Batteries in Series and Parallel
Batteries in Series and Parallel
The battery is a device that consists of one or more electrochemical cells with external connections for powering electrical appliances. When there are multiple batteries in a given circuit, they are either wired in parallel or series connection. Understanding the difference between series and the parallel connections is crucial as they determine how batteries perform in different applications. In this article, let us look at batteries’ series and parallel connection and when each method is appropriate.
Batteries in Series and Parallel
Batteries can either be connected in series, parallel or a combination of both. In a series circuit, electrons travel in one path and in the parallel circuit, they travel through many branches. The following sections will closely examine the series battery configuration and the parallel battery configuration.
Connecting Batteries in Series
A set of batteries is said to be connected in series when the positive terminal of one cell is connected to the negative terminal of the succeeding cell.
The overall emf of the battery is the algebraic sum of all individual cells connected in series.
If E is the overall emf of the battery combined by n number of cells, then
E = E1 + E2 + E3 + E4 + ………..+ En
Similarly, if r1, r2, r3 are the internal resistances of individual cells, then the internal resistance of the battery will be equal to the sum of the internal resistance of the individual cells.
r = r1 + r2 + r3 + ……..+ rn.
Advantages
Wiring batteries in series provides a higher system voltage resulting in a lower system current. Low current indicates that you can use thinner wiring and suffer less voltage drop in the system.
Disadvantages
In a series-connected battery system, a converter is needed to achieve low voltages.
Connecting Batteries in Parallel
A set of batteries are said to be connected in parallel when the positive terminals are connected together, and similarly, the negative terminals of these cells are connected. These combinations are referred to as parallel batteries.
If the emf of each cell is identical, then the emf of the battery combined by n numbers of cells connected in parallel is equal to the emf of each cell. The resultant internal resistance of the combination is,
Internal Resistance of Parallel Combination
The current delivered by the battery is the sum of currents delivered by individual cells.
Advantages
One of the prominent advantages of batteries connected in parallel is that if one of the batteries in the system fails to operate, the remaining batteries can still provide power.
Disadvantages
Connecting batteries in parallel results in a higher current draw. This indicates thicker cables and more voltage drop.
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