Best Laptop Power Banks in 2022 – Buying Guide

If you use a laptop you are probably familiar with one of 2 these situations:

  1. Your laptop is going to run out of battery and you forgot its charger at home.
  2. Your laptop battery is old (needs to be replaced) and you always need to plug it into the wall.

Well, besides charging mobile phones and other gadgets, did you know you can use a power bank to charge a laptop?

Certainly, a power bank can perform the same function as a laptop charger, although you should know that, obviously, its power is limited and not just any model will do.

For a power bank to really work as a replacement for a charger, it must meet a series of requirements:

  1. Connector: include a cable with a connector compatible with the laptop’s charging port.
  2. Voltage (V): same working voltage.
  3. Power (W): same or greater power supplied.

In this guide, we will learn how to identify a laptop power bank taking into account the above requirements, and, as always, we will recommend the best models available on Amazon.

Features of a laptop charger

First of all, we need to know the specifications of our laptop charger in order to find a power bank that meets the same requirements.

In the following image we can see the specifications of a laptop charger:

Technical specifications of a laptop charger
Technical specifications of a laptop charger

We must check the output parameters (Output):

  • Voltage: 19.5V
  • Current/Amperage: 4.62A

This means that this charger works at a voltage of 19.5V (volts) and supplies a maximum current of 4.26A (amps).

This charger does not indicate the maximum power that it can supply but we can easily obtain it by multiplying the voltage by the current:

  • Power: 19.5V x 4.62A = 90W

With this information, we already know the charging voltage (19.5V) of our laptop and the recommended power (90W) that our power bank should supply.

It is very important to know this voltage because if we connect it to a charger (or power bank) that works at a higher voltage we could damage it irreversibly.

Using a power bank as a laptop charger

Next, we need to find a power bank that replaces our charger and meets the following characteristics:

Charging port

A laptop can be powered through a power bank in 3 different ways, depending on the OUTPUT port it has:

Types of laptop power banks with DC, AC and USB-C PD output ports
Types of laptop power banks with DC, AC, and USB-C PD output ports

There are 3 types of laptop power banks on the market:

1. Power bank with DC port

If we use a specific power bank with a DC output it is important to check its output voltage and if it includes a connector compatible with the charging port of your laptop.

Although, generally, this type of model usually includes a set of adapters compatible with the main laptop brands:

Power bank con 2 puertos de salida DC

Their main disadvantages are:

  1. The difficulty in finding a model compatible with the laptop (either by the output voltage or the connector).
  2. They require a specific AC charger to recharge them (like a laptop charger).
  3. They are usually very bulky.
2. Power bank with an AC port

Another option is those power banks that include a 220V AC port.

In this case, we do not have to worry about incompatibilities since we can directly connect the charger of our laptop (or any other device) as if we were doing it to the wall socket. Sounds good right?

Power banks with an AC 220V output port
Power banks with an AC 220V output port

However, there are also some drawbacks:

  1. Large dimensions
  2. Adding an additional AC charger
  3. Part of the energy of the power bank is lost when using the charger of the device (in this case the laptop) as an intermediary.
3. Power bank with USB-C PD port

A new way to power your laptop is by using a power bank with a USB-C output port with Power Delivery charging technology.

Power banks with USB-C PD output port
Power banks with USB-C PD output port

USB Type-C (USB-C) is the future of connectivity, allowing you to connect and charge any type of device (mobile, tablet, laptop, camera…) using a single universal power port, forget about searching for cables and compatible connectors.

On the other hand, Power Delivery (PD) is the technology that allows powering high-power devices – such as a laptop, through the USB-C port.

USB Power Delivery ejemplos de uso

Nowadays there are many new generation laptops that use USB Type-C as a power port. In these cases, you simply need to look for a power bank with Power Delivery that is compatible with the charging voltage of your laptop.

But, what if my laptop does not have a USB-C charging port?

Is it possible to charge it with a power bank with USB-C PD?

