Types and Characteristics of RC batteries
1・Nickel-Cadmium battery (Ni-Cd battery)
Ni-Cd batteries are popular rechargeable batteries and a variety of capacities are available. Nowadays, a large capacity such as 5000mAh is common. For RC purpose, we use a battery cell with nominal voltage of 1.2V and make a battery pack with 4 to 6 of these cells. 4 cells packs are 4.8V and these can be used for powering transmitters or receivers. 5 cells packs are 6.0V and these can be used as a receiver or transmitter pack just like with 4 cells packs. 6 cells packs are 7.2V and these can be used for powering motors. Receiver packs are used for supplying the power to receiver and servos. These are necessary for gas/nitro engine RC because such RC vehicles don’t have any power source for the receiver. Characteristic of Ni-Cd batteries, they have low internal resistance and they can deliver large currents. That is why Ni-Cd batteries are still kept being used in RC. These batteries contain cadmium which is a toxic substance, this is why these batteries are getting used less frequency.
2・Nickel-Hydrogen/Nickel-Metal Hydride battery (NiMH battery)
NiMH batteries have been introduced as an alternative to Nickel-Cadmium batteries. This battery is also rechargeable, but it contains no toxic cadmium. It is about the same in size and voltage as well as discharge characteristics as Ni-Cd batteries so there is no problem to use them in RC purposes. However, this battery must be cared for when stored. NiMH have high discharge rates and easily get self-discharged. They are impossible to charge once the voltage drops below minimum voltage. To detect delta peak while charging is delicate - which can lead to overcharging and destroying these batteries.
3・Lithium-Ion battery(Li-ion battery)
These are popular rechargeable batteries that are small but have a large capacity. Higher voltage, 3.7V per cell makes this battery ideal to use for devices such as mobiles and digital cameras who require higher power. These batteries contain Lithium in the electrolyte which results in a higher voltage and less self-discharged. On the other hand, the internal electrolyte can be activated in case it is overcharged or over-discharged. As a result, they can get hot and start burning or explode resulting in possible serious damage to yourself and your surroundings. Although these batteries have protection circuits to prevent over charging or over discharging, a compatible Li-ion charger is required.
4・Lithium-Polymer battery (Li-Po battery)
This is one kind of the rechargeable Lithium batteries and is rechargeable. The electrolyte is composed with macromolecular polymer. Basically, this battery is same as Lithium-ion battery so compatible charger is required and we have to take care not to overcharge or over-discharge. Mostly, these batteries are used for RC Hobby purposes and a variety of capacities, size and cell configuration are available on the market. This kind of Lithium battery is also dangerous, and we have to take care how to store them to prevent fires.
5・Lithium-Ferrite battery (LiFe battery) or Lithium-Ion-Phosphate(LiFePO4)
This battery is another Lithium battery. Different from other Lithium batteries, the voltage per cell is 3.3V. Although the batteries are smaller and have higher capacity compared to other Lithium batteries, these batteries have low discharge rates so are not suited for RC electronic devices such as motors. This battery is one kind of Lithium batteries that are less dangerous, but we must still take care not to overcharging and over-discharging just like other Lithium batteries. These batteries are hard to ignite thanks to its chemistry but still need appropriate charging and storage using a compatible charger as well.