The Benefits of Owning a Portable Laptop Battery Pack

Owning a decent laptop is beneficial when it comes to productively spending your time on-the-go, whether you're working on gaming or watching your favorite web video creator. However, the limited runtime of the laptop's built-in battery pack can be a major drawback.

To charge up and extend the laptop's runtime, many people consider creating a portable battery pack using a laptop power supply. This project requires careful planning and execution to ensure safety features are included. In this article, we'll explore how to create a portable laptop battery pack with all the necessary voltage levels and safety features.

Collecting Data on Laptop Battery Pack Specifications

Before starting the project, it's essential to collect data on the laptop's battery pack specifications. The built-in battery pack of my laptop states a voltage rating of 11.1V DC and a capacity of 4400mAh. This translates to an energy of around 49 Wh.

The laptop itself states an input voltage of 19.5V with a maximum current draw of 6.15A, which also corresponds to the ratings of the laptop power supply. To test this, I plugged in at 5.5 by 2.5 mm DC jack into the laptop and connected it to my multimeter.

Understanding the Importance of Safety Features

When creating a portable battery pack, safety features are crucial to ensure the protection of both the user and the device. The buck converter that will be used as part of the project must have a constant current and voltage mode to prevent overcharging or undercharging the battery.

Additionally, it's essential to include an LED voltage tester to monitor the voltage of each cell in the battery pack. This allows for easy detection of any issues or imbalances in the cells.

Designing the Battery Pack Enclosure

Once all the necessary components have been selected and tested, it's time to design the enclosure for the portable laptop battery pack. The enclosure should be sturdy enough to protect the internal components from damage while still allowing for easy access.

In this project, I created a suitable enclosure using 3D modeling software and then 3D printing the parts. After completing the 22-hour printing session, I combined the two parts of the enclosure with a bit of glue and added additional features such as switches and DC jacks.

Assembling the Portable Laptop Battery Pack

With all the components ready, it's time to assemble the portable laptop battery pack. The first step is to connect the boost converter to the laptop power supply and set its output voltage to 33.6V, which is eight times the recommended charging voltage.

Next, I connected the constant current potentiometer to its minimum value and hooked up the boost converter's output to the battery pack in series with my multimeter. This allowed me to adjust the constant current limit to 2.5A, which is two times the recommended charging current of one cell since we have two cells in parallel.

Wiring the Portable Laptop Battery Pack

After assembling all the components, it's time to wire them together. The wiring scheme was challenging, but with careful planning and patience, I was able to create a reliable connection between the buck converter, switches, DC jacks, and boost converter.

Adding a Final Touch: Testing the Portable Laptop Battery Pack

The final step is to test the portable laptop battery pack to ensure it's working as intended. I connected the battery pack to my laptop and observed its performance under various conditions.

The results were impressive – the portable laptop battery pack charged my laptop seamlessly, even with high amp values, without generating any voltage spikes that could harm the laptop circuitry.

Conclusion

In conclusion, creating a portable laptop battery pack is a challenging project that requires careful planning, execution, and attention to safety features. However, with the right components and design, it's possible to create a reliable and efficient solution for extending your laptop's runtime on-the-go.