Laptop with DC port vs. USB-C port
Laptop with DC port vs. USB-C port

We are aware that many users do not have a last-generation laptop, in this case, we would need to use a special adapter or cable that has a USB-C connector (power bank) on one end and an INPUT DC connector (laptop) on the other end.

Adapter and cable from USB-C PD to DC connector
Adapter and cable from USB-C PD to DC connector

This adapter or cable incorporates a trigger capable of demanding power in Power Delivery to the power bank at a certain voltage: to date, we have found 2 models for 15V and 20V, but we do not know if in the future they will be manufactured at other voltages.

For this reason, we must pay attention to the voltage when buying this cable, since if we make a mistake in choosing it we could seriously damage our laptop.

For example:

If we connect a 15V PD trigger cable to a laptop charging at 20V, it will not be able to start charging => for a 20V laptop we need a 20V PD trigger cable.

On the other hand, if we connect a 20V PD trigger cable to a laptop charging at 15V, WE COULD IRREVERSIBLY DAMAGE OUR LAPTOP => for a 15V laptop we need a 15V PD trigger cable.

Output port voltage (V) ❗

Depending on the type of power bank we need to check for which voltages its output port works to know if it is compatible with the charging voltage of our laptop:

If we use a power bank with AC output port it is not necessary to check the voltage because we would still power the laptop with its own charger (which is already in charge of transforming the 220V voltage to the charging voltage of the laptop).

On the other hand, if we choose to buy a power bank with DC or USB-C PD output port, it is very important to check that this port has the same voltage* as your laptop charger, otherwise you could irreversibly damage your laptop.

This output voltage will always be indicated in the power bank specifications as “DC Output” or “USB-C Output”.

Output voltage on power banks with DC and USB-C PD port
Output voltage on power banks with DC port (left) and USB-C PD (right)
What happens if my laptop charges at a voltage of 19.5V*?

Actually, any electronic device must withstand a voltage of +-10% of its nominal voltage, that is:

If your laptop charges at 19.5V, it can take a maximum voltage of 21.45V (19.5V+1.95V), therefore, a 20V power bank could be connected to it.

In addition, it is necessary to take into account the voltage drop that occurs in the cable connecting the power bank and the laptop, which varies between 0.15 and 0.2V (depending on the resistance of the cable itself) for each meter of length.

For example, if the output voltage of the power bank is 20V, the laptop would receive a voltage of 19.8V (20V-0.2V).

On the other hand, we can also find models that may have one or more DC output ports with a fixed voltage or a single multi-voltage DC port, whose voltage can be selected (by pressing the “Power” button) to the charging voltage of our laptop.

Power bank with multi-voltage DC port
Left: Power bank with 2 fixed voltage DC ports: 12V and 20V Right: Power bank with multi-voltage DC port: 9V/12V/16V/19V/20V

Obviously, if we were to use a power bank with AC output it is not necessary to check the voltage because we would continue to power the laptop with its own charger (which is already in charge of transforming the 220V voltage to the computer charging voltage).

Power supplied (W)

Finally, we must take into account the maximum power that can be supplied by the output port of the power bank:

Maximum power in laptop power banks
Maximum power in power banks with DC (130W), AC (85W), and USB-C PD (45W) output ports respectively.

If the charger of our laptop is 65W then it is advisable to use a power bank that is capable of providing the same or higher power than the charger, because, otherwise, the computer would not even start up as it needs the maximum power during its start-up (and subsequent use) at the same time as it recharges its battery.

However, in the following section we will look at some situations in which it is possible to use a lower power model:

How much power does a power bank need to charge a laptop?

Depending on the laptop model, its charger will be designed to supply a maximum power, i. e: 45, 65, 90, or even 130 watts (W).

We may not find a power bank that provides the same or a higher power than our laptop charger either by specifications or budget. In this situation, we can also buy a lower-powered power bank.

Let’s say we are working in a coffee shop with our Lenovo Z50-70 laptop (its charger is 65W) and we run out of battery.

