How to Connect 12V Batteries to Make 24V (with Diagram)

When working with solar energy systems, battery configuration is crucial. Whether you're storing solar energy or setting up a backup power system, knowing how to connect batteries correctly ensures efficient power management.

In this article, we'll guide you through different setups to make 24V from multiple 12V batteries. By following the instructions below, you can understand how to connect 2, 3, 4, 6, and even 8 12v batteries to form a 24V power supply, with diagrams to assist your configuration.

Preparations of wiring 12v batteries to make 24v

Before wiring your batteries, it's essential to understand the differences between series and parallel connections, as well as follow safety instructions to minimize the risk of accidents and protect both your life and property.

Ensure that all batteries are of the same type, size, age and capacity. Mixing different types or capacities can lead to uneven charging, reduced efficiency, and shortened battery life.

For the wiring process, you'll need:

Tools and Materials
Appropriate connectors, insulated cables, a wrench for tightening terminals, and a battery monitor to test voltage after wiring.

Safety Precautions
Batteries store a large amount of energy and can be hazardous if mishandled. Work in a well-ventilated area, use insulated tools, and avoid short-circuiting the terminals. Wearing gloves and eye protection is highly recommended.

Is posible to connect 3 12v batteries to make 24v

If you have two existed 12v batteries and plan to extend the energy storage capacity, you may want to add one extra battery. However, it's never to do this, either in series with the first two batteries or in parallel with both, because:

• Connecting 3 three 12v batteries in series would give you a total of 36V instead of 24v, which is likely too high for your charge controller, unless it can also work in 36v system.
• Connecting the third 12V battery in parallel with others two 12V batteries in seires consisting a 24V system will cause a voltage mismatch will lead to sparks and damaged batteries.
• While connecting the third 12V battery in series with a parallel pair might theoretically match a 24V system, the charging process and BMS communication will be problematic. Current will not distribute evenly between batteries, leading to imbalanced performance and possible long-term damage.

The best solution is to replace the entire battery system based on your specific energy needs. Ensure that all batteries are of the same type, size, age, capacity and brand for optimal performance.

Alternatively, you could purchase two additional 12V batteries and wire them in series to create a 24V system. However, it's not recommended to connect them in parallel with your existing 24V battery bank. Instead, consider forming two separate banks with their own charge controllers, allowing them to be isolated for maintenance or other purposes.

How to connect 2 12v batteries to make 24v

Connecting two 12V batteries to form a 24V system is simple. You will need to connect the batteries in series. Here's a guide to doing so:

Step1 - Wire Two 12V Batteries

Take the positive terminal of the first 12V battery and connect it to the negative terminal of the second battery.

In this connection, the voltage from each battery is added together, making it a combined 24V output for this pair. These terminals will be used later to connect to the next part of the circuit, whether in parallel or to the load, after completing a final check.

How to connect 4 12v batteries to make 24v

To connect four 12V batteries and still achieve 24V, you can use a series-parallel configuration. This setup ensures that the system maintains 24V but increases the battery capacity (Ah).

For example, by connecting two 12V 100Ah batteries in series to get 24V 100Ah, then connecting two of these pairs in parallel, you’ll have a 24V 200Ah system.

Step1 - Group the Batteries

Divide your four batteries into two pairs.

Step2 - Connect Two 12V in Series

For the first pair, connect the positive terminal of the first battery to the negative terminal of the second battery. Repeat this for the second pair.

In each pair, the negative terminal of the first battery and the positive terminal of the second battery will now be your main terminals for the 24V output.

Step 3 - Connect the Pairs in Parallel

Now, connect the main positive terminals of each pair together and the main negative terminals together. This is the parallel connection that maintains the 24V output.

How to connect 6 12v batteries to make 24v

For larger setups like 6 or 8 batteries, the wiring process is similar to the 4-battery configuration—just repeated. For instance, with 6 batteries, you’ll create three pairs of 12V batteries connected in parallel, then connect those pairs in series to achieve a 24V output.

Each pair is wired in series first, and then the pairs are connected in parallel to maintain the desired voltage. Below, we skip the repeated steps from the 4-battery setup and provide diagrams to show how to connect 6 or 8 batteries to make 24V.

When dealing with more than one pair of batteries, it’s important to clearly distinguish between the terminals of each group to avoid confusion.

Labeling each terminal or drawing out your battery layout beforehand can help ensure you're connecting them correctly, especially when working with multiple pairs.

How to connect 8 12v batteries to make 24v

Securing and Finalizing Your 24V Battery Setup

Step 4 - Insulate and Secure Connections

After wiring, insulate the connections with electrical tape or heat shrink tubing to prevent short circuits. Ensure all connections are tight and secure.

Step 5 - Test Voltage Output

Use a voltmeter to check the voltage between the positive terminal of the first battery and the negative terminal of the last one. The reading should be around 24V, confirming a successful connection.

Step 6 - Connect to Charge Controller or Load

Lastly, connect the 24V system to the charge controller or device. Double-check the setup before powering on the system to ensure safe operation.