To Choose a LiPo Battery – FPV Batteries

The LiPo Battery in RC FPV

Even with the best FPV gear on the market, you won’t get very far without a decent knowledge of batteries and how to get the most out of them. The choice of batteries depends on the type of FPV aircraft and the flying characteristics of the pilot. Almost all FPV aircraft use Lithium-Ion (LiPo) batteries for power. LiPo batteries used in the RC hobby have similar characteristics to the batteries that power your smart phone, computer, and other small electronic gadgets. However, RC car batteries lipo have a different sort of covering over them, a flexible wrapper, rather than a rigid container. This saves on weight, and makes them an ideal choice for RC aircraft.

LiPos typically have identical cells inside them that are connected to make up the desired total voltage. Each cell is typically 4.23 V fully charged, and can be discharged down to around 2.7 V, but usually no less than 3.2 V in practice. It’s important not to discharge LiPos all the way because they won’t hold a recharge. You can find out more about the design and history of LiPos by visiting the lithium polymer battery Grepow’s facebook. Let’s focus on just the basics and on how to identify and read a LiPo battery label.

LiPo Battery Basics

The battery capacity rating (usually measured in milliamp-hours [mAh] or amp-hours [Ah]) is how much energy a battery can store. Similar to the size of a fuel tank, a battery with a higher mAh rating will last longer on a single charge. A 1000mAh or 1Ah battery can produce 1 amp of current for 1 hour. The discharge rate of a multirotor is much higher than 1 amp, so a more realistic example would be a 2200mAh lipo battery can produce 12 amps for 10 minutes, while a 3000mAh 4s lipo batteries can produce 12 amps for 15 minutes.

Voltage and Number of Cells

Both the batteries above have three cells and are termed 3s. Since each cell is 4.23 V, the total battery voltage is 3 * 4.23 V = 12.69 V. For more power, you could use a 4s battery, with a total voltage of 16.92 V.

What is the difference between 2s and 3s lipo battery?

A 2s LiPo battery has the same relative voltage as a 6s NiMh or NiCad type battery that is 7.4 volts. Running a 3s LiPo battery will give you the relative equivalent voltage as running 9 to 10 NiMh or NiCad cells. Be sure that your speed control is capable of running this higher voltage or damage may occur. Electric motors are capable of running different amounts of voltage. However, more voltage can and most likely will generate more heat in the motor. You will get much higher speeds, but you are starting to push the limits of the motors.

They wind up giving you the same run time, but the 3s 1300mah lipo has a much higher voltage output to the motor, so you wind up with more overall power, or watts, than you would with a 2s lipo batteries.

For arguement, you would probably be able to run the 3s at a lower throttle setting (less amps) than the 2s to get the same performance, since the voltage is higher, leading to more watts. So I would suppose the 3 cell might actually give you a little longer run time. Depending on how much throttle you need. Using the example above, you could run the 3s set up at about 2/3 the throttle, or 6.6 amps and still match the 2s in terms of watts.

Ok, the following are two products about 2s and 3s lipo from Genstattu.com

2250mAh 3s 35c Lipo Battery

Gens Ace lipo batteries provide you with great performance for your multi-rotor air-frames and planes. This lipo’s 35 “C” rating is well suited for multi-rotor applications by balancing performance and weight. This Gens ace lipo maximizes flight time with minimal voltage sag. The all black battery design with the Luminier brand will look great on any air-frame! Whether you’ve got a crawler, biped or rover, you’re going to need a battery pack to get your robot moving on its own. Lithium Polymer batteries are a great choice for robot batteries because they have great capacity-to-weight ratios, giving you lots of power for very little weight. Our 3s 11.1V 2200mAh 30C LiPo Battery is a great medium sized battery that can discharge up to 66A continously!

It is important that you pay attention to gearing; incorrect gearing along with prolonged runs using high-capacity batteries can result in excessive heat, causing it to swell and possibly catch on fire or explode. This will overheat the ESC itself and damage it and possibly overheat the motor as well. These possibilities are not strictly limited to three-cell LiPos.