Differences in series and parallel & Which Is Better? 2022-07-13

When a battery voltage/capacity no longer matches the energy requirements of your application setup such as RV Boat or Solar, wiring in series/parallel may solve the problem.

Both series and parallel methods ultimately increase the total power energy (Wh), but the results are different. Let's learn more about series and parallel.

How to Wire Batteries in Series?

First, it's necessary to make sure that the batteries that need to be connected in series have the same voltage and capacity.

1) Connect the positive terminal of the battery to the negative of another one and so on until all batteries are connected.

2) Connect a cable to the negative terminal of the first battery to the positive terminal in your string to your application device, then another cable to the positive terminal of the last battery in your string to your application.


After connecting the battery packs in series, the total voltage increases and the capacity keep the same. For example, two 12V 100Ah battery packs are connected in series, resulting in a 24V battery pack, but the capacity is still 100Ah.


In general, a larger device requires higher voltages, such as home solar energy storage, mostly a 48V system. Higher voltage also results in less current, you can use thinner wiring. However, it is necessary to select another suitable charger according to the change of the total voltage after the series connection. For example, a 24V battery pack is no longer suitable for the original 12V charger and will require a 24V charger for charging.


Many LiFePO4 batteries do not support series connections, it will damage the battery. The series connection has certain requirements for the selection of the MOS of the protection board,and the max withstand voltage value of the MOS selection is determined according to the max series number after the series connection. The batteries provided by OSN can do it. You only need to explain your series requirements with your sales, and OSN will provide the most suitable solution for your needs.


How to Wire Batteries in Parallel?

Connecting in parallel has high requirements on the consistency of the battery pack. It includes the consistency of voltage, internal resistance, and capacity.

1) Connect the negative of each battery to the negative of the battery next to it, positive do the same.

2) Connect the positive terminal of the last battery to the positive terminal on the setup. Do the same for the negative terminal.


What the parallel connection ultimately brings is an increase in capacity, while the voltage remains the same. For example, two 12V100Ah are connected in parallel, the voltage same, but the capacity is doubled to 200Ah. The advantage is that the battery can last longer hours.  Paralleling increases capacity but needs more charging time. At the same time, the voltage is the same, the lower voltage also means higher current, and has to use thicker cables.

In the parallel method, if there is a problem with one of the batteries, it will not affect the use of the other batteries, and the working batteries will continue to power your application.


Connecting in series, capacity same but voltage increases, while voltage same but capacity increases when wiring in parallel. This is the biggest difference between series and parallel. Neither connection method is "better" and safer than the other. There are a lot of things to pay attention to, such as the consistency of the battery, the consistency of the protection board, the MOSFET withstand voltage of the BMS and the selection of cables. Otherwise, it will affect the performance, cycle life, and usage of the final battery pack.


Therefore, the best way is to let OSN directly provide the final suitable system for your application. 12V/24V/36V/48V/72V and so on are available. Applications for boats, RVs, golf carts, energy storage, etc. So you won't need to worry about series-parallel technology problems. Any needs, please contact or for help and inquiry.

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