What is the main effect of connecting multiple batteries in parallel?

Connecting multiple batteries in parallel primarily serves the purpose of equal current capacity distribution among the batteries. When batteries are connected in parallel, their total capacity (measured in amp-hours) increases while the voltage remains the same as that of a single battery. This configuration allows for a greater amount of current to be drawn from the battery bank, which is particularly beneficial in applications where high current is required, such as in substations or when powering large loads.

By connecting batteries in this manner, each battery shares the load according to its state of charge and internal resistance, which helps to ensure that no single battery is overloaded. This sharing of current can prevent overheating and prolong the overall lifespan of the batteries as they operate more efficiently. Additionally, if one battery starts to fail, the others can often compensate, leading to a more reliable power supply.

In contrast, connecting batteries in series would increase the overall voltage of the system, while creating additional risk if one battery fails, potentially affecting the others. The other options, such as reduction in individual battery life or overall power supply, do not reflect the main benefit of a parallel connection, as proper management and maintenance can mitigate these concerns.