Electric RC off road cars can be made using one of four different types of rechargeable batteries: nickel-cadmium, nickel-metal-hydride, lithium-ion, or lithium-polymer. Each of these has benefits and drawbacks for a hobbyist.
The nickel-cadmium (NiCd) battery was the original battery in RC off road cars for hobbyists. The cadmium makes it very difficult to dispose of, and it suffers from memory effects (that is, over time, it can lose its ability to hold a charge). However, it can be pretty easy to rejuvenate if you have the correct charging system, and it is easy to detect its peak charge.
The nickel-metal-hydride (NiMH) was the next step up in battery technology for off road RC racing. It had a higher capacity than the NiCd battery and suffered from fewer memory problems, but it did require a more sensitive peak-detection method. Its environmental friendliness made it easier to dispose of, too, but it is easy to damage a NiMH battery by overcharging it or when charging it with unmatched cells.
The lithium-ion (Li-ion) was a natural choice as the technology became available; you may have heard of these batteries often being used in laptops because of their quality. They have twice the capacity of NiCd, making them last longer than NiMH, too. They use a more expensive, exotic material than their predecessors, but they can contain a controller chip that adjusts the speed of the power discharge and prevents overcharging, but it does require a specialized charger.
Lithium-polymer (Li-poly) is the latest upgrade to battery technology for those awesome buggies, truggies, and trucks. It is very lightweight and has twice the power of a Li-ion battery, meaning it has four times the power of a NiCd battery. It can be easily shaped to fit small spaces, making it perfect for an off road RC car. However, it does require a special charger, and it can be very, very dangerous if it is overcharged – exercise extreme caution in that situation. Some new charging systems address this issue, but they are even more expensive than this, the most expensive of the batteries for electric off road RC cars.
So keep an eye out for which battery would work best for you: NiCd, NiMH, Li-ion, or Li-polymer. Remember the strengths and weaknesses of each!
