# Battery Charge Time Calculator. 24v battery pack rechargeable

## How to connect batteries in series and parallel

If you have ever worked with batteries you have probably come across the terms series, parallel, and series-parallel, but what exactly do these terms mean?

Series, Series-Parallel, and Parallel is the act of connecting two batteries together, but why would you want to connect two or more batteries together in the first place?

By connecting two or more batteries in either series, series-parallel, or parallel, you can increase the voltage or amp-hour capacity, or even both; allowing for higher voltage applications or power hungry applications.

## CONNECTING BATTERIES IN SERIES

Connecting a battery in series is when you connect two or more batteries together to increase the battery systems overall voltage, connecting batteries in series does not increase the capacity only the voltage. For example if you connect four 12Volt 26Ah batteries you will have a battery voltage of 48Volts and battery capacity of 26Ah.

To configure batteries with a series connection each battery must have the same voltage and capacity rating, or you can potentially damage the batteries. For example you can connect two 6Volt 10Ah batteries together in series but you cannot connect one 6V 10Ah battery with one 12V 20Ah battery.

To connect a group of batteries in series you connect the negative terminal of one battery to the positive terminal of another and so on until all batteries are connected. You would then connect a link/cable to the negative terminal of the first battery in your string of batteries to your application, then another cable to the positive terminal of the last battery in your string to your application.

When charging batteries in series, you need to use a charger that matches the battery system voltage. We recommend you charge each battery individually to avoid battery imbalance.

Sealed lead acid batteries have been the battery of choice for long string, high voltage battery systems for many years, although lithium batteries can be configured in series, it requires attention to the BMS or PCM.

## CONNECTING BATTERIES IN PARALLEL

Connecting a battery in parallel is when you connect two or more batteries together to increase the amp-hour capacity. With a parallel battery connection the capacity will increase, however the battery voltage will remain the same.

Batteries connected in parallel must be of the same voltage, i.e. a 12V battery can not be connected in parallel with a 6V battery. It is best to also use batteries of the same capacity when using parallel connections.

For example, if you connect four 12V 100Ah batteries in parallel, you would get a 12V 400Ah battery system.

When connecting batteries in parallel, the negative terminal of one battery is connected to the negative terminal of the next and so on through the string of batteries. The same is done with positive terminals, i.e. the positive terminal of one battery to the positive terminal of the next.

For example, let’s say you needed a 12V 300Ah battery system. You will need to connect three 12V 100Ah batteries together in parallel.

Parallel battery configuration helps increase the duration in which batteries can power equipment, but due to the increased amp-hour capacity they can take longer to charge than series connected batteries. This time can safely be reduced, without damaging the batteries, by charging faster. Now that the battery is larger, a higher current charge is still the same percentage of the total capacity, and each battery ‘feels’ a smaller current.

While it is often debated what the best way to connect in parallel is, the above method is common for low current applications. For high current applications, talk to one of our experts as your situation may need a special configuration to ensure all of the batteries age at as similar as possible rates.

## SERIES – PARALLEL CONNECTED BATTERIES

Last but not least! There is series-parallel connected batteries. Series-parallel connection is when you connect a string of batteries to increase both the voltage and capacity of the battery system.

For example, you can connect six 6V 100Ah batteries together to give you a 12V 300Ah battery, this is achieved by configuring three strings of two batteries.

In this connection you will have two or more sets of batteries which will be configured in both series and parallel to increase the system capacity.

If you need any help with configuring batteries in series, parallel or series parallel please get in contact with one of our battery experts.

### LITHIUM BATTERIES YOU CAN CONNECT IN SERIES

Many brands of lithium batteries can not be connected in series or parallel due to their PCM or BMS configuration. Power Sonic’s PSL-SC series of lithium batteries can be connected in series or parallel, ideal for higher voltage or capacity applications.

### You may also be interested in…

The Comprehensive Guide to Level 2 EV Charging

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EV Charging Connector Types: A Complete Guide

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## The Power Sonic Brand Promise

### Quality

Manufactured using the latest technology and stringent quality control, our battery products are designed to exceed in performance and reliability.

### Experience

Our focused approach to exceptional end to end customer experience sets us apart from the competition. From enquiry to delivery and everything in-between we regularly exceed our customers’ expectations.

### Service

Delivery on time, every time to customer specifications. We pride ourselves on offering tailored service solutions to meet our customers’ exact specifications.

