Speaking of batteries, would often listen to others speaking 2S, 3S, What does that mean? Simply say, 2S refers to two cells in series battery pack, 3S refers to three cells in series battery pack, what are the benefits of in series? It is to increase the voltage, voltage and motor speed are related.
For lithium battery, 2S there is voltage of 7.4V, 3S there is voltage of 11.1 volts. Because a lithium voltage is 3.7V, and a NiMH battery is only 1.2 volts, 2.4 volts so 2S, 10S was only 12 volts.
Please note that whether it is 3.7V lithium battery or 1.2V NiMH batteries, does not mean voltage when the battery is fully charged. For lithium battery, the fully charged voltage is generally reaches 4.2V, I believe most people have the hands of mobile phone batteries Universal Charger, you can see, the general indicated above output voltages are 4.2V. And NiMH after full charge can reach about 1.5V.
In addition to voltage, then that is the capacity and discharge rate. Battery capacity to mah (mAh) as a unit, the discharge rate by C units. In short 1C for different capacity battery is not the same. 1C refers to the battery in 1C discharging can continue to work with one hour.
Example: 1500mah capacity battery continue to work one hour, then the average current is 1500ma, that is 1.5A, 1.5A that is is the battery 1C. If the above nominal 10C. Then the battery maximum discharge current is 1.5A * 10 = 15A. That is under the battery 15A is safe to use.
Another example, 1C in 1000mah capacity is 1000ma, is 1A. If the above nominal 15C. Then the maximum discharge current is 1A * 15 = 15A, the battery maximum discharge current is 15A. But the above battery is working to 15A, 10C discharge, In theory, the maximum current work using 60/10 = 6 minutes. And 1000mah work to 15A, 15C discharge, Theoretical work with this current can be used 60/15 = 4 minutes. So relatively speaking, 1500mah, 10C of the battery to be used for a longer time. So when buying batteries just consider C number is not enough. discharge battery with small C number may be more discharge than battery with C number larger. This related to the capacity.