How to Connect LiFePO4 Solar Batteries in Series and Parallel?

Introduction

The most frequent phrases you will encounter while purchasing or building you own LiFePO4 solar battery packs are series and parallel, and this is undoubtedly one of the most frequently asked questions of the ROYCE team. This can be really complicated for those of your who are unfamiliar with LiFePO4 solar batteries. With this post, ROYCE, a reputable manufacturer of LiFePO4 battery Packs, hopes to help make this question easier for you !

Series and Parallel Connection: What Is It?

In actuality, joining two or more batteries together in series or parallel is simply connection them together, but the harness connection activities needed to accomplish these two outcomes are different. If you wish to connect two or more LiFePO4 batteries in series, for instance, connect each battery's positive terminal(+) to the subsequent battery's negative terminal (-), and so on, until all of the LiPo batteries are linked. Connect all positive terminals (+) and all negative terminals (-) together, and so on, until all lithium batteries are connected, if you choose to connect two or more in parallel.

Why Is It Necessary to Connect the Batteries Parallel or Series?

What type of effects do parallel and series connections offer us? For various LiFePO4 solar battery applications, we need to get the best possible outcome using these two connection methods in order to optimize our solar LiFePO4 battery. The influence on the output voltage and battery system capacity is the primary distinction between connecting LiFePO4 solar batteries in series and parallel.

Machines requiring higher voltage levels can be powered by a series connection of LiFePO4 solar batteries, which adds their voltages together. For instance, the combined voltage of two 24V 100Ah batteries connected in series will equal a 48V battery. There is no change in the capacity of 100 amp hours (Ah). It's crucial to remember that when connecting two batteries in series, their voltage and capacity must remain the same. For instance, you cannot connect a 12V 100Ah and a 24V 200Ah battery in series! Above all, keep in mind that not all LiFePO4 solar batteries are designed to work in series. If your energy storage application requires you to operate in series, make sure you read our instructions or contact our product manager beforehand!

The following is how LiFePO4 solar batteries are connected in series

Typically, a series connection is made between any number of LiFePO4 solar batteries. To ensure that the same current passes through all batteries, the positive and negative poles of two batteries are connected. The overall voltage that results is equal to the sum of the component voltages.

As an illustration, two batteries with a capacity of 200 Ah and a voltage of 24 V each connected in series will produce an output voltage of 48 V.

Alternatively, a bank of LiFePO4 solar batteries connected in parallel can boost the battery's ampere-hour capacity while maintaining the same voltage. For instance, if two 48V 100Ah solar batteries are connected in parallel, the result is a 200Ah LiFePO4 solar battery with a 48V voltage. Similar to this, you can reduce the number of parallel cables by utilizing lower voltage, higher capacity LiFePO4 solar batteries; however, you can only use the same batteries and capacity in parallel. The purpose of parallel connections is to extend the amount of time that your batteries can power your devices, not to enable them to power anything above their standard voltage output.

This is the method for connecting LiFePO4 solar batteries in parallel.

Positive terminals are connected to other positive terminals and negative terminals are connected to other negative terminals when solar LiFePO4 batteries are connected in parallel. The overall voltage then equals the voltage of the individual LiFePO4 solar batteries, and the charge capacity (Ah) of the individual LiFePO4 solar batteries adds up. Generally speaking, only LiFePO4 solar batteries with identical voltages, energy densities, and states of charge should be linked in parallel. Additionally, wire lengths and cross-sections should match exactly.

Example: An output voltage of 48V and a total capacity of 200Ah are obtained by connecting two batteries, each having a 100 Ah and 48V capacity, in parallel.

What are the advantages of serial connection of solar LiFePO4 batteries?

First of all, building and comprehending series circuits is simple. Series circuits have straightforward fundamental characteristics that make maintenance and repair simple. Because of its simplicity, it is also simple to compute the expected voltage and current and predict how the circuit would behave.

Second, series-connected batteries are frequently a preferable option for applications that call for high voltages, such as a three-phase solar system installed at home or commercial and industrial energy storage. The battery pack's overall voltage rises when several batteries are connected in series, supplying the necessary voltage for the application. This can simplify the system's architecture and need fewer batteries overall.

Thirdly, lower system currents are produced by greater system voltages offered by LiFePO4 solar batteries coupled in series. This occurs as a result of the series circuit's distribution of voltage, which lowers the current passing through each battery. A system that has lower system currents loses less power as a result of resistance, making it more efficient.

Fourthly, series circuits are beneficial close to potentially combustible sources since they do not overheat as quickly. Each battery in the series circuit experiences a lesser current than if the same voltage were applied across a single battery because the voltage is spread among the batteries. As a result, there is less chance of overheating and less heat produced.

Fifth, thinner wiring can be employed since higher voltage results in lower system current. Additionally, there will be less voltage drop, bringing the voltage at the load closer to the battery's nominal value. This can lower the requirement for costly wiring and increase system efficiency.

Lastly, current needs to pass through each part of the circuit in a series circuit. As a result, the same amount of current flows through each component. By ensuring that every battery in the series circuit receives the same amount of current, this helps to maintain a balanced charge across the batteries and enhances the battery pack's overall performance.

What Drawbacks Do Series Battery Connections Have?