## Battery Charge Time Calculator

Use our battery charge time calculator to easily estimate how long it’ll take to fully charge your battery.

## Battery Charge Time Calculator

Tip: If you’re solar charging your battery, you can estimate its charge time much more accurately with our solar battery charge time calculator.

### How to Use This Calculator

Enter your battery capacity and select its units from the list. The unit options are milliamp hours (mAh), amp hours (Ah), watt hours (Wh), and kilowatt hours (kWh).

Enter your battery charger’s charge current and select its units from the list. The unit options are milliamps (mA), amps (A), and watts (W).

If the calculator asks for it, enter your battery voltage or charge voltage. Depending on the combination of units you selected for your battery capacity and charge current, the calculator may ask you to input a voltage.

Select your battery type from the list.

Optional: Enter your battery state of charge as a percentage. For instance, if your battery is 20% charged, you’d enter the number 20. If your battery is dead, you’d enter 0.

Click Calculate Charge Time to get your results.

## Battery Charging Time Calculation Formulas

For those interested in the underlying math, here are 3 formulas to for calculating battery charging time. I start with the simplest and least accurate formula and end with the most complex but most accurate.

### Formula 1

Formula: charge time = battery capacity ÷ charge current

Accuracy: Lowest

Complexity: Lowest

The easiest but least accurate way to estimate charge time is to divide battery capacity by charge current.

Most often, your battery’s capacity will be given in amp hours (Ah), and your charger’s charge current will be given in amps (A). So you’ll often see this formula written with these units:

charge time = battery capacity (Ah) ÷ charge current (A)

However, battery capacity can also be expressed in milliamp hours (mAh), watt hours (Wh) and kilowatt hours (kWh). And your battery charger may tell you its power output in milliamps (mA) or watts (W) rather than amps. So you may also see the formula written with different unit combinations.

charge time = battery capacity (mAh) ÷ charge current (mA) charge time = battery capacity (Wh) ÷ charge rate (W)

And sometimes, your units are mismatched. Your battery capacity may be given in watt hours and your charge rate in amps. Or they may be given in milliamp hours and watts.

In these cases, you need to convert the units until you have a ‘matching’ pair.- such as amp hours and amps, watt hours and watts, or milliamp hours and milliamps.

For reference, here are the formulas you need to convert between the most common units for battery capacity and charge rate. Most of them link to our relevant conversion calculator.

Battery capacity unit conversions:

• watt hours = amp hours × volts
• amp hours = watt hours ÷ volts
• milliamp hours = amp hours × 1000
• amp hours = milliamp hours ÷ 1000
• watt hours = milliamp hours × volts ÷ 1000
• milliamp hours = watt hours ÷ volts × 1000
• kilowatt hours = amp hours × volts ÷ 1000
• amp hours = kilowatt hours ÷ volts × 1000
• watt hours = kilowatt hours × 1000
• kilowatt hours = watt hours ÷ 1000

Charge rate unit conversions:

The formula itself is simple, but taking into account all the possible conversions can get a little overwhelming. So let’s run through a few examples.

### Example 1: Battery Capacity in Amp Hours, Charging Current in Amps

Let’s say you have the following setup:

• Battery capacity: 100 amp hours
• Charging current: 10 amps

To calculate charging time using this formula, you simply divide battery capacity by charging current.

In this scenario, your estimated charge time is 10 hours.

### Example 2: Battery Capacity in Watt Hours, Charging Rate in Watts

Let’s now consider this scenario:

Because your units are again ‘matching’, to calculate charging time you again simply divide battery capacity by charging rate.

In this scenario, your estimated charge time is 8 hours.

### Example 3: Battery Capacity in Milliamp Hours, Charging Rate in Watts

Let’s consider the following scenario where the units are mismatched.

First, you need to decide which set of matching units you want to convert to. You consider watt hours for battery capacity and watts for charge rate. But you’re unable to find the battery’s voltage, which you need to convert milliamp hours to watt hours.

You know the charger’s output voltage is 5 volts, so you settle on amp hours for battery capacity and amps for charge rate.

With that decided, you first divide watts by volts to get your charging current in amps.

Next, you convert battery capacity from milliamp hours to amp hours by dividing milliamp hours by 1000.

Now you have your battery capacity and charging current in ‘matching’ units. Finally, you divide battery capacity by charging current to get charge time.