We could use a 65W power bank or resort to a lower power one, for example, 45W, to be used under certain conditions:

1. Removing the laptop battery

If we remove the battery from the laptop, the power of the power bank needed to continue working with the laptop will be lower than the power provided by its charger, since in this case, the energy needed to recharge its battery is not necessary.

We should also consider, that the power required during the start-up of a laptop is always higher than the average working power, due to the extra current peak that is produced.

A little trick to avoid the current peak at start-up would be to activate the sleep mode when the laptop indicates that its battery is running low. (Normally it goes to sleep a few seconds after closing the lid if the laptop has been configured this way).

Next, we connect the power bank and then remove the battery from the laptop.

If we deactivate the sleep mode (open the lid) we could enjoy the energy of the power bank without “suffering” that extra consumption of energy during startup.

In this scenario, we could use a power bank that supplies at least 70% of the power of our laptop charger. That is to say, if our charger is 65W, the power of the power bank should be at least 45W.

2. Recharging the battery while the laptop is turned off

Another option would be to keep the laptop turned off while recharging.

In this case, we would only need the power required to recharge the laptop battery and we could use the same power bank as in the previous case (45W), i.e., supplying at least 70% of the power of our laptop charger.

3. Recharging the laptop while using it at the same time

If the 2 previous options do not convince you, it is possible to use a lower-powered power bank when the laptop battery is not completely discharged (usually less charging power is required after 50% battery).

This way, if we connect the power bank before the laptop battery is depleted, we also avoid the excess power demand during startup.

The problem lies in knowing our laptop’s starting peak and how much power it needs to recharge its battery when it is still half-charged. Measurements would have to be made and this is usually not within everyone’s reach.

For this reason, we think that the most advisable thing to do is to use a power bank with the same or higher power than the laptop charger in these scenarios.

How many hours would I be able to use a laptop with a power bank?

Let’s suppose we are interested in buying a power bank to charge our laptop and we want to know how much extra time we could continue working with the power bank connected.

First of all, it is important to consider the following questions for the right choice of power bank:

  1. To get an idea of the average power consumption of your laptop, what kind of tasks do you usually use your laptop for? For example: surfing the web, office, gaming, watching Netflix…
  2.  For your chosen tasks, how many hours does your laptop last with a 100% charged battery?
  3. What is your budget?
  4. What type of laptop power bank do you want to use, with DC, AC, or USB-C Power Delivery port?

Now, we are going to see an example using a laptop with the following features:

  • Brand: Acer
  • Model: Aspire E5-551-T2HE
  • Charger: 19V/3.42A (65 W)
  • Charging voltage: 19V
  • Battery capacity: 45Wh
  • Charging port: DC jack 5.5 x 1.7 mm
  • Regular Usage Tasks: office tasks and web surfing.
    • Battery life 100%: 3.5h

Although our Acer laptop has a DC charging port, we decided to purchase a power bank with a USB-C PD port along with a USB-C PD to DC adapter cable:

Next, let’s calculate the approximate time we can use our Acer Aspire E5 laptop with the Litionite Vulcan power bank:

Calculating the average power consumption of our laptop

If we don’t have enough knowledge or the necessary tools to measure exactly the average consumption of our computer, we can make an estimate taking into account:

  1. The energy stored in the laptop battery.
  2. The estimated duration time for the tasks we usually perform with our laptop.

The energy stored in the notebook battery – measured in watt-hours (Wh) – can be found in the specifications of the battery itself.

This data may be displayed directly or, if not, it must be calculated by multiplying the voltage (V) by the capacity (mAh) of the battery.

For example, in the battery specifications of the left image the energy stored in the battery would be 49 Wh while the image on the right would be 73.26 Wh (11.1V x 6600mAh / 1000).

Energy (Wh) stored in a laptop battery
Optional: check current energy stored in a laptop battery

The capacity of a laptop battery gradually decreases with use, consequently, the energy stored in the battery is less than that indicated in the specifications.

