How to Build Power Bank Using Old Laptop Battery - Step By Step Guideline

We all use laptops for our daily tasks and tend to replace the laptop batteries when battery is not capable enough to hold the charge despite charging for several hours. However, a little hack will help to use the good batteries in the removed battery pack for making a power bank. You can save your hard earned money and use the power bank for charging a mobile phone and other applications.

The usual life of a battery pack is around 3 years. If you are not overcharging the battery pack and taking proper care, you can easily extend its life. Two cells are connected in parallel and the resulting 3 sets are serially connected in a 6 cell battery pack. The lithium cells connected in such an arrangement provide the desired voltage to operate your laptop while on the move.

Some of the notebooks usually consist of 4 cells in a battery pack. However, laptops are usually fitted with a 6 cell battery pack. The laptop or notebook has an intelligent circuit to indicate health of the battery pack. The program in Windows detects the signals from the battery pack and updates about the health of the battery pack. The intelligent circuit in the battery pack disconnects the output voltage to the laptop even if a single battery voltage is low. As a result, the battery pack life is over. When its life is over and no longer usable, the Windows OS indicates you to replace the battery immediately.

In most of the battery packs with 4 cells, one cell usually gets exhausted and making it unsuitable for your use. You will not get the back up from this battery pack. You are forced to change the battery pack to make your notebook portable.

Don’t throw your laptop or netbook battery pack. They can be salvaged to build a power bank to power various electronic devices. You can even repair and reuse the battery pack by replacing the defective batteries. If you are one of the guys who wants to make use of such dead battery packs, this article is for you. This article focuses on building a powerbank using the good cells from the dead battery pack. Read on to know about how to create a power bank using the removed battery pack of a laptop.

Some of the batteries in the battery pack are usually good. The battery pack has a protection circuit that disconnects the laptop if one or two cells are dead. So, you can utilize the good cells to make a power bank using the following steps. However, you should be careful in performing the following tasks to prevent health hazards.

Items required for making Power Bank

  • Digital Multimeter
  • Flat Screw Driver
  • Soldering Iron
  • Solder
  • USB connector
  • Wire Cutter
  • Hand Gloves
  • Thin wires
  • Power bank Case
  • OTG Cable

Procedure to Make a Power bank

  • You need to wear the hand gloves before attempting this circuit. You can make use of the flat screwdriver to open the battery pack on the other side of the connector (of the battery pack). You should be careful to not cause any damage to the cells in the battery pack during the extracting process.
  • The battery pack usually consists of 6 cells. You can extract the cells and the protection circuit from the battery pack.
  • Now remove the tapes and connections from the six cells and separate each cell. The multimeter has red and black wires. You need to keep the mutlimeter in DC voltage mode to measure the voltage of the cells. You need to connect the red wire to the bulging point of the cell and black wire to the flat terminal. Test the voltage of each cell and select the good cells having voltage above 3V.reuse-your-old-laptop-battery-to-make-power-bank-step1reuse-your-old-laptop-battery-to-make-power-bank-step2
  • You need a power bank case, which you can easily get from an electronic store. Otherwise, you can make use of a rectangular plastic box for the power bank.
  • The power bank case consists of battery holder, USB ports, and built in charger. The charger circuit has LED indicator and overcharging protection. The blue indication of the LEDs tells you that batteries are fully charged where as the red color indicate that batteries are being charged. It doesn’t have reverse polarity protection. So, you should be careful to connect red terminal to the positive and black to the negative. OTG cable is necessary to provide power to the batteries for charging.
  • You need to connect the batteries as per the following circuit.reuse-your-old-laptop-battery-to-make-power-bank-step3
  • The batteries are connected in parallel to increase the capacity. The batteries in series connection increase the voltage. Therefore, the parallel and series connection is employed to achieve desire capacity and desired voltage for charging the mobile. In this connection, if you have used 3 batteries each of 3V, you will get a total voltage of 9V. Similarly, if each battery has 3000 mAH when connecting 2 batteries in parallel, the charge of each pair increases to 6000 mAH. In this connection the total capacity of the batteries is 18000 mAH.reuse-your-old-laptop-battery-to-make-power-bank-step4
  • B+ and B- terminals of the charging circuit are to be connected to the batteries positive and negative terminal as per the above circuit.
  • Connect the Red wire and Black wire of the OTG cable to the mobile.
  • You can make use of the soldering iron for making these connections permanent.
  • You need to properly fix the battery pack in the power bank case and charge it fully. It will take around 2 hours to fully charge the battery pack.
  • Now, you can disconnect the battery pack from the charger. You can use the battery pack to charge any mobile.
  • Therefore, you can make a power bank using old battery pack and save your hard earned money.
  • If you do not have expertise to fix and solder the batteries and the power bank as above, you can seek the help of a trained technician.reuse-your-old-laptop-battery-to-make-power-bank-step5

Wanda Greaves is the co-founder of – a website that helps people to find, use and do anything with their batteries, chargers or related electricity devices. Check out their latest article about choosing the Portable Jump Starter.