
A LiPo cell has a nominal voltage of 3.7V, and a lipo cell = 1 cell = 1S = 3.7V. For the 14.8V battery above, that means that there are four cells in series (which means the voltage gets added together). This is sometimes why you will hear people talk about a “4S” battery pack – it means that there are 4 cells in Series. So a four-cell (4S) pack is 14.8V, a three-cell (3S) pack is 11.1V, and so on.
3.7V battery = 1 cell x 3.7V= 1S battery
7.4V battery = 2 cells x 3.7V= 2S battery
11.1V battery = 3 cells x 3.7V= 3S battery
14.8V battery = 4 cells x 3.7V= 4S battery
18.5V battery = 5 cells x 3.7V= 5S battery
22.2 V battery = 6 cells x 3.7V= 6S battery
29.6 V battery = 8 cells x 3.7V= 8S battery
37.0V battery = 10 cells x 3.7V= 10S battery
44.4V battery = 12 cells x 3.7V= 12S battery
The voltage of a Lipo battery pack is essentially going to determine how fast your vehicle is going to go. Voltage directly influences the RPM of the electric motor (brushless motors are rated by kV, which means ‘RPM per Volt’). So if you have a brushless motor with a rating of 3,500kV, that motor will spin 3,500 RPM for every volt you apply to it. On a 2S LiPo battery, that motor will spin around 25,900 RPM. On a 3S, it will spin a whopping 38,850 RPM. So the more voltage you have, the faster you’re going to go.
When you select lipo battery, you need to know your motor of rc model, Voltage has an impact on motor, and motor influence the speed. The higher voltage is, the higher power( P) of the motor is, and here is the formula:
P=U*I
“P” is power, “U” is voltage, “I” is current. As you know, the voltage influence the power of the motor of battery, and the power has an impact on the RPM of the motor, that means speed. So in some racing, pilots need the batteries are of high voltage to meet the needs of their rc model to get a high burst.
The 1300mAh on the picture means the capacity of the lipo battery. Capacity is used to measure how much power a battery can hold.and the unit of capacity is milliamp hours (mAh), which means 1300mAh can be put on the battery to discharge it in one hour. Milliamp also can be converted to amps(A), here is the conversion:
1300mAh=1.3 Amp Hour(1Ah)
Generally, capacity can determines how long you can run before you have to recharge. A larger capacity pack may give you longer flight times but being heavier it will adversely affect performance. But it`s also influenced by the speed, the more quick you can flying your plane, the less time your flight time is. Because high speed means you need more power to drive your plane or others, so your power lost quickly.
Discharge Rate ("C" Rating) is simply how fast a battery can be discharged safely. In the RC LiPo battery world it is called the “C” rating. A battery with a discharging rate of 95c, that means you could safely draw it at the 95 times more than the capacity of the pack, a 10C pack = 10 times more, a 20C pack = 20C times more, from above the picture, you can discharge at 95 times more than 1300mAh, here is the calculation below:
95C = 95 x Capacity (in Amps)=95*1300mAh=123500mAh=123.5Ah
From the theoretical stand point, if you discharge you battery at a 2600mAh, so the 1300mAh of battery pack can be exhausted in half an hour. From above the calculation, draw battery at 123.5Ah, so this battery pack will be draw out in 0.63 minutes.
Sometime, you would be required to get a battery of high discharging rate, usually in a race, such as FPV racing, you must in a high speed and win a race. So the higher “C” rating means your thing can get a higher burst in a moment. So, you know, why so many pilots attach such a great importance into the high discharge rate. But the disadvantage of the high “C” rating is it may get heavier and affect its performance. And it may more expensive than the lower one.
The 1300mAh on the picture means the capacity of the lipo battery. Capacity is used to measure how much power a battery can hold.and the unit of capacity is milliamp hours (mAh), which means 1300mAh can be put on the battery to discharge it in one hour. Milliamp also can be converted to amps(A), here is the conversion:
1300mAh=1.3 Amp Hour(1Ah)
Generally, capacity can determines how long you can run before you have to recharge. A larger capacity pack may give you longer flight times but being heavier it will adversely affect performance. But it`s also influenced by the speed, the more quick you can flying your plane, the less time your flight time is. Because high speed means you need more power to drive your plane or others, so your power lost quickly.
Correct motor and propeller selection is very important to reduce the load on the ESC and to reduce motor saturation. Incompatible combinations can result in reduced overall performance, reduced system lifetimes due to excess heat and even ESCs burning out. If the prop and motor combination draw more than the ESCs nominal current rating at a static load, they are not recommended.
|
Cell Count |
Recommended Kv |
|
6S |
500-700Kv |
|
8S |
400-600Kv |
|
10S |
350-450Kv |
|
12S |
300-400Kv |
In order to use larger propellers, either the motor Kv or battery cell count should be reduced.
We are completing our 3d printed commercial drone ser#1 this week it's (march 2021)
Different Props will be tested, drone ser# 2 in build has different motors so there will be details on that run and analysis also
1. Never fly beyond the operating range of temperatures. If you haven't noticed, the batteries get really hot after a flight and if you think you can push it by a couple of degrees, just don't The battery temp when you take it out will probably increase by 2 or 3 times that amount since the heat sink on the drone can radiate so much heat. Similarly....
2. Don't fly with warm batteries. Fly with room temperature batteries. You don't want to risk overheating the drone/battery. This means that you should not charge a battery and immediately put it in the drone and take it up. No matter how cold it is (unless it's like close to freezing), your battery will only increase in temperature during flight.
3. Never charge batteries immediately after a flight. Notice how batteries warm up after a charge? You want to wait until the batteries reach room temperature before charging. And remember, even if the outside is cool to the touch, the inside might still be warm. I would recommend a good 1 hour at least before you charge up your batteries.
4. If you don't plan to use a battery within 1-2 days, I would recommend charging it to 50%. No swelling and in case you don't fly it for longer, you won't have to worry about it. Furthermore, you can just top it off to 100% the morning or night before you want to fly, and since you're only charging it for 50%, the battery won't heat up as much.
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