If you want to know the current capacity of your laptop battery and thus its stored energy, you can use a free program called HWINFO32. Just follow these steps:

  1. Download the portable version of the software from the official website. Choose the Local (USA) option.
  2. Unzip the downloaded file and run HWiNFO32.exe .
  3. Accept Windows permissions (it is a secure application, it only displays information about your system and components).
  4. The HWiNFO32 welcome screen opens, then press the Run key.
  5. On the left side of the main screen, click on the Smart Battery option.
  6. On the right side of the same screen, information about your laptop’s battery will appear:
    1. Designed capacity: this is the maximum capacity (mWh) that the battery had at the factory.
    2. Full charge capacity: is the current capacity (mWh) of the battery.
    3. Wear level: wear level (%) of the battery.

Once we know the energy stored in the laptop battery we must divide by the time (expressed in hours) that the laptop lasts when its battery is fully charged (100%):

Average Laptop Power Consumption (W) = Battery Energy (Wh) / Time of use (h)

In our example, the Acer Aspire E5 laptop battery is 45 Wh and we have about 3.5 hours to use it for everyday tasks before its battery is completely drained.

Therefore, our laptop consumes an average of 12.9 watts (W):

Acer Power Consumption = 45 Wh / 3.5 h = 12.9 W (watts)

DISCLAIMER:

Of course, the consumption of our laptop and, therefore, the battery life will vary depending on the tasks we are performing at that moment.

Surfing the web is not the same as playing a game that demands maximum CPU and GPU performance, for example.

Calculating the useful energy of a power bank for laptop charging

Once we have an estimate of the consumption of our laptop we will calculate the number of hours we could continue to use it with a power bank.

At first, one may think that one should simply apply the following formula:

Laptop usage time (h) = Power bank Energy (Wh) / Avg. Laptop Power Consumption (W) ERROR!

The above formula is not valid, as we must take into account the energy efficiency of the power bank and the laptop during the charging process as well as other factors that we will see below.

Stored energy and efficiency of a power bank

If the stored energy is not indicated in the specifications of the power bank, we can easily calculate it by multiplying the capacity of its internal battery (mAh) by its nominal voltage (V) and dividing the result by 1000:

Power Bank Stored Energy (Wh) = [Battery capacity (mAh) x Battery voltage (V) ] / 1000

The nominal battery voltage of a power bank is usually 3.7 volts, although we remind you that there are also models with 3.6, 3.8 or 3.85V batteries.

However, during the process of charging a device, this 3.7V must be transformed at the output port of the power bank to the charging voltage of the connected device, in this case, a laptop whose voltage range is usually between 12 and 20V.

For this reason, due to this voltage transformation, part of the energy stored in a power bank is lost during the charging process of the device, and, depending on its energy efficiency, the loss will be greater or lesser.

There are power banks that have an efficiency higher than 90% as well as those that have an efficiency below 80%, but if the model is of a good enough quality its efficiency will be around 85%.

For more information, we invite you to read our guide on the Actual capacity and energy efficiency of a power bank.

In conclusion, the energy supplied at the USB output port of a power bank will be different from the energy stored in its battery and can be calculated by the following formula:

Power bank Useful Energy = Stored Energy x Energy Efficiency

Therefore, following our example, the useful energy that the Litionite Vulcan power bank can supply to a device would be:

Litionite Useful Energy = (74 Wh x 85) / 100 = 62.9 Wh

Once we know the power consumption of our Acer Aspire E5 and the useful energy of the Litionite Vulcan power bank, we need to know the energy required to fully recharge the laptop battery.

Remember that a laptop with DC input can be powered through a power bank in three different ways, depending on the output port (OUTPUT) that the power bank has:

  • Power bank with DC port
  • Power bank with AC port
  • Power bank with USB-C PD port

Next, we are going to analyze the different “particularities” that our power bank may have depending on the output port used:

Laptop charging with Power bank with DC or USB-C PD port

In the case of using a power bank with DC or USB-C Power Delivery output, our laptop will also have an energy cost both in recharging its own battery and in powering the laptop itself.