First of all, a series circuit fails as a whole when one point fails. This is so that current can only pass through a series circuit when there is a break in the single path that allows current to flow through the circuit. If one LiFePO4 solar battery in a pack of tiny solar power storage systems fails, the entire pack might not function. By keeping an eye on the batteries and isolating a failing battery before it affects the rest of the pack, a battery management system (BMS) can help to mitigate this.

Second, a circuit's resistance rises as the number of components in the circuit does. The overall resistance of a series circuit is equal to the sum of the resistances of its individual components. The total resistance of the circuit rises with the number of components added, which can lower the circuit's efficiency and increase power loss from resistance. This can be lessened by utilizing parts with reduced resistance or by lowering the circuit's total resistance by utilizing a parallel circuit.

Thirdly, a series connection raises the battery's voltage; obtaining a lower voltage from the battery pack might not be feasible without a converter. For instance, 48V will be the voltage that results from connecting two 24V battery packs in series. Each battery pack has its own voltage. Without a converter, connecting a 24V device to the battery pack will result in an excessively high voltage that could harm the equipment. This can be avoided by lowering the voltage to the necessary amount using a voltage regulator or converter.

What Advantages Do Parallel Battery Connections Offer?

The ability of LiFePO4 solar battery banks to be connected in parallel to increase capacity while maintaining the same voltage is one of their key benefits. This extends the battery pack's run duration; the longer the battery pack can be utilized, the more batteries that are connected in parallel. For instance, connecting two LiFePO4 batteries with a 100Ah capacity in parallel will result in a 200Ah capacity, doubling the battery pack's runtime. This is very helpful for programs that need more time to run.

The ability of the other LiFePO4 solar batteries to continue to provide power in the event of a failure is another benefit of a parallel connection. Because each battery in a parallel circuit has a separate path for current flow, the circuit can still be powered by the other batteries in the event of a failure. This is so that the remaining batteries can continue to operate at the same voltage and capacity without being impacted by the failing battery. This is crucial for applications that demand a high degree of dependability.

What Drawbacks Come with Linking LiFePO4 Solar Batteries in Parallel?

The LiFePO4 solar battery bank's overall capacity is increased when batteries are connected in parallel, but this also lengthens the charging time. If more batteries are connected in parallel, the charging process could get trickier to control and take longer.


The current is divided across solar LiFePO4 batteries when they are linked in parallel, which may result in higher voltage drop and current consumption. Issues may arise, including decreased effectiveness and battery overheating.

When employing generators or powering larger power programs, connecting solar LiFePO4 batteries in parallel can be problematic since the generators may not be able to withstand the high currents generated by the parallel batteries.


Defects in the wiring or individual batteries may be harder to find when lithium solar batteries are connected in parallel. This may make it more difficult to find and address issues, which may lead to decreased effectiveness or even safety risks.

Is it feasible to connect LiFePO4 batteries in parallel as well as series?

It is possible to link LiFePO4 batteries in both parallel and series; this type of connection is known as series-parallel. The advantages of both series and parallel connections can be combined with this kind of connection.

A series-parallel connection consists of connecting several groups of batteries in series after grouping two or more in parallel. This keeps your system dependable and secure while enabling you to raise the battery pack's capacity and voltage.

For instance, you may connect two of your four 50Ah LiFePO4 batteries with a nominal voltage of 24V in parallel to make a 100Ah, 24V battery pack. Afterwards, using the remaining two batteries, you could make a second 100Ah, 24V battery pack. By connecting the two packs in series, you could then make a 100Ah, 48V battery pack.

Series and Parallel Connections for LiFePO4 Solar Batteries

Combining a series and parallel connection allows for more versatility when utilizing standard batteries to generate a certain voltage and power. The series connection provides the greater working voltage that the battery storage system needs, and the parallel connection provides the whole capacity that is required.

Example: In a series-parallel connection, four batteries of 24 volts and 50 Ah each produce 48 volts and 100 Ah.

Recommended Practices for Connecting LiFePO4 Solar Batteries in Series and Parallel

When connecting LiFePO4 batteries in series or parallel, best practices must be followed to guarantee their safe and effective use. Among these methods are:


● Make use of same sized and voltaged batteries.
● Make use of identical manufacturer and batch batteries.
● To balance and monitor the battery pack's charge and discharge, use a battery management system (BMS).
● To safeguard the battery pack against overcurrent or overvoltage situations, utilize a fuse or circuit breaker.
● Reduce heat generation and resistance by using high-quality wiring and connectors.
● Steer clear of overcharging or overdischarging the battery pack as this may shorten its lifespan or result in damage.

Is it possible to connect ROYCE Home solar LiFePO4 batteries in parallel or series?

Our engineering team will design a workable solution for your particular application, in addition to adding a sink box and high voltage box throughout the system in series, if you are purchasing a ROYCE battery for a larger application. Our standard home LiFePO4 solar batteries can be run in series or parallel, but this depends on the battery's use scenario. Additionally, series is more complex than parallel!

When using ROYCE's home solar LiFePO4 batteries, there are a few considerations that are unique to our series.


- Our Powerwall batteries can be increased by up to 16 pcs identical battery packs, however they can only be linked in parallel.

- Up to 16 pcs batteries can be linked in parallel with our rack-mounted batteries.


Lastly, it's critical to comprehend how battery performance is affected differently by parallel and series topologies. Optimizing battery life and performance requires knowing how these outcomes differ and knowing how to modify your battery maintenance practices. This applies to both the increase in voltage from a series arrangement and the increase in amp-hour capacity from a parallel configuration.