How To Connect Batteries In Series And Parallel?

How To Connect Batteries In Series And Parallel?

While researching lithium batteries, you’ve probably seen the terms series and parallel mentioned. We are frequently asked the questions like, "what’s the difference between series and parallel”. It can be confusing if you’re new to lithium batteries or batteries in general, but hopefully, we can help simplify it.

Let’s start at the beginning - your battery bank. The battery bank is the result of connecting two or more batteries together for a single application. What does joining more than one battery together accomplish? By connecting the batteries, you either increase the voltage or amp-hour capacity and sometimes both, ultimately allowing for more power and/or energy.

The first thing you need to know is there are two primary ways to successfully connect two or more batteries: The first is called a series connection and the second is called a parallel connection.

Series Connections

Series connections involve connecting 2 or more batteries together to increase the voltage of the battery system but keeps the same amp-hour rating. Keep in mind in series connections each battery needs to have the same voltage and capacity rating, or you can end up damaging the battery. To connect batteries in series, you connect the positive terminal of one battery to the negative of another until the desired voltage is achieved. When charging batteries in series, you need to utilize a charger that matches the system voltage.

In the image below, there are two 12V batteries connected in series which turns this battery bank into a 24V system. You can also see that the bank still has a total capacity rating of 100 Ah.

Here's A Step-By-Step Guide On Wiring Batteries In Series:

• Connect the first battery's negative(-) wiring to the next battery positive(+) terminal.
• Continue wiring batteries with this technique in a straight line (your "series").
• Connect the positive(+) terminal of the first battery in the series to your application's positive(+) terminal.
• Connect the negative(-) terminal on your application to the negative(-) terminal on the last battery in the series.

What Are The Advantages of Wiring Batteries In Series?

• Circuits in the series do not quickly overheat, making them useful near a potentially flammable source, such as dry plants or tissue.
• The series circuits are simple to understand and build. It is easy to comprehend their basic nature, ensuring repairs are easy to carry out.
• In a series circuit, the current must pass through all of the circuit's components. Resulting in all components carrying the same current.

What Are The Disadvantages of Wiring Batteries In Series?

• In a series-connected battery system, you can't acquire lower voltages from the battery bank without a converter.
• When one point in a series circuit fails, the entire circuit will fail.
• When the number of components in a circuit increases, the circuit's resistance grows.

Parallel Connections

Parallel connections involve connecting 2 or more batteries together to increase the amp-hour capacity of the battery bank, but your voltage stays the same. To connect batteries in parallel, the positive terminals are connected together via a cable and the negative terminals are connected together with another cable until you reach your desired capacity.

A parallel connection is not meant to allow your batteries to power anything above its standard voltage output, but rather increase the duration for which it could power equipment. It’s important to note that when charging batteries that are connected in parallel, the increased amp-hour capacity may require a longer charge time.

In the example below, we have two 12V batteries, but you see the amp-hours increase to 200 Ah.

Here's A Step-By-Step Guide On Wiring Batteries In Parallel:

• Wire each battery's negative(-) point to the negative(-) terminal of the next.
• Proceed with the positive(+) terminals in the same way.
• Wire the last battery's positive (+) terminal to your application's positive(+) terminal.
• Proceed with the negative(-) terminals in the same way.

What Are The Advantages of Parallel Wiring?

• One of the most significant benefits of wiring batteries in parallel is: If one of the batteries fails, the other batteries can still sustain power.
• You extend your system's possible runtime while keeping the voltage constant.  

What Are The Disadvantages of Parallel Wiring?

• The main disadvantage of wiring batteries in parallel instead of series is that the voltage level will be lower, which will result in a larger current draw. The higher the current, the thicker the wires, and the higher the voltage drop. Larger power appliances and generators are more difficult to use and less efficient when operating at lower voltages.
• Parallel wiring needs a large number of wires.
• Defect detection is more difficult in parallel wiring compared to series wiring.

Batteries In Series Vs. Parallel

Which Is For me?

It depends on your needs. First, you need to clarify your electricity needs, how many electrical appliances you have, how much power and voltage the appliances are, and how much electricity you consume on an average day. Also, there is no better or worse option between series and parallel wirings. Both are important in the creation of battery systems. Parallel wirings have more challenges with charging and discharging processes. But learning how to harness the attributes of each one is necessary for a good solution. The needs of the applications you're trying to power with  (LiFePO4) Batteries will determine the strategy you implement.

How Many Batteries Can I Wire In Series?

The maximum number of batteries you can connect in series is usually determined by the battery and its manufacturer. For example. Basen 12V 100Ah model allows up to 4 lithium batteries to be connected in series to produce a 48-volt system. Always double-check with your battery maker to be sure you're not going over their recommended battery series limit.

How Many Batteries Can I Wire In Parallel?

It is largely dependent on the manufacturers. Some batteries aren't restricted in any way. With Basen 12V 100Ah, you can wire up to 4 units in Parallel. The more batteries you connect in a parallel circuit, the more capacity and runtime you'll have. Keep in mind that the more parallel batteries you have, the longer the system will take to charge.

Can Batteries Of Different Brands Be Connected In Series Or Parallel?

No, All brands of batteries are not supported to be connected with other brands of batteries because the batch of cells is not the same.

Is It Possible To Wire In Series and Parallel At The Same Time?

You can connect groups of batteries in series and parallel to build a larger battery bank with a greater voltage. For example; 4 x 12V 100Ah Lithium Iron Phosphate (LiFePO4) batteries wired in series/parallel will give you  24V 400A. Note connect in Series first and then in Parallel.

Important Points to Remember while wiring batteries in series and parallel:

• The voltage and capacity of a system wired in series will be increased.
• Wiring batteries in series will boost voltage but not capacity.
• Always use identical batteries when wiring them together.
• If you're unsure, always consult a professional.

Whether you’re seeking an increase in voltage or amp-hour capacity it’s important to understand the difference between parallel and series configurations, and the effects they have on your battery bank’s performance. Knowing the differences between these parallel versus series configurations allows you to maximize your lithium battery’s life and overall performance.

Have more questions about battery series and parallel?

Basen experts are ready to help. Get in touch and we'll find the solution you need.