Therefore, and for the same reasons stated above, the energy efficiency when recharging the battery or using the laptop will be around 85%.

Being the estimated useful energy for battery recharging or laptop use:

Useful Energy = Power bank Stored Energy x 0.85 (Power bank efficiency) x 0.85 (Laptop efficiency)

Or what is the same:

Useful Energy = Power bank Stored Energy x 0.7225

If we apply the first formula with the Litionite power bank the useful energy would be:

Litionite Useful Energy = 74 Wh x 0.85 x 0.85 = 53.5 Wh

Laptop charging with Power bank with AC port

If we use a power bank with an AC port, we can connect the laptop’s own charger to this output, just as we would connect it to a wall outlet.

In this case, in addition to the above, the efficiency of the charger itself should be added (we will also consider an efficiency of 85% for the charger) and, therefore, the estimated useful energy would be:

Useful Energy = Power bank Store Energy x 0.85 (Power bank efficiency) x 0.85 (Charger efficiency) x 0.85 (Laptop efficiency)

Or what is the same:

Useful Energy = Power bank Stored Energy x 0.6141

In the case of our example with the Litionite power bank, we see that the available energy is lower:

Litionite Useful Energy = 74 Wh x 0.85 x 0.85 x 0.85 = 45.44 Wh

As we can see, if we use a power bank with AC port the usage time to power a laptop will be shorter than in the case of using a power bank with DC or USB-C PD port due to the additional power loss in the charger.

However, the convenience of being able to use the laptop’s own charger saves us from having to use additional cables that match the DC power input of our computer.

In addition, we would not have to worry about having to take a power bank that would give us in its output the charging voltage that our laptop needs, since sometimes it is not an easy task to find it.

We should only look at the power delivered by the power bank and apply the same considerations that we have already seen in the section What is the power required to charge a laptop with a power bank?

Calculating the usage time of a laptop with a power bank

At this point, there are 3 different cases in the use of the useful energy of a power bank.

We will formulate each case to obtain a general formula for the usage time of a laptop with a power bank and then apply it to our example of the Acer Aspire E5 laptop and the Litionite Vulcan power bank.

In addition, we will compare the results obtained in each formula with the data we actually obtained in this example.

Finally, remember that this is not an exact calculation, we are talking about an estimate to help us know the approximate time of use before buying the power bank.

1. Removing the laptop battery

If we remove the battery of our laptop (in the case of being removable) and instead connect the power bank to power it, we would have an approximate time of use in hours:

Laptop usage time (h) = Power bank Useful Energy (Wh) / Avg. laptop power consumption (W)

If we apply the formula in our example:

  • Acer Aspire E5 (theoretical) usage time = 53.5 Wh / 12.9 W = 4.15 h (4h 9min)
  • Acer Aspire E5 usage time (actual) = 4h 37min
2. Recharging the battery with the laptop turned off

Another option is to recharge the battery with the laptop turned off, in this case, we can calculate the number of theoretical charges by applying the following formula:

Number of laptop charges = Power bank Useful Energy (Wh) / Laptop Battery Energy (Wh)

In our example:

  • Number of Acer Aspire E5 charges (theoretical) = 53.5 Wh / 45 Wh = 1.19 charges
  • Number of Acer Aspire E5 charges (actual) = 1.42 charges

We can see that with the Litionite power bank we would recharge 1.19 times the Acer laptop battery, i.e. we would obtain a 100% full charge and still have enough energy left over in the power bank (8.5 Wh) for another partial charge of the laptop:

Useful energy – Laptop battery energy = 53.5 Wh – 45 Wh = 8.5 Wh

We could also calculate the theoretical usage time with the number of charges and the average consumption of our laptop:

Laptop usage time (h) = No. of charges x Laptop battery energy (Wh) / Avg. laptop power consumption (W)

In our example:

  • Acer Aspire usage time (theoretical) = 1.19 x 45 Wh / 12.9 W = 4.15 h (4h 9min)
  • Acer Aspire usage time (actual) = 1.42 x 45 Wh / 12.9 W = 4.95 h (4h 57min)*

*As we can see it is 20 minutes longer than the actual usage time of case 1 with the laptop battery removed.

