Lipo pack`s | Lithium Polymer cell`s
Lipo pack`s | Lithium Polymer cell`s
Lipo battery `s or fully named Lithium Polymer cells come in all shapes and sizes and with even more different properties. In drag racing, there are some properties that make some lipo pack `s ideal.
We’ll look closer to the following properties:
1. Voltage;
2. Mah;
3. C-rate;
4. C Discharge rate.
Voltage of a lipo battery
Lipo battery `s come in different voltages. 3.7 volts (1s) to 37 volts (10s). In drag racing the maximum used is 11.1 volts. That means up to 3s lipo `s.
The 3 cells in a 3s lipo pack are connected in series (like Christmas lights). Each connection of a plus and a minus has a balancing cable. On the final plus and the final minus there is also a balancing cable. The balancing cables come together in the balancing connector and ensure that each individual cell during charging can be measured. Here is a diagram
The minimum and maximum voltage per cell are vital for lipo cells. During charging, individual cells are kept from overcharging. During use, individual cells are kept from deep discharge. A full lipo cell has 4.2 volt. The lower limit is a voltage of 3.1 volts.
A lipo cell below 3.1 volts, risks damage. To avoid deep discharge of the lipo cells a good esc / controller always uses a power cut-off. The power cut-off, also known as "lipo saver", can usually be adjusted. With a programming card you can set at which minimum voltage the speed controller must turn power of to secure the lipo cells. It is generally assumed that 3.1 volts per cell is the minimum.
Mah
On all lipo battery `s is a number that is followed by the abbreviation Mah (mill amperes per hour). When you use a 3000mah lipo pack you can use up to 3 amps for 1 hour from it or for 0.5 hours 6 amps at the rated voltage. The higher the number,.. the more Mah you can use and the longer you drive.
C-rate
On almost every lipo battery is a C-rate indicated. The C-rate indicates with how many amps a lipo pack can be charged. Do you have a lipo pack 3000mah/2C for example, you may charge with a maximum of 6 amps.
If there is no C-rate on a lipo pack then assume that you can load up to 1C. When charging a healthy battery at 1C nothing can go wrong. If you want faster charging you need more amps to load. This is only possible if the charger has sufficient capacity.
Discharge C-rate
Discharge C-rate refers to the amount of amps that can be given for a short time by the total lipo pack. In the interpretation of mah we have seen that you can play with consumption and longevity has a maximum. The discharge C-rate of a lipo indicates where that maximum is.
25C discharge means that a maximum of 25x the maximum mah number can be used for a duration of 5 seconds.
A 3000mah 25C discharge lipo can deliver 25x3 amps = 75 amps for a maximum of five seconds. The discharge C-rate is therefore of great importance for drag racing. A drag race takes less than 5 seconds so the maximum power to discharge is available the entire race.
When selecting a battery pack you should be taking into account all the above properties an you will have a combination of battery pack, speed controller / esc and motor that create an exactly aligned combination for maximum performance.
The Discharge C rate is crucial for good performance of the entire setup. Indeed this is the beginning of a good performing setup.
