LiFePO4 Batteries: In Series vs. in Parallel, Which Is Better?
Aug 29, 2023
With an outstanding performance, lithium-ion batteries have exceptional performance. It requires higher voltage if you have a boat, a solar system, or a motorhome. Your option is to connect your batteries in parallel or series. However, which one is better?
It is vital to have an understanding of how batteries can perform. Additionally, both methods do increase the total available energy in watt-hours. However, these goals are reached in different ways and with different results.
As you continue reading, you will discover all the details about connecting batteries in series and parallel. This will help you determine which is better for you.
Types of Battery Connections
You will encounter three types of battery connections.
- Series Connection
- Parallel Connection
- Series-Parallel Connection
Series Connection of LiFePO4 Batteries
Series connection of lithium-ion batteries refers to a sequential relationship of multiple cells to increase the voltage. This process does not increase the ampere capacity. Please note that the batteries should have the same voltage and rated capacity before being connected in series.
In this sequence, the positive terminal of one cell is connected to the negative terminal of the next one. You can join as many as you desire to achieve the desired voltage.
There are several advantages in regards to connecting batteries in series, including the following:
- Better application for devices with higher voltage or larger power systems.
- It forms a lower system current. Less current means you can use thinner wiring and suffer less voltage drop in the system.
- Less voltage drop
- Thinner wiring
- More efficient energy storage. Each cell shares the load equally. The charge and discharge rate is the same.
- Ideal for electric vehicles and solar power energy systems.
The series connection has some drawbacks.
- Risk of overcharging. You need to make sure the V and capacity are the same. Otherwise, they´ll discharge at different rates and imbalance the pack´s voltage if they differ.
- Decrease capacity
- All your applications have to work at their highest voltage. If one of your devices needs to be unplugged into a 12V, you cannot connect it to these batteries. Because the voltage is 24V, so you will need a converter.
How to Connect Batteries in Series
- The negative of one battery should be coupled with the positive of the following battery.
- Continue connecting them until all the batteries are in a line (series).
- Now wire from the positive terminal of your first battery in your series to the positive terminal of your device.
- Now, wire the negative terminal of your last battery in your series to the negative terminal of the same device.
Note: Measure the voltage output of the positive terminal of the first battery and the negative terminal of the last battery. For instance, if you wire two batteries, you will have from 12V to 24V. However, three might have a voltage output of 36V.
Parallel Connection of LiFePO4 Batteries
Wiring batteries in parallel, you need to connect all the positive and negative terminals together. This will make your batteries be placed in “parallel.”
Even though this is not the main distinction between series and parallel, they differ in how series increases the voltage output. Parallel connection increases the battery capacity.
- Increase capacity and maintain voltage. As a result, you can run your device longer.
- If one battery malfunctions, it won´t affect the rest and will still have power.
- The run time increases depending on the amount of batteries you connect. If you have two, then it is double. If there are three, it is triple, and so on.
- It can take longer to charge.
- With lower voltage, you have a higher current draw, making it not possible to charge large devices or will be less efficient.
How to Connect Batteries in Parallel
- Connect first the negative terminal of each battery.
- Do the same procedure with the positive.
- Connect the positive terminal of the last battery to your device.
- Connect the negative terminal of the last battery to the same device.
What’s The Difference Between Wiring Batteries in Series Vs. Parallel?
The main difference between each one is the voltage output and the system of the battery´s capacity.
If you connect in series, you will have voltages added together. If you connect in parallel, you will have capacity added together. They share one characteristic: the total available energy is the same.
For instance, if two batteries are wired in series, they have 24V and 100Ah capacity. If you wire two batteries in parallel, you will have 12V and 200Ah. As a result, you will have any of these options with an energy of 2400 watt hours.
Note: The batteries need to have the same voltage and capacity rating for both types of connection.
Which Connection is Better for Me?
Both connections work. Neither connection is “better” than the other. Connecting your batteries in series or parallel depends on the devices you need to power. For instance, connecting in parallel for devices such as RVs or boats is recommended. This is because it has simpler wiring and a common voltage. However, series is the safest option for larger devices that need 3000 watts of power.
You need to make sure you understand the wiring configuration. Once you do, you can determine which is the best option for you.
All in All
Connecting LiFePO4 batteries in series or parallel increases battery performance and is used in different applications.
Yet, it is vital to know how these connections are built to ensure optimal performance and safety. Balance, proper wiring, and uniformity are essential for parallel connections. Uniformity, charging, and safety have to be considered in series connections.
We highly recommend not to connect old with new batteries but to connect batteries with consistent performance.
For more information about LiFePO4 batteries, head to our blog section.