Understanding Batteries In Parallel vs. Series

Series: To create a series connection, you would connect the negative terminal the to positive terminal on two separate batteries. A series connection creates a larger voltage system, and does not effect the amperage of the combined batteries. For example: while connecting two (2) 12V 100 Ah batteries in series, you are creating a 24V 100 Ah system.

Parallel: While connecting two batteries in parallel, you would connect the positive terminal to the positive terminal of the second battery, and the negative terminal to the negative terminal of the second battery. While batteries are connected in parallel, you are increasing the amperage of the system, while the voltage is unaltered. For example, while connecting two (2) 12V 100 Ah batteries in parallel, you are creating a 12V 200 Ah system.

In the example at the top of the page, the dotted lines indicate the positive and negative wire leads from the GEN2, and the solid lines indicate the wires leading back into the system (i.e. car, boat, etc.) from the battery. In the case of Isolated Batteries, simply attach the eyelets from each bank to each battery, making sure positive corresponds with positive and negative with negative. Parallel Batteries, like isolated batteries, require both positive and negative leads to be secured to the corresponding posts on the battery; the key difference is the batteries are connected to one another before leading back into the system. This increases amperage, while the voltage remains the same. Series Batteries require all leads to be plugged in just as the other two, the key difference here is the batteries are hooked to each other before leading back into the system. This increases the voltage of the system, while maintaining the same amperage.