In this example, your estimated battery charging time is 1.5 hours.

### Formula 2

Formula: charge time = battery capacity ÷ (charge current × charge efficiency)

Accuracy: Medium

Complexity: Medium

No battery charges and discharges with 100% efficiency. Some of the energy will be lost due to inefficiencies during the charging process.

This formula builds on the previous one by factoring in charge/discharge efficiency, which differs based on battery type.

Here are efficiency ranges of the main types of rechargeable batteries (source):

Note: Real-world charge efficiency is not fixed and varies throughout the charging process based on a number of factors, including charge rate and battery state of charge. The faster the charge, typically the less efficient it is.

### Example 1: Lead Acid Battery

Let’s assume you have the following setup:

To calculate charging time using Formula 2, first you must pick a charge efficiency value for your battery. Lead acid batteries typically have energy efficiencies of around 80-85%. You’re charging your battery at 0.1C rate, which isn’t that fast, so you assume the efficiency will be around 85%.

With an efficiency percentage picked, you just need to plug the values in to the formula.

100Ah ÷ (10A × 85%) = 100Ah ÷ 8.5A = 11.76 hrs

In this example, your estimated charge time is 11.76 hours.

Recall, that, using Formula 1, we estimated the charge time for this setup to be 10 hours. Just by taking into account charge efficiency our time estimate increased by nearly 2 hours.

### Example 2: LiFePO4 Battery

Let’s assume you again have the following setup:

Based on your battery being a lithium battery and the charge rate being relatively slow, you assume a charge efficiency of 95%. With that, you can plug your values into Formula 2.

1200Wh ÷ (150W × 95%) = 1200Wh ÷ 142.5W = 8.42 hrs

In this example, your estimated charge time is 8.42 hours.

Using Formula 1, we estimated this same setup to have a charge time of 8 hours. Because lithium batteries are more efficient, factoring in charge efficiency doesn’t affect our estimate as much as it did with a lead acid battery.

### Example 3: Lithium Ion Battery

Again, let’s revisit the same setup as before:

First, you need to assume a charge efficiency. Based on the battery being a lithium battery and the charge rate being relatively fast, you assume the charge efficiency is 90%.

As before, you need to ‘match’ units, so you first convert the charging current to amps.

Then you convert the battery’s capacity from milliamp hours to amp hours.

With similar units, you can now plug everything into the formula to calculate charge time.

3Ah ÷ (2A × 90%) = 3Ah ÷ 1.8A = 1.67 hours

In this example, your estimated charge time is 1.67 hours.

### Formula 3

Formula: charge time = (battery capacity × depth of discharge) ÷ (charge current × charge efficiency)

Accuracy: Highest

Complexity: Highest

The 2 formulas above assume that your battery is completely dead. In technical terms, this is expressed by saying the battery is at 100% depth of discharge (DoD). You can also describe it as 0% state of charge (SoC).

Formula 3 incorporates DoD to let you estimate charging time regardless of how charged your battery is.

### Example 1: 50% DoD

Let’s revisit this setup, but this time assume our lead acid battery has a 50% DoD. (Most lead acid batteries should only be discharged to 50% at most to preserve battery life.)

As before, let’s assume a charging efficiency of 85%.

We have all the info we need, so we just plug the numbers into Formula 3.

(100Ah × 50%) ÷ (10A × 85%) = 50Ah ÷ 8.5A = 5.88 hrs

In this example, your battery’s estimated charge time is 5.88 hours.

### Example 2: 80% DoD

For this example, imagine you have the following setup:

As before, we’ll assume that the charging efficiency is 95%.

With that in mind, here’s the calculation you’d do to calculate charge time.

(1200Wh × 80%) ÷ (150W × 95%) = 960Wh ÷ 142.5W = 6.74 hrs

In this example, it will take about 6.7 hours to fully charge your battery from 80% DoD.

### Example 3: 95% DoD

Let’s say your phone battery is at 5%, meaning it’s at a 95% depth of discharge. And your phone battery and charger have the following specs:

As before, we need to convert capacity and charge rate to similar units. Let’s first convert battery capacity to amp hours.

Next, let’s convert charge current to amps.

Because the charge C-rate is relatively high, we’ll again assume a charging efficiency of 90% and then plug everything into Formula 3.

