Basic Introduction of Series and Parallel of Lithium Batteries

Views: 110     Author: Site Editor     Publish Time: 2022-07-01      Origin: Site Inquire

When you buy or DIY your own lithium battery pack, the most common terms you come across are series and parallel, and of course this is one of the most asked questions from the BSLBATT team. For those of you who are new to Lithium batteries, this can be very confusing, and with this article, BSLBATT, as a professional lithium battery manufacturer, we hope to help simplify this question for you!


What is series and parallel connection?


Actually, in simple terms, connecting two (or more) batteries in series or parallel is the act of connecting two (or more) batteries together, but the harness connection operations performed to achieve these two results are different. For example, if you want to connect two (or more) LiPo batteries in series, connect the positive terminal (+) of each battery to the negative terminal (-) of the next battery, and so on, until all LiPo batteries are connected. If you want to connect two (or more) lithium batteries in parallel, connect all positive terminals (+) together and connect all negative terminals (-) together, and so on, until all lithium batteries are connected.


Why do you need to connect the batteries in series or parallel?


For different lithium battery applications, we need to achieve the most perfect effect through these two connection methods, so that our lithium battery can be maximized, so what kind of effect do parallel and series connection bring to us? The main difference between series and parallel connection of batteries is the impact on the output voltage and battery system capacity.


Batteries connected in series will add their voltages together in order to run machines that require higher voltage amounts. For example, if you connect two 24V 100Ah batteries in series, you will get the combined voltage of a 48V LiPo battery. The capacity of 100 amp hours (Ah) remains the same. However, it is important to note that you must keep the voltage and capacity of the two batteries the same when connecting them in series, for example you cannot connect a 12V 20Ah and 24V 40Ah in series! Most importantly, not all lithium batteries can be connected in series, and if you need to operate in series for your energy storage application, then you need to read our instructions or talk to our product manager beforehand!


Series connection


Instead, batteries connected in parallel configuration can increase the ampere-hour capacity of the battery at the same voltage. For example, if you connect two 48V 50Ah batteries in parallel, you will get a Li-ion battery pack with a capacity of 100Ah, with the same voltage of 48V. Similarly, you can only use the same cells and capacity LiPo batteries in parallel, and you can minimize the number of parallel wires by using lower voltage, higher capacity batteries. Parallel connections are not designed to allow your batteries to power anything above their standard voltage output, but rather to increase the duration for which they can power your devices.


Parallel connection


Whether by parallel or series connection, always pay attention to the resistance and use cables with a small cross-sectional area and as short as possible. The shorter the length of the connection, the lower the resistance formed in the cable when the current flows and therefore the less energy is lost in the cable and the higher the conversion efficiency of the PV system!


Can lithium batteries only be connected in series or only in parallel?


No, series and parallel are just the most basic connections, but to meet the application scenario, we will also only series-parallel way, this way to achieve design flexibility and achieve the required voltage and current rating with standard cell size. For example, in the assembly process of Li-ion battery, BSLATT's solar lithium battery uses BYD and CATL square LiFePo4 cells, which have a voltage of 3.2V, while a complete household Li-ion battery pack usually has a voltage of 51.2V, so by using 16 series and 2 parallel, we can get a household Li-ion battery with a voltage of 51.2V and a capacity of 200Ah.


What are the benefits of connecting batteries in series?


 ● Series circuits are easy to understand and build. It is easy to understand their basic properties, ensuring easy maintenance.

 ● For large applications requiring high voltages, series-connected batteries are often the better choice.

 ● Series-connected cells provide higher system voltages, which result in lower system currents.

 ● Circuits in series do not overheat as quickly, making them useful near potentially flammable sources.

 ● Higher voltage means lower system current, so you can use thinner wiring. The voltage drop will also be smaller.

 ● In a series circuit, current must flow through all components of the circuit. This results in all components carrying the same amount of current.


What are the disadvantages of connecting batteries in series?


 ● When one point in a series circuit fails, the entire circuit fails.

 ● When the number of components in a circuit increases, the resistance of the circuit increases.

 ● Series connection increases the voltage of the battery and without a converter you will not be able to get a lower voltage from the battery pack.


What are the benefits of connecting batteries in parallel?


 ● The capacity increases the voltage remains the same, extending the run time, the more you connect in parallel, the longer you will use them

 ● If one of the batteries fails, the other batteries can still maintain power


What are the disadvantages of batteries in parallel?


 ● Longer charging time

 ● Higher current consumption and higher voltage drop

 ● Powering larger power programs and the use of generators becomes difficult

 ● Detection of defects in parallel wiring is more difficult than in series wiring.


Can BSLBATT home solar lithium batteries be connected in series or parallel?


Our standard home solar lithium batteries can be run in series or parallel, but this is specific to the battery's use scenario, and parallel is more complex than series, so if you are purchasing a BSLBATT battery for a larger application, our engineering team will design a viable solution for your specific application, in addition to adding a sink box and high voltage box throughout the system in series!


There are a few things to keep in mind when using BSLBATT's home solar lithium batteries, specific to our series.


- Our Powerwall series batteries can only be connected in parallel, and can be expanded by up to 16 identical battery packs


- Our Rack-mounted batteries can be connected in parallel or in series, up to 16 batteries in parallel and up to 400V in series


Finally, it is important to understand the different effects of parallel and series configurations on battery performance. Whether it is the increase in voltage from a series configuration or the increase in amp-hour capacity from a parallel configuration; understanding how these results vary and how to adjust the way you maintain your batteries is critical to maximizing battery life and performance.