Thursday, 21 May 2015
Guide of RC Battery: Lithium-Polymer Batteries Basics Part
With many advantages such as low weight, high energy density, and ever greater discharge rates, Lithium-Polymer (LiPo) batteries have been wodely used on RC. The emergence and continual improvement of these batteries has provided an excellent performance boost for RC cars, boats, airplanes, and helicopters, while also paving the way for new vehicles such as multi-rotors. All of this electric goodness does not come without a cost. If not handled and utilized properly, LiPo batteries can quickly become damaged or even catch on fire. Today, I would like to share some basic things you should know about making the most of LiPo batteries. I will also provide techniques to mitigate the risks that these batteries pose.
When talking about a LiPo, it's neccessery to know the primary characteristics to understand the battery’s voltage and capacity. This is typically noted in a shorthand such as “4S-2200”. In this case, “4S” denotes that the battery has four cells in series. The nominal voltage of each cell is 3.7 volts (4.2v fully-charged), so the total pack voltage is:
4 cells x 3.7v = 14.8v.
The "2200" means the capacity of the battery in milliamp-hours (mAh). A fully charged 2200mAh pack can provide a current of 2200 milliamps (2.2 amps) per hour before it is fully discharged. This capacity value is completely independent of how many cells are in series. In simple terms, the capacity value allows you to estimate how long a battery will provide useful power in a given application. In practical terms for RC use, the capacity rating is typically only helpful for rough comparisons of different batteries. i.e. a 2S-5000 battery will provide about double the run time of a 2S-2500 lipo in the same RC car.
It's quite common when it was 10 years ago, while is now rare to find a RC LiPo battery that uses cells in parallel. Let’s look at an example in case you happen across one. A 4S2P-2200 battery would consist of two 4S-1100 batteries wired in parallel to provide a total 2200mAh capacity. All other things being equal, you would care for and use this battery the same as you would the previous 4S-2200 example (which is really a 4S1P-2200, but we ignore the 1P). There may be a difference in physical size, but a 4S-2200 and a 4S2P-2200 are functionally equivalent. The differences will really only matter to the guy at the factory who has to assemble the battery.
Custom battery pack,Protection circuit modules Lithium Polymer Battery