(3Ah × 95%) ÷ (2A × 90%) = 2.85Ah ÷ 1.8A = 1.58 hrs

Your phone battery will take about 1.6 hours to charge from 5% to full.

### Why None of These Formulas Is Perfectly Accurate

None of these battery charge time formulas captures the real-life complexity of battery charging. Here are some more factors that affect charging time:

• Your battery may be powering something. If it is, some of the charge current will be siphoned off to continue powering that device. The more power the device is using, the longer it will take for your battery to charge fully.
• Battery chargers aren’t always outputting their max charge rate. Many battery chargers employ charging algorithms that adjust the charging current and voltage based on how charged the battery is. For example, some battery chargers slow the charge rate down drastically once the battery reaches around 70-80% charged. These charging algorithms vary based on charger and battery type.
• Batteries lose capacity as they age. An older battery will have less capacity than an identical new battery. Your 100Ah LiFePO4 battery may have only have around 85Ah capacity after 1000 cycles. And the rates at which batteries age depend on a number of factors.
• Lithium batteries have a Battery Management System (BMS). Besides consuming a modest amount of power, the BMS can adjust the charging current to protect the battery and optimize its lifespan. iPhones have a feature called Optimized Battery Charging that delays charging the phone’s battery past 80% until you need to use it.
• Lead acid battery chargers usually have a timed absorption stage. After being charged to around 70-80%, many lead acid battery chargers (and solar charge controllers) enter a timed absorption stage for the remainder of the charge cycle that is necessary for the health of the battery. It’s usually a fixed 2-3 hours, regardless of how big your battery is, or how fast your charger.

In short, batteries are wildly complex, and accurately calculating battery charge time is no easy task. It goes without saying that any charge time you calculate using the above formulas.- or our battery charge time calculator.- should be viewed as an estimate.

## How to connect batteries in series and parallel

If you have ever worked with batteries you have probably come across the terms series, parallel, and series-parallel, but what exactly do these terms mean?

Series, Series-Parallel, and Parallel is the act of connecting two batteries together, but why would you want to connect two or more batteries together in the first place?

By connecting two or more batteries in either series, series-parallel, or parallel, you can increase the voltage or amp-hour capacity, or even both; allowing for higher voltage applications or power hungry applications.

## CONNECTING BATTERIES IN SERIES

Connecting a battery in series is when you connect two or more batteries together to increase the battery systems overall voltage, connecting batteries in series does not increase the capacity only the voltage. For example if you connect four 12Volt 26Ah batteries you will have a battery voltage of 48Volts and battery capacity of 26Ah.

To configure batteries with a series connection each battery must have the same voltage and capacity rating, or you can potentially damage the batteries. For example you can connect two 6Volt 10Ah batteries together in series but you cannot connect one 6V 10Ah battery with one 12V 20Ah battery.

To connect a group of batteries in series you connect the negative terminal of one battery to the positive terminal of another and so on until all batteries are connected. You would then connect a link/cable to the negative terminal of the first battery in your string of batteries to your application, then another cable to the positive terminal of the last battery in your string to your application.

When charging batteries in series, you need to use a charger that matches the battery system voltage. We recommend you charge each battery individually to avoid battery imbalance.

Sealed lead acid batteries have been the battery of choice for long string, high voltage battery systems for many years, although lithium batteries can be configured in series, it requires attention to the BMS or PCM.

## CONNECTING BATTERIES IN PARALLEL

Connecting a battery in parallel is when you connect two or more batteries together to increase the amp-hour capacity. With a parallel battery connection the capacity will increase, however the battery voltage will remain the same.

Batteries connected in parallel must be of the same voltage, i.e. a 12V battery can not be connected in parallel with a 6V battery. It is best to also use batteries of the same capacity when using parallel connections.

For example, if you connect four 12V 100Ah batteries in parallel, you would get a 12V 400Ah battery system.

When connecting batteries in parallel, the negative terminal of one battery is connected to the negative terminal of the next and so on through the string of batteries. The same is done with positive terminals, i.e. the positive terminal of one battery to the positive terminal of the next.

For example, let’s say you needed a 12V 300Ah battery system. You will need to connect three 12V 100Ah batteries together in parallel.

Parallel battery configuration helps increase the duration in which batteries can power equipment, but due to the increased amp-hour capacity they can take longer to charge than series connected batteries. This time can safely be reduced, without damaging the batteries, by charging faster. Now that the battery is larger, a higher current charge is still the same percentage of the total capacity, and each battery ‘feels’ a smaller current.