3. Recharging the laptop and using it at the same time

If we do not remove the battery (or it is not removable) and we use the computer while charging, the power bank will power the laptop both for use and for recharging the battery itself.

For example, the useful energy of the Litionite power bank (53.5 Wh) will be divided between the use of the Acer laptop itself (with an average power consumption of 12.9W) and the recharging of its battery (45Wh).

In this case, it is difficult to formulate a method to calculate the theoretical time of use of the laptop because the energy used to recharge its battery varies for each model since the recharging speed of the laptop will be different depending on the charging system implemented by the manufacturer. That is to say, a laptop can provide 15W in 1 hour to recharge its battery while another one can provide 35W.

In our example, we found that the Litionite power bank was able to power the Acer laptop for 1.83h (1h 50min) until its useful energy was exhausted.

In addition, during this time, Litionite recharged the laptop battery up to 82% of its energy (45Wh) which allowed us to continue working for almost 3 hours more on office tasks:

Usage time with laptop battery recharged to 82% = 45Wh x 0.82 / 12.9W = 2.86h

Therefore, the total time using our Acer laptop for office tasks was 4 hours and 41 minutes:

Acer Aspire usage time (actual) = 1.83h + 2.86h = 4.69h = 4 h 41 min

Conclusions and general formula

In the first 2 cases described, we saw that the theoretical usage time was similar while the actual usage time suffered small variations.

This is because we are working with real efficiencies, both in the laptop and in the power bank and, logically, they must differ from the theoretical efficiencies (85%) that we establish as a reference for the estimated calculation when we do not know the real efficiencies.

The most common is not knowing both the real efficiency of our computer and that of the power bank we are going to use to recharge it.

We also explained in Case 3 that it is not possible to use a general formula to predict the usage time because each laptop behaves differently during its battery recharge. However, the actual results obtained are similar to the first 2 cases.

Remember that the objective is to have an idea of the time of use of our laptop before buying a power bank, for this reason, we believe that the formula of case 1 is the best option for a quick estimate:

Laptop Usage Time (h) = Power bank Useful Energy (Wh) / Average Laptop Power Consumption (W)

Quick guide and real use cases 📝

In this section, we will try to summarize the essential content of this guide by linking to the sections you need to consult to buy a laptop power bank.

1. Choosing the type of laptop power bank

Depending on the type of output port of the power bank we will have to make several checks:

Option 1. Power bank with DC port
  1. Check the voltage (V) and power (W) of the laptop charger. Read this.
  2. Look for a power bank that has a DC output port with the same voltage (V) and power (W) equal to or higher than that charger. Possible problems:
    • “I can’t find a model with the same voltage as my charger”. Read this.
    • “I can’t find (or don’t want to spend much money) a model with the same power as my charger”. Read this.
  3. Check that the power bank has a cable and/or connector compatible with the charging port of the laptop.
Option 2. Power bank with AC port
  1. Check the power (W) of the laptop charger. Read here.
  2. Use an AC power bank with the same or higher power (W) than that charger. Possible problems:
    • “I can’t find (or don’t want to spend much money) a model with the same power as my charger”. Read this.
Option 3. Power bank with USB-C PD port
  1. Check the voltage (V) and power (W) of the laptop charger. Read this.
  2. Look for a power bank that has a USB Type-C output port with Power Delivery (PD) technology with the same voltage (V) and equal or higher power (W) than that charger. Possible problems:
    • “I can’t find a model with the same voltage as my charger”. Read this.
    • “I can’t find (or don’t want to spend much money) a model with the same power as my charger”. Read this.
  3. Charging cable:
    1. If the laptop has a USB-C charging port then there would be no problem, you can use the laptop’s own charging cable.
    2. If the laptop has a DC charging port then you must use a special cable with an adapter that converts from USB-C PD to DC (read this) and meets the following requirements:
      1. Have the same charging voltage as the laptop.
      2. Support the maximum power supplied by the power bank using Power Delivery technology.
      3. The DC connector of the cable is compatible with the DC port of the laptop.

