Series, Parallel and Series-Parallel Connection of Batteries

Series, Parallel & Series-Parallel Configuration of Batteries

Introduction to Batteries Connections

One may think what is the purpose of series, parallel or series-parallel connections of batteries or which is the right configuration to charge storage, battery bank system, off grid system or solar panel installation. Well, It depends on the system requirement i.e. to increase the voltages by series connection of batteries, battery ampere hours (as batteries are rated in Ah instead of Amperes) or simply the current or power of batteries by connecting the batteries in parallel or series-parallel to maintain the system according to your needs. If you need to know how to do it, read the following step by step tutorial about primary (non-rechargeable like AAA cells) and secondary (rechargeable like Lead Acid, Nickel Cadmium, Nickel Metal Hydride, Lithium-Ion etc) batteries configuration.

We received some confusing circuits about the topic and they ask if the batteries connections are in series, parallel or series-parallel and which one they go for?. So we will discuss the series, parallel and series parallel connection of batteries in details with schematic diagrams and applications.

• Related Post: Why We can’t store AC in Batteries instead of DC?

Now let’s begin…

Types of Battery Connections

There are three basic types of batteries connection.

1. Series Connection
2. Parallel Connection
3. Series-Parallel Connection

Click image to enlarge

• Related Post: Introduction to Series, Parallel and Series-Parallel Connections

Below is the comprehensive detail about each connection.

Series Connection of Batteries

If we connect the positive (+) terminal of battery to negative (-) and negative to positive terminal as shown in the below fig, then the batteries configuration would be in series.

Good to know:

In series connection of batteries, current is same in each wire or section while voltage is different i.e. voltages are additive e.g.

V₁ + V₂ + V₃….Vn

In below figure, two batteries each of 12V, 200Ah are connected in Series. So the total effective Ampere-hour (Ah) would be same while Voltage is additive.

i.e.

= 12V + 12V = 24V,  200Ah

Click image to enlarge

• Related Tutorial: A Complete Guide about Solar Panel Installation with Batteries. Step by Step Procedure with Calculation & Diagrams

When We Need & How to Connect Batteries in Series?

When you need to double the voltage level according to your system needs while maintain the same capacity or ampere hour (Ah) rating of batteries.

For example, If you have two 12V, 200Ah hour batteries and you need 24V system for installation. Simply, connect both of the batteries in series where you will get 24V and the same ampere hour rating i.e. 200Ah.

Keep in mind that battery discharge slowly in series connection as compared to parallel batteries connection.

You can do it with any number of batteries i.e. to get 36V, 48V, 72V DC and so on by connecting batteries in series.

This system is used in different solar panel installations and other applications.

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Parallel Connection of Batteries

If we connect the positive terminal (+) of battery to positive and negative (-) to negative terminal. Then the batteries configuration would be in parallel.

Good to know:

In parallel connection, voltage will be same in each wire or section, while current will be different i.e. current is additive.

e.g.

I₁+I₂+I₃…+In

In below figure, two batteries each of 12V, 200Ah are connected in parallel. So the total effective Voltage would be same while Ampere-hour is additive.

i.e.

= 200Ah +200Ah = 400Ah, 12V.

Click to image to enlarge

• Related Post: How to Calculate the Battery Charging Time & Battery Charging Current – Examples

When We Need & How to Connect Batteries in Parallel?

When you need to double the battery capacity or ampere hours (Ah) rating according to your system needs while maintain the same level of voltages.

For example, If you have two 12V, 200Ah hour batteries and you need 12V system for installation. Simply, connect both of the batteries in parallel where the overall battery capacity would be 400Ah and the same voltage level i.e. 12V.

Keep in mind that battery discharge quickly in parallel  as compared to series batteries connection.

You can do it with any number of batteries i.e. to get the same level of voltage while increase the battery capacity in ampere hours in parallel batteries connection.

This system is used in different solar panel installations and other applications.

