Solar power is becoming more and more popular as a clean, renewable, and environmental friendly energy. For continuous consumption, we store them in batteries. In a solar panel system, the battery is a core component to store power generated by the sun during the daytime and for use to supply your application during the evening when there is no sunlight. As we all know, each battery has its voltage range and capacity according to its chemical materials, size, etc. When we need to power appliances that need larger voltage or larger capacity, what will you do? Wiring the batteries in series or parallel? What is the difference between batteries in series or in parallel? In this article, we will share the info in detail.
How do you connect batteries in series?
Batteries in series will increase the amount of voltage for these batteries. For example, when you wire three 12v 100Ah batteries in series, you will get 36v 100Ah, the total amount of power is 3600VAH, 3.6KW.
Wire the batteries in series, step by step:
- Connect the positive terminal of the first battery to the negative terminal of the second battery;
- Connect the positive terminal of the second battery to the third battery, and connect more batteries in this way;
- Wire the negative terminal of the first battery to the negative terminal of your load, and wire the positive terminal of the last battery to the positive terminal of your load.
Advantages of batteries in series
Batteries in series can get the voltage you need to power your specific appliance when one battery can not meet your requirements. And batteries in series get a stable current that is the same as each battery, thus beneficial for appliances that require such a stable power supply.
Disadvantages of batteries in series
Batteries in series will get higher voltage, which also means it requires more careful monitoring of the batteries. In these series, current is limited by the weakest battery, and one battery failure will impact the entire series string.
Wire batteries with different voltages in series, is it right?
While you connect batteries in different voltages together, you will get a higher voltage, but there are several issues that need to be considered.
- Imbalanced charging and discharging
Batteries with different voltages will charge and discharge at different rate. The battery with lower voltage will drain faster than the batteries with higher voltage during discharging, when it is fully discharged, it will act as a load, which will affect the total performance of the batteries string.
- Reduced Capacity
The overall capacity of the batteries in series will be limited by the battery with the lowest voltage.
- Reduced battery lifespan
The inconsistent charge and discharge can lead to severe degradation of the batteries. In the long run, it can reduce the lifespan of the battery strings in series.
- Safety Issues Concerns
The imbalanced voltage of the batteries in series may lead to overheating, fire or explosion hazards in extreme cases.
In conclusion, connecting batteries with different voltages is not recommended. So before you make a decision to connect batteries in series, please check carefully about their voltage to ensure they have the similar voltage rate.
How many batteries are suitable for wiring in series?
Considering the batteries quantities to be connected in series depends on several factors.
- Voltage Requirements
Batteries in series increase voltage. The quantities of batteries connected in series depends on your desired voltage for your application. If your application voltage needs is 51.2V, and you have 12.8V 100Ah batteries, then you can connect 4 units of them in series.
- Battery specification
Before connecting batteries in series, make sure that you already read the user manual from the manufacturers carefully, and you totally understand the concerns and limits that mentioned in it.
- BMS Concerns
The battery management system in the battery may also have limits for batteries in series, so read carefully about the instructions provided by batteries manufacturers.
- Safety
Batteries can be connected in series, but too many of them in series may increase the risk of the battery strings.
Please ensure that you totally understand the battery specifications, status, and requirements of your application for better use of the batteries.
How to connect batteries in parallel?
Connection of batteries in parallel increases the current of the battery strings. For example, when you connect three 12V 100Ah batteries in parallel, you will get 12V 300Ah, the total amount of power is 3600VAH, 3.6KW.
Wire the batteries in parallel, step by step:
- Connect the positive terminal of the first battery to the positive terminal of the second battery;
- Connect the negative terminal of the first battery to the negative terminal of the second battery, and connect more batteries in this way;
- Wire the negative terminal of the first battery to the negative terminal of your load, and wire the positive terminal of the first battery to the positive terminal of your load.
Advantages of batteries in parallel
Batteries in parallel can get the higher current you need to power your specific appliance when one battery can not meet your requirements. The resistance of the battery strings is lowered, allowing for better current flow, if one battery fails, the others can still work normally, which is better than the batteries in series.
Disadvantages of batteries in parallel
Parallel connection of the batteries does not increase the voltage, it increases the current, if one battery shorts, it can affect the whole battery strings. So the management of the batteries in parallel becomes complex, it needs proper wiring and monitoring to ensure the safe status of the batteries.
Wire batteries with different capacities in parallel, is it right?
When you connect many batteries in parallel, you will get a higher current, but here are some issues that you need concerned about when you wire batteries with different capacities.
- Uneven discharging
Batteries with different capacities will discharge at different rate. The batteries with lower capacities will drain faster than those batteries with higher capacities, thus leading to over-discharge issues and affect the whole performance of the batteries strings.
- Reduced Efficiency
The batteries with different capacities can result in inefficient use of total power and may lead to reduced efficiency of the battery strings.
- Reduced Lifespan
The batteries in parallel with different capacities may lead to reducing the lifespan in the long run.
- Safety Issue Concerns
The imbalanced capacities of the batteries in series may lead to overheating, damage, fire or safety hazards.
In conclusion, connecting batteries with different capacities is not recommended.
How many batteries are suitable for wiring in parallel?
Considering batteries quantities in parallel depends on many factors,
- Power Requirements
Connect batteries in parallel increase the current the battery strings, the quantities of the parallel batteries depends on your specific application needs. For lithium batteries with BMS, please refer to ponint 4.
- Charging and Discharging Capability
Ensure that the charging and discharging of the batteries in parallel can handle the combined capacity.
- Battery specifications
Please refer to the battery specification from the manufacturer, there will be written in detail about the parallel connection, current and voltage limits in the user instructions.
- Battery Management System
The BMS board will have limits on quantity of batteries in parallel, for our lead acid replacement lifepo4 batteries, we support 4 units in parallel, and for home energy storage batteries, we support 15 units in parallel.
In general, it is important to analyze your specific application requirements and know well about the batteries info provided from the battery manufacturers to decide the number of batteries in parallel.
Batteries in series or in parallel, which is better?
It’s hard to say whether it is better to connect batteries in series or in parallel. It depends on you application specification needs as well as the batteries themselves. Batteries in series is suitable for cases where higher voltage are required, and batteries in parallel is suitable for cases where higher current and flexibility in voltage are required.
It is important to weigh the advantages and disadvantages of the batteries in series or in parallel carefully as well as to communicate and understand well from the manufacturers before making an informed decision.
Do batteries last longer in series or in parallel?
Whether the batteries in series or in parallel last longer depends on several factors, such as the quantity, the chemical materials, the depth of discharge, and charging and discharging rate, and so on. Only proper management and monitoring systems can help extend the lifespan of batteries regardless of whether they are connected in series or parallel.
Is it possible to wire batteries in series and parallel at the same time?
Yes. It is possible to connect batteries both in series and in parallel. This type of connection ensure you to get the higher voltage and higher current at the same time. For example, you need 51.2V 300Ah power, and you have 12.8V 100Ah batteries, now connect 4 batteries in series as the first battery string to get 51.2V, and connect 3 battery strings(51.2V 100Ah) in parallel to get the battery pack 51.2V 300Ah, the total number of the battery 12.8V 100Ah you need is 4*3 = 12 units. And ensure these batteries are of same type and with proper operation first.
Choose reliable solar batteries for your energy storage system
HBOWA has been dedicated to solar energy systems for many years. Our product lines include solar batteries, home energy storage batteries, solar inverters, solar panels, and solar systems. Solar batteries are the key components in solar power systems, we always strictly control the production process to ensure you get stable and reliable solar batteries. If you have any concerns about our solar batteries, feel free to contact us directly.