While it is often debated what the best way to connect in parallel is, the above method is common for low current applications. For high current applications, talk to one of our experts as your situation may need a special configuration to ensure all of the batteries age at as similar as possible rates.

## SERIES – PARALLEL CONNECTED BATTERIES

Last but not least! There is series-parallel connected batteries. Series-parallel connection is when you connect a string of batteries to increase both the voltage and capacity of the battery system.

For example, you can connect six 6V 100Ah batteries together to give you a 12V 300Ah battery, this is achieved by configuring three strings of two batteries.

In this connection you will have two or more sets of batteries which will be configured in both series and parallel to increase the system capacity.

If you need any help with configuring batteries in series, parallel or series parallel please get in contact with one of our battery experts.

### LITHIUM BATTERIES YOU CAN CONNECT IN SERIES

Many brands of lithium batteries can not be connected in series or parallel due to their PCM or BMS configuration. Power Sonic’s PSL-SC series of lithium batteries can be connected in series or parallel, ideal for higher voltage or capacity applications.

### You may also be interested in…

The Comprehensive Guide to Level 2 EV Charging

This comprehensive guide on Level 2 charging for electric vehicles (EVs) covers everything from Level 2 charging speeds and charger types to…

EV Charging Connector Types: A Complete Guide

Electric vehicles (EVs) continue to grow in popularity worldwide due to their clean energy and efficient performance. However, with the incr…

The Benefits of Offering EV Charging at Hotels

As the world moves towards a more sustainable future, electric vehicles (EVs) are becoming increasingly popular. The growth of EV numbers pr…

## The Power Sonic Brand Promise

### Quality

Manufactured using the latest technology and stringent quality control, our battery products are designed to exceed in performance and reliability.

### Experience

Our focused approach to exceptional end to end customer experience sets us apart from the competition. From enquiry to delivery and everything in-between we regularly exceed our customers’ expectations.

### Service

Delivery on time, every time to customer specifications. We pride ourselves on offering tailored service solutions to meet our customers’ exact specifications.

## Rechargable 12V/24V Lithium-Ion Battery Pack for LED Strip Lights

Buy any LED channel and get 10% off any LED strip.

## Rechargable 12V/24V Lithium-Ion Battery Pack for LED Strip Lights

Channel Strip Combo Discount!

Buy any LED channel and get 10% off any LED strip.

Battery and charger only. LED strip lights and other accessories sold separately

### Description

This rechargeable Lithium-ion battery pack is the ideal portable replacement for standard AC powered LED drivers. This high-capacity rechargeable battery pack offers 12V DC and 24V DC outputs for maximum compatibility with your LED strip lights or LED modules.

You can use this battery solution to power portable LED strip light projects such as portable barbecue lights and portable LED camping or RV lights. Combine it with one of our Casambi wireless Bluetooth RGB controllers to create the ultimate rechargeable LED lamp!

The DC barrle jack outputs integrate easily with LED light bars and flexible LED strip lights or modules. In addition, this battery pack also offers a USB 5V DC output which can be used to charge mobile phones, Bluetooth speakers and other personal electronics.

The battery is designed for with slow charge process (5 hours for full charge) which helps the battery pack to have a long lifespan.

### General Specifications

• Recharging:
• Voltage: 29.4V DC
• Current: 0.95A
• Voltage: 24V DC nominal (unregulated 29.4V. 21V)
• Current: 3A max
• Voltage: 12V DC (regulated)
• Current: 2A max
• Voltage: 5V DC
• Current: 2A max
• 1x Rechargeable battery pack
• 1x DC5525 male to DC5521 male power cable
• 1x DC5521 female to 2 male splitter cable
• 1x 29.4V AC/DC charging power supply

### Important notes

• DO NOT DISPOSE OF LITHIUM-ION PRODUCTS IN WATER OR FIRE
• Items in stock are shipped the same day from Knoxville, Tennessee, United States.
• Bulk pricing is available on request

### Common search terms

LED strip battery, Portable LED strip light, Battery LED strip lights, Battery powered LED strip lights, Rechargeable LED strip lights, Battery powered strip light, Outdoor portable LED lights

We cannot ship rigid items over 2.4m (8ft) in length due to freight restrictions. These products are offered for customer pickup only. Please refer to our Shipping Policy for further information.