How to Connect 4 12V Batteries to Make 24V

When setting up a 24V battery system using 12V batteries, there are two primary methods:

  • Connecting the batteries in series first
  • Connecting the batteries in parallel first

In this article, I will discuss both methods and guide you through connecting 4 12V batteries to create a 24V system.

Key Takeaways
  • Series First Method: Connect two batteries in series, and then connect these sets in parallel.
  • Parallel First Method (Preferred): Connect two sets of batteries in parallel and then connect these sets in series.
  • Always charge your battery to 100% before connecting them together.

Connecting Series First – Fastest Method


  • Simplicity: Connecting batteries in series is a simple process involving fewer connections than parallel connections.


  • Imbalanced Discharge: In series connections, any imbalances in the battery state of charge can lead to uneven discharging, potentially affecting the overall battery lifespan.

To connect four 12V, 100Ah batteries to make 24 Volts, we first connect two batteries in series.

If we connect two batteries in series, we make two sets of 24V, 100Ah batteries.

Series connection first to make two sets of 24v 100ah

Now, we need to connect these two sets of 24V 100Ah batteries in parallel to become 24V 200Ah.

Series connection first, then parallel to make 24v 200ah

Connecting Parallel First – Preferred Method


  • Balanced Discharge: Parallel connections help to distribute the load evenly across the batteries, leading to more balanced discharging and potentially longer battery life.


  • Complexity: Connecting batteries in parallel first involves one more connection than series, making the process more complex and time-consuming.

In this system, we will connect the batteries in parallel first. We can do this by creating two sets of batteries and connecting the positives and negatives.

Parallel first to make 12v 200ah batteries

We will then series connect these two battery sets to get 24V, 200Ah.

Parallel first, then series to make 200ah 24v
 If you connect batteries in series, ensure they are at the same state of charge! Always use safety goggles and insulated tools when working with batteries! 



Both methods of connecting 12V batteries to create a 24V system have pros and cons. Method 2 is preferred.

Don’t forget to use the proper fuse and wires for your battery.

9 thoughts on “How to Connect 4 12V Batteries to Make 24V”

  1. I like the parallel series connection would be great if you could post a diagram connected to the charge controller, then to the inverter


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