Short for Lithium Polymer. These are very lightweight, don't mind high discharge rates, and have very high power density. However, they are very delicate and require special circuitry to keep them from exploding while charging!. The cells are around 3.7V so 3.7V and 7.4V are the most common battery voltages you'll see. They can easily provide up to 1C of current, some can go up to 10C!
RC LiPo batteries require unique and proper care if they are going to last for any length of time more so than any other battery technology. Charging, discharging, and storage all affect the lifespan. If you get it wrong the battery is trash in as little as one mistake
If used as a receiver battery (7.4v pack) a voltage regulator might be required to step the battery voltage down to an acceptable level. Check with your radio manufacturer for details. Some servos have a maximum input voltage of 4.8V or 6.0V.
Cons: Expensive, delicate, can explode if misused!
LiFe batteries (LiFePO4 -
The cell voltage of a LIFE battery is 3.2 giving 6.4v as a receiver pack and as with Lipo a voltage regulator might be required to step the battery voltage down.
Life cells are much harder to ignite in the event of mishandling (especially during charge) although any fully charged battery will dissipate overcharge energy as heat. Therefore, failure of the battery through misuse is still possible.
The Minimum discharge voltage = 2.5V
Cycle Life at 100% DOD Typically 300
Pros: Extremely High Rate Capability, Safer Lithium Battery
Cons: Lower Capacity than standard Li-