2. Laptop usage time with a power bank

Once you have chosen the power bank, we will theoretically calculate the estimated time you could use your laptop for a certain regular activity (watching Netflix, Youtube, office tasks, surfing the Internet, playing online games…) depending on the charging method: laptop battery removed, laptop turned off or using the laptop while charging:

1. Calculate average consumption of the laptop
  1. Check the average duration (in hours) of the laptop with the battery fully charged (100%) according to the type of task usually performed.
  2. Check the energy (Wh) of the laptop battery. Read here.
  3. Apply formula:
    • Average Laptop Power Consumption (W) = Laptop Battery Energy (Wh) / Time of use (h)
2. Calculate useful energy of the power bank
  1. Check stored energy (Wh) of the power bank. Read here.
  2. Depending on the type of power bank, calculate energy to work with the laptop and/or to recharge its battery (read here):
    • Power bank with DC or USB-C PD port (read here):
      • Useful energy = Power bank energy x 0.7225
    • Power bank with AC port (read here)
      • Useful energy = Power bank energy x 0.6141
3. Calculate laptop usage time

Depending on the charging method of the laptop:

  • With the laptop battery removed:
    • Usage time (h) = Useful energy (Wh) / Average Laptop Power Consumption (W)
  • With the laptop turned off:
    • Number of charges = Useful energy (Wh) / Laptop Battery Energy
    • Usage time = No. of charges x Laptop Battery Energy (Wh) / Laptop Power Consumption (W)

3. Test results of charging a laptop with a power bank

Next, we are going to see the theoretical and real results obtained by charging some laptops with a power bank:

Lenovo Z50-70

Laptop:

  • Model: Lenovo Z50-70
  • Charger: 20V/2.25A (45W)
  • Charging voltage: 20V
  • Battery energy: 70Wh
  • Charging port: DC Lenovo (square jack)
  • Usual usage tasks: office automation with virtual machine (Virtual Box)
    • Battery life 100%: 2h 45min = 2.75h
    • Average laptop consumption: 70Wh /2.75 h = 25.5W

Power bank:

  • Model: Omars 20000mAh USB-C PD 45W
  • Battery capacity: [email protected] 72Wh
  • USB-C PD port: 5V/3A, 9V/3A, 12V/3A, 15V/3A, 20V/2.25A (45W max)
  • Charging voltages: 5V, 9V, 12V, 15V, 20V
  • Cable: USB-C PD to DC Lenovo 20V
  • We calculate the useful energy of the power bank to use the laptop and recharge its battery:
    • Useful energy = Power bank energy x 0.7225 = 72Wh x 0.7225 = 52Wh

Time of use with the chosen tasks:

  • Laptop battery removed:
    • Theoretical data: Useful energy Power bank / Average laptop power consumption = 52 Wh / 25.5 W = 2h
    • Actual data: 2h 50min
  • Using the laptop and recharging its battery at the same time:
    • Actual data:
      • Laptop usage time with power bank: 1h 41min + 35% of the battery recharged.
      • Total usage time: 2h 33min
Acer Aspire E5

Laptop:

  • Model: Acer Aspire E5-551-T2HE
  • Charger: 19V/3.42A (65 W)
  • Charging voltage: 19V
  • Battery energy: 56Wh (5000mAh/11.1V) reduced to 45Wh
  • Charging port: DC Lenovo (square jack)
  • Usual usage tasks: office automation and web surfing
    • Battery life 100%: 3.5h
    • Average laptop consumption: 45Wh /3.5 h = 12.9W

Power bank:

  • Model: Litionite Vulcan 20000mAh USB-C PD 65W
  • Battery capacity: [email protected] 74Wh
  • USB-C PD port: 5-20V (65W max)
  • Charging voltages: 5-20V (read this)
  • Cable: USB-C PD to DC jack 5.5×2.1 20V
  • Adapter: DC jack 5.5×2.1 to DC jack 5.5×1.7
  • We calculate the useful energy of the power bank to use the laptop and recharge its battery:
    • Useful energy = Power bank energy x 0.7225 = 74 Wh x 0.7225 = 53.5Wh

Time of use with the chosen tasks:

  • Laptop battery removed:
    • Theoretical data: Useful energy Power bank / Average laptop power consumption = 53.5 Wh / 12.9 W = 4.15h (4h 9min)
    • Actual data: 4h 37min
  • Recharging battery with laptop off:
    • Theoretical data:
      • Number of charges = Usable energy / Laptop battery energy = 53.5Wh/45Wh =1.19 charges.
      • Usage time = No. of charges x Laptop battery energy (Wh) / Laptop power consumption (W) = 1.19 x 45 Wh / 12.9 W = 4.15 h (4h 9min)
    • Actual data:
      • Number of charges = 1.42 charges
      • Usage time = 4.95 h (4h 57min)
  • Using the laptop and recharging its battery at the same time:
    • Actual data:
      • Laptop usage time with power bank: 1h 50min + 82% of the battery recharged.
      • Total usage time: 4h 41min
HP Stream 11

Laptop:

  • Model: HP Stream 11 (11-d010nr)
  • Charger: 19.5V/2.31A (45W)
  • Charging voltage: 19.5V
  • Battery energy: 37 Wh
  • Charging port: DC HP 4.5/3.0 mm (blue round jack)
  • Usual usage tasks: watch Netflix with maximum brightness on HD resolution screen (720p).
    • Battery life 100%: 6h 29min = 6,48h
    • Average laptop consumption: 37Wh /6.48 h = 5.71W

Power bank:

  • Model: Baseus 20000mAh USB-C PD 45W
  • Battery capacity: [email protected] (76Wh)
  • USB-C PD port: 5V/3A, 9V/3A, 12V/3A, 15V/3A, 20V/2,25A (45W max)
  • Charging voltages: 5V, 9V, 12V, 15, and 20V (read this)
  • Cable: USB-C PD a DC HP 20V
  • We calculate the useful energy of the power bank to use the laptop and recharge its battery:
    • Useful energy = Power bank energy x 0.7225 = 76 Wh x 0.7225 = 54.91 Wh

Time of use with the chosen tasks:

  • Recharging battery with laptop off:
    • Theoretical data:
      • Number of charges = Usable energy / Laptop battery energy = 54.91 Wh/37 Wh =1.5 charges.
      • Usage time = No. of charges x Laptop battery energy (Wh) / Laptop power consumption (W) = 1.5 x 37 Wh / 5.71 W = 9.72 h (9h 43min)
    • Actual data:
      • Number of charges = 1.75 charges
      • Usage time = 8.98h (8h 58min)
  • Using the laptop and recharging its battery at the same time:
    • Actual data:
      • Laptop usage time with power bank: 1h 45min + 85% of the battery recharged.
      • Total usage time: 8h 15min

Best power banks for laptops (October 2023) 🚩

Once you are familiar with the features of a laptop power bank, we present the best models available on the market taking into account the different types of output ports: DC, AC, and USB-C PD.

Notice: Remember that if your laptop has a DC charging port and you choose to buy a power bank with a USB-C PD port you need to use a USB-C PD to DC adapter.

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Wilfried

I am a fulltime bicycletraveller since 2018. My tip is to choose a laptoppowerbank with a DC-output. Those come with a separate wallcharger that has a dc-out voltage that you can also use directly to power your laptop, so without the powerbank inbetween. You will need a dedicated adapter for your laptop but they are for sale for little money and also come with most universal powerbanks and with laptopsolarpanels. In other words, you will have the powerbank plus an extra wallcharger. However, I have been using laptoppowerbanks for some 10+ years but stopped using them. They are quite expensive… Read more »