• Related Post: Difference Between a Battery and a Capacitor

Series-Parallel Connection of Batteries

If we connect two pairs of two batteries in series and then connect these series connected batteries in parallel, then this configuration of batteries would be called series-parallel connection of batteries.

In other words, It is series, nor parallel circuit, but known as series-parallel circuit. Some of the components are in series and other are in parallel or complex circuit of series and parallel connected devices and batteries.

Related Post:

• Series Connection of Solar Panel & Batteries with Auto UPS System
• Parallel Connection of Batteries with Solar Panel & Auto UPS
  

In below figure,.

Six (6) batteries each of 12V, 200Ah are connected in Series-Parallel configuration.

i.e.

• B₁ & B₂ in Series … 12V + 12V = 24V, 200Ah …Series Connection
• B₃ & B₄ in Series … 12V + 12V = 24V, 200Ah …Series Connection
• B₅ & B₆ in Series … 12V + 12V = 24V, 200Ah …Series Connection

And then the pair of these batteries are connected in parallel i.e. two parallel sets of three batteries are connected in series.

i.e.

Set 1 = B₁, B₃, B₅ = Series

Set 2 = B₂, B₄, B₆ = Series

And then,

Set 1 & Set 2 = In Parallel.

So the effective voltage and Ampere-hour would be

Ampere hour (Ah )= 200Ah + 200Ah + 200Ah = 600Ah

Voltages = 12V + 12V = 24V. (Parallel connection)

Click image to enlarge

Batteries Related Calculators:

• Battery Life Calculator
• Battery Capacity Calculator

When We Need & How to Connect Batteries in Series-Parallel?

When you need to double the battery capacity or ampere hours (Ah) rating as well as batteries voltages according to your system needs.

For example, If you have six batteries each of 12V, 200Ah hour and you need 600Ah capacity and 24V system for installation. Now you have two sets of three batteries, simply, connect two sets of three batteries in series and then connect the two set in parallel (as shown in fig above) where the overall battery capacity would be 600Ah and level of voltages would be 24V.

You can do it with any number of batteries i.e. to get different level of voltages as well as increase the battery capacity in ampere hours in series-parallel connection of batteries.

This system is used in different solar panel installations and other applications.

Comparison of Series, Parallel & Series-Parallel Connection

The given table below would show the main different between series and parallel connection.

Click image to enlarge

• Related Tutorials: Batteries Wiring and Installation Diagrams

General Precautions & Instructions of Batteries Wiring & Installation

Warning & Instructions:

• Never ever short or touch the Positive (+) terminal of battery with Negative (-) terminal of battery to avoid short circuit, damage, injury, explosion or fire.
• Always connect the same voltage level and capacity of battery to avoid charging problems and shortened battery life.
• Don’t confuse (as it may be dangerous) with the complex wiring and connection of batteries in series-parallel. Always, do proper calculations and make schematic and diagrams of battery bank connections before implementing them in practical to be safe.
• Special care should be taken of polarity while charging the secondary batteries to avoid short circuit and hazardous condition.
• When battery gets fully charged, remove the charger to avoid overheating (In case of non automatic charger or charge controller).
• Always, charge battery at room temperature.
• Do not try to charge the primary cells. i.e. don’t charge the non-rechargeable batteries.
• Disconnect the battery from connected load if no longer in use to avoid corrosion and leakage.
• Disconnect the battery charging source and load before connecting or disconnecting terminals.

Related Batteries Connections & Wiring Tutorials:

• How to Design and Install a Solar PV System? With Solved Example
• How to Wire Solar Panel to 12V Battery and 12V DC Load?
• How to Wire Solar Panel to 220V Inverter, 12V Battery ,12V DC Load?
• Difference Between Series and Parallel Circuit – Comparison
• What Happens if a Battery is Connected to the AC Supply?
• What Happens to the Battery with Reverse Polarity Wiring Connection