A portable device that requires a high amount of power in series is generally powered by a battery pack in which two or more cells are connected in series. If a high voltage battery is used, the size of the conductors and switches can be made small. Usually we will use 42V and 12V batteries. But the 42V battery is expensive, and it produces more arc on the switch than the 12V battery. Another problem with the use of high-voltage battery packs is the possibility of failure of a certain battery in the battery pack. It's like a chain, the more batteries are connected in series, the higher the chance of this happening. As long as there is a problem with one of the batteries, its voltage will decrease. At the end of the day, a “disconnected” battery may interrupt the delivery of current. It is not easy to replace the "bad" battery, which is the difference between the battery series and parallel. Because the old and new batteries are not matched to each other. In general, the capacity of new batteries is much higher than that of older batteries.

in parallel

Parallel Use In order to get more power, two or more batteries can be connected in parallel. In addition to paralleling the batteries, another option is to use a larger battery. This approach does not apply to all situations due to the limitations of the battery that can be used. In addition, large-size batteries are not suitable for the form factor required for a dedicated battery. Most chemical batteries can be used in parallel, and lithium-ion batteries are best suited for parallel use. The battery pack consisting of four cells in parallel maintains a voltage of 1.2V while the current and run time are increased by a factor of four.

Examples of battery packs have a lower impact on high-impedance or "open-circuit" batteries in battery parallel circuits compared to battery series, but parallel battery packs reduce load capacity and reduce run time. This is like an engine that only starts three cylinders. The damage caused by the short circuit of the circuit is greater because, in the event of a short circuit, the faulty battery will quickly deplete the power of other batteries and cause a fire.

In fact, regardless of the difference between the series and parallel connection of the battery, we still have to ensure the consistency of the series and parallel connection of the battery. For different batteries to be separately charged, don't be bothered, save a little effort, cause damage to the battery, cause Security issues are big

1, in series, the current is constant, the voltage is added; in parallel, the voltage is constant, the current is added

2, although the voltage has not changed, the two 12v batteries are connected in series in order to obtain higher voltage to adapt to the electrical appliances. It is necessary to have a current of 10A above 100w, such as an inverter with a design value of 12v input, which is for switches and wires. The requirements are extremely high, so reducing the current is the main reason, it is necessary to connect two parallels, but the normal discharge current is allowed to double, if the current is only 5A when using 24v. Therefore, many places use high-voltage electrical appliances (such as electric vehicles). But some appliances are originally 12v. When their power (current) is large, the electric motor, in order to increase the working time of the battery or the current of a single battery is not enough to drive, the battery is only 12v, and the power of some electric appliances is relatively large.

The two 6V batteries are connected in series at 12V. The two 12V batteries are only 12V in parallel. The so-called parallel connection is the positive pole connected to the positive pole and the negative pole connected to the negative pole.

The two 12v batteries are connected in series in order to obtain higher voltage to adapt to the electrical appliances. The battery is only 12v, and some of the electrical appliances have relatively large power. The current of 10A is more than 100w, which is extremely demanding for switches and wires. If the current is only 5A when using 24v, the current is the main reason, so many places use high-voltage electrical appliances (such as electric vehicles). This is also the case. However, some appliances are originally 12v, for example, the design value is 12v input. Inverter, motor... When their power (current) is large, in order to increase the working time of the battery or the current of a single battery is not enough to drive, two parallel connections are required, although the voltage does not change, but the normal discharge is allowed. The current has doubled.

The difference between battery series and parallel:

Battery in series:

It means that the battery is connected end to end. That is, the positive pole of the first battery is connected to the negative pole of the second battery, and the positive pole of the second battery is connected to the negative pole of the third battery, and so on;

The series voltage is equal to the sum of the battery voltages, and the current is equal to the current flowing through each battery;

A damage in one of the battery packs will cause the entire battery pack to be unusable or the voltage to drop;

Series connection can increase the total voltage.

Battery in parallel:

It means that the first head of the battery is connected and the tail is connected. That is, the positive poles of all the batteries are connected, and the negative poles of all the batteries are connected.

The shunt voltage is equal to the individual battery voltage and the current is equal to the sum of the battery currents.

Although the battery life of the battery pack is enhanced, the damage caused by the short-circuit current is more serious;

Parallel can increase the total current.

The difference between battery parallel and series is mainly the difference in voltage and capacity. Take the voltage of 3.7V, the capacity is 3000mAh lithium battery, the same is two batteries, if it is two strings, then the battery model is: 7.4V /3000mAh, if it is two, the model will become: 3.7V/6000mAh. When connected in series, the voltage increases and the capacity does not change. When connected in parallel, the capacity is increased and the voltage is constant. But the batteries we often use are all connected in series and parallel, for example: three strings and four. I hope I can help you.

1. When the batteries are connected in parallel, the voltages are equal everywhere, that is, Ua=Ub=Uc=Uo; the current is the sum of the currents of the respective batteries, that is, Io=Ia+Ib+Ic. (See Figure 1 for a parallel circuit of the battery)

The battery is connected in parallel for the case where the voltage is constant and the current needs to be increased.

2. When the batteries are connected in series, the currents are equal everywhere, that is, Io=Ia=Ib=Ic; the voltage is the sum of the voltages of the respective batteries, that is, Uo=Ua+Ub+Uc. (See Figure 2 for the series circuit of the battery)

The battery is used in series for applications where the current is constant and the voltage needs to be increased.

Whether in series or in parallel, the output power of the battery pack increases.