Now FPV all use Lipo battery, and there are many pilots that they all used 3s/4s battery in the FPV racing competition.
The so-called 3s is composed of three layers lithium cells in series that shows each cell voltage is 3.7 volts, each lithium chip actual voltage is in the range of 2.75 to 4.2 volts. The capacitance marked on lithium is that the energy was getting when 4.2 volts discharge to 2.7 volts. The FPV lithium voltage must be kept at the range of 2.75 volts to 4.2 volts for use. If the battery voltage is lower than 2.75 volts, it is excessive discharge, lithium battery will expand and the chemical liquid will crystallize. The crystallization may pierce the internal structure that cause battery short circuit, even changes voltage charge into zero. The remote model airplane voltage is higher than 4.2 volts, it is overdischarge, the internal chemical reaction is too excessive and the lithium will expand, if voltage keeps charging, the RC lipo battery will expand and burn.
No matter overdischarge or overcharge, both can cause a lot of damages to remote control model airplane battery.
Because FPV battery almost use for violent flight, so must pay attention to the skills about the use and maintenance of FPV battery.
1.The charge voltage should not exceed specified limited voltage (each battery chip is 4.2 volts), 4.25 volts is the highest limitation of each charge voltage. Charge current should not be too large (like the TATTU brand charger of 1500mAh 3s battery should be set at 1.5 amperes to 2.5 amperes to charge)
2.Connect battery positive and negative electrodes correctly. If the anode and cathode of battery swap the cell's poles over will not accept a charge. Reverse charge will make battery damage, cause heating, explosion, leaking and burn.
3.Overdischarge will make battery damage. When the battery discharges, monomer battery voltage should not be less than 3.6 volts (When single cell is 3.8 volts, the plane should almost begin to descend.)
4.The battery should be kept at a cool environment. When store the battery for a long time (over 3 weeks), suggest to put in the environment that temperature keeps at 10 to 25 degree Celsius, low temperature and non-corrosive gas. Battery needs to charge and discharge once three months to keep battery activity, and ensure every chip voltage in the range of 3.7 to 3.9 volts.
5.A good battery should have a good charger. Don't use no-name charger.
6.FPV must choose the brand batteries, don't use no-brand-name batteries. Single cell voltage has big difference.
7.When fly in the hot weather, try to choose the moments that before sunrise or after sunset that the temperature is not that high. Pay attention to the heat dissipation of the battery and the electronic speed controller. If can hang the batteries and electronic speed controller outside of the plane, try to dissipate heat outside.