WEBVTTKind: captionsLanguage: enOwning a decent laptop is beneficial when it comes to productively spending your time on-the-goBy for example working gaming or watching your favorite web video creatorThe only problem is the limited runtime of the laptop's built-in battery packwhich normally get charged up through the included laptop power supplywhich is fueled by main voltageso to charge slash power the laptop on-the-goI got the idea of creating a portable battery packwhich we can charge up fully laptop power supplyand later use it to give the laptopand additional runtime of around three hoursThe process of creating such laptop power bank with all the required voltage levels and safety featureswas not that simple thoughSo sit back and enjoy my take on creating such a portable laptop battery packLet's get startedThis video is sponsored by JLC PCBsthe most popular PCB prototype company in Chinawhich produces more than four hundred thousand square meters of PCBs per monthSo upload your gerber file today to try out their PCB service for only two dollarsTo start off I had to collect some dataThe built-in battery pack of my laptopstated a voltage rating of 11.1V DCand a capacity of 4400mAhSo an energy of around 49 WhThe laptop itself states an input voltage of 19.5Vwith a maximum current draw of 6.15Awhich also correlates with the ratings of the laptop power supplyTo test this I plugged in at 5.5 by 2.5 mm DC jackinto the laptop and connected it to a lab bench power supplyset to 19.5 V DCand sure enough the laptops battery pack started chargingand while simultaneously running a benchmarkit drew a maximum of close to 5ASo 19.5V and a maximum of 6.15Ashould be the output characteristic of our laptop power bank.what is also important safety wise is how much the supply voltage fully laptop can varyNow since I did not feel like frying my laptop with overvoltageI rather disconnected the powerand started removing a few dozens of screws in order to find out how the DC Jack voltageis connected to the PCB ICsBut even after removing the SSD as well as the cooling systemI was not able to get to the DC Jack.What I was able to figure out though was that the input voltage is directly connected to this connectorwhose closest IC were this BQ737and this TPS51211The BQ737 is a one to four cell lithium battery charge controllerwhich is obviously used to charge up the three s lithium ion laptop battery packThe IC features a maximum recommended voltage of 24Vwhich gives us some space to play around.But we should keep in mind that the datasheet also statesthat a voltage spike beyond the VCC voltagecan destroy the ICNow the other I see here known as the TPS51211is a stepdown controller for notebookswhich creates a small voltage for the laptop componentsWhat a coincidence.This one even offers an input voltage of up to 28Vso even more space to make mistakeswith this knowledge we basically learn that 19.5V would be greatbut does not have to be spot on.Just like the power supply of the laptopdoes not exactly delivered this valueSo after reassembling my laptopwhich was only a bit tediousI tested whether it still work correctlywhich it didand grabbed my E-bike battery pack from a previous video.It consists of 13 lithium ion cells in serieswith two cells in parallel each.but feel free to watch the video about itin order to find out its specifications.How I built itand why I do not use it for my E-bike anymoreand thus can repurpose it for those projectsThe only problem is that thirteen cells in seriesis not only a bit too bigbut also comes with quite a high voltageas a solution I desoldered the thick positive and negative battery wiresas well as all the balance wiresand cut the battery pack at the eight cell series connectionThis way my new pack got the maximum voltage of 33.6Va nominal voltage of 28.8Vand a minimum voltage of 20Vat 2.5V per cellAlso the pack can continuously deliver 40Aand features a capacity of 5Ahwhich equals a nominal energy of 144WhThus by assuming a conversion efficiency of 70%we should be able to charge up the laptop battery pack up to two timeswhich should give us three more hours of laptop runtimeAwesome!The next component for the power bank is this BMS circuitalso known as battery management systemThis circuit adds an over current overcharge and over discharge protection to the battery packas well as a cell balancing featurewhich is pretty much mandatory for multi cell battery packs.So after soldering its included balance wires to the battery packas well as new power wiresand plugging in the connectorWe gott our predicted output voltagewhich is mandatory for the next componentsa powerful buck converter that can output up to 8AAfter hooking it up and flipping its power switchI adjusted its output voltage to 19.5Vand set its current limit to the highest valueThrough a DC terminal I then connected this output voltage to the laptopwhich as you can see charging laptops integrated battery just fineEven higher amp values are no problem for the set-upwhose heat sink stayed pretty cool during all the testsand most importantly during switching on or off the buck converterit did not create any kind of voltage spikeswhich would be harmful for the laptop circuitryNext in order to check when the power bank is completely dryI also added a LED voltage tester to the battery packfor which I desoldered its buzzershooked up a second pair of eight balance wiresand connected them all to a male headerto easily connect them to the LED power voltage tester.Now we can see the voltage of each celland basically disconnect the battery at a cell voltage of 3VLast but not least we need to charge up the batteryfor which I got myself this powerful boost converterwhich can output up to 60V and 12AIt is important though that it also features a constant current constant voltage modeTo use it I firstly connected the output of the laptop power supplyto the input of the boost converterand set its output voltage to 33.6Vwhich is eight times the recommended charging voltage or 4.2VAfter then turning the constant current potentiometer to its minimum valueand hooking up the boost converters output to the battery packIn series to my multimeter in current measuring modeI then adjusted the constant current limit to 2.5Awhich is two times the recommended charging current of one cellsince we got two of them in parallelAnd as you can see by observing the rising voltage of the battery packas well as the constant currentwe are charging the battery properly with the CCCV charging methodto later easily check this charging processI also added a voltage / current monitor circuit to the output side of the boost converter.and after doing a couple of tests this setup seems to work surprisingly wellSo I created a suitable enclosure for the new battery packas well as all the complementary componentsin one 3D designand 3D printed it afterwards.Once the 22 hour printing session was completeI combined the two parts of the enclosure and the lids with a bit of glueand moved on by mounting the switches and DC jacksand since I messed up when measuring the height of the LED voltage testerI had to shorten its PCB a bitbefore I could glue it into positionAfterwards I used hot glue to secure the battery pack inside the enclosuredid some cable managementsand moved on by wiring all the DC jacks switches and buck converters to one anotherOf course explaining the wiring through words can be pretty confusingso if you plan to build something similaryou can find a wiring scheme for these projectas well as pictures and additional informationAs always in the video description.Now as soon as I secured the boost and buck converter to the enclosure with M3 screwsI added the lid to the projectcreated a connection wire for my laptopand did a final test by charging up the laptop power bankand afterwards using it to power my laptopwhich both worked flawlesslyand with that being said I declare this project a successand I hope that you enjoyed watching this videoIf so don't forget to Like Share and SubscribeStay creativeand I will see you next time.