Battery packs achieve the desired operating voltage by connecting several cells in series; each cell adds its voltage to the total terminal voltage. Parallel connection attains higher capacity for increased current handling; each cell adds to the ampere/hour (Ah) count.
Serial Connection
Portable equipment needing higher voltages use battery packs with two or more cells connected in series. Figure 1 shows a battery pack with four 3.7v cells in series to produce 7.4V . In comparison, a six-cell lead acid string with 2V/cell will generate 22.2V, and four Lipo battery with 3.7V/cell will give 14.8V.
Parallel Connection
If higher currents are needed and larger cells are not available or do not fit the design constraint, one or more cells can be connected in parallel. Most battery chemistries allow parallel configurations with little side effect. Figure 4 illustrates four cells connected in parallel. The voltage of the illustrated pack remains at 1.20V, but the current handling and runtime are increased fourfold.
Following is some examples for Lipo battery in Series and Parellel, you will know clearly about series and parellel.
Connecting a pair of 2s, 7.4v, 2200mah, 20c LiPo's in Series:
This will increase the VOLTAGE x 2 but the mAh and Discharge Rate (C rating) will remain the same for a result of 14.8v, 2200mah, 20c. Exactly the same as a single 4s, 14.8v, 2200mAh 20c battery.
Connecting a pair of 2s, 7.4v, 2200mAh 10c LiPo's in Parallel:
This will increase the MAH and C RATING x 2 but the voltage will remain the same for a result of 7.4v, 4400mAh, 20c. Exactly the same as a single 2s, 7.4v, 4400mAh 20c battery.
batteries in series = add the voltages/# cells together, capacity (mAh) of both must be the same and it doesn't change.
batteries in parallel = add the capacities together, voltage/# cells must be the same and doesn't change.
3S 2200mAh in series with 3S 2200mAh = 6S 2200mAh
3S 2200mAh in parallel with 3S 2200mAh = 3S 4400mAh
For example, a 10C 3S 1500 mah and a 25C 2200mah 3s lipo battery pack in parallel should only be expected to put out 35 amps, or 10C of a 3500 mah parallel setup.
When you connect 2 LiPo's in parallel yourself, you make the tradeoff of Weight and convenience. Your pair of 2s, 7.4v, 2200mah, 10c batteries will double both the mah (to 4400mAh) and the Discharge rate (to 20c) and function the same as a 2s, 7.4v, 2200mah, 20C battery. They will, however, be heavier overall than a single 2s, 7.4v, 4400mah, 20c LiPo. The 2 batteries having 2 power wires and 2 balance/charging wires as well as the wiring you do to connect them also add to your overall weight. You also have to make connectors for it all (or buy them) and plug, unplug and charge the batteries individually instead of dealing with just one.
Serial Connection
Portable equipment needing higher voltages use battery packs with two or more cells connected in series. Figure 1 shows a battery pack with four 3.7v cells in series to produce 7.4V . In comparison, a six-cell lead acid string with 2V/cell will generate 22.2V, and four Lipo battery with 3.7V/cell will give 14.8V.
Parallel Connection
If higher currents are needed and larger cells are not available or do not fit the design constraint, one or more cells can be connected in parallel. Most battery chemistries allow parallel configurations with little side effect. Figure 4 illustrates four cells connected in parallel. The voltage of the illustrated pack remains at 1.20V, but the current handling and runtime are increased fourfold.
Following is some examples for Lipo battery in Series and Parellel, you will know clearly about series and parellel.
Connecting a pair of 2s, 7.4v, 2200mah, 20c LiPo's in Series:
This will increase the VOLTAGE x 2 but the mAh and Discharge Rate (C rating) will remain the same for a result of 14.8v, 2200mah, 20c. Exactly the same as a single 4s, 14.8v, 2200mAh 20c battery.
Connecting a pair of 2s, 7.4v, 2200mAh 10c LiPo's in Parallel:
This will increase the MAH and C RATING x 2 but the voltage will remain the same for a result of 7.4v, 4400mAh, 20c. Exactly the same as a single 2s, 7.4v, 4400mAh 20c battery.
batteries in series = add the voltages/# cells together, capacity (mAh) of both must be the same and it doesn't change.
batteries in parallel = add the capacities together, voltage/# cells must be the same and doesn't change.
3S 2200mAh in series with 3S 2200mAh = 6S 2200mAh
3S 2200mAh in parallel with 3S 2200mAh = 3S 4400mAh
For example, a 10C 3S 1500 mah and a 25C 2200mah 3s lipo battery pack in parallel should only be expected to put out 35 amps, or 10C of a 3500 mah parallel setup.
When you connect 2 LiPo's in parallel yourself, you make the tradeoff of Weight and convenience. Your pair of 2s, 7.4v, 2200mah, 10c batteries will double both the mah (to 4400mAh) and the Discharge rate (to 20c) and function the same as a 2s, 7.4v, 2200mah, 20C battery. They will, however, be heavier overall than a single 2s, 7.4v, 4400mah, 20c LiPo. The 2 batteries having 2 power wires and 2 balance/charging wires as well as the wiring you do to connect them also add to your overall weight. You also have to make connectors for it all (or buy them) and plug, unplug and charge the batteries individually instead of dealing with just one.
