Monday 28 March 2011

How to Build an External Notebook Battery

How to Build an External Notebook Batterythumbnail
Wire batteries in series to build an external notebook battery pack.
Notebook batteries average about 500 charges and discharges before they go dead. If you account for a full charge lasting between one and three hours, depending on the applications you are running, it's easy to see that your battery is likely to die before you need to replace your notebook. The problem is that replacement batteries can cost over one-third the price of a new notebook. However, building an external notebook battery using lithium polymer, or LiPo, batteries is a much cheaper alternative and can be done in a couple of hours.

Difficulty:
Challenging

Instructions

things you'll need:

  • LiPo batteries
  • Power jack
  • Wire (AWG 16 gauge)
  • Electrical insulating tape
  • Small knife
  • Wire strippers
  • Soldering iron
  • Solder
    • 1
      Look on the bottom of your notebook to find the input voltage requirement. It's likely to be in the range of 14.8 to 19 volts. The input voltage determines the number of LiPo batteries you need to build your external notebook battery pack. Each LiPo battery produces 3.7 volts so you need four or five batteries, depending on the voltage requirement, wired in series. Wiring in series combines the voltage from each battery so four LiPo batteries produce 14.8 volts and five 18.5 volts.
    • 2
      Put your LiPo batteries on a flat surface. LiPo batteries are similar in design and size as regular AA batteries. They have a positive terminal on the top and a negative terminal on the bottom. Alternate the battery terminals. Using four batteries you have positive, negative, positive, negative facing one way and negative, positive, negative, positive facing the other way.
    • 3
      Label the batteries numerically, either 1 through 4 or 1 through 5. Wrap the batteries in electrical insulating tape so you form a battery pack.
    • 4
      Cut strips of AWG 16 wire using a small knife. AWG 16 is suitable to carry the volts the battery pack produces. Cut two wire strips about 12 inches long so they can reach between your notebook and battery pack. The other wire strips need to be short: about 1 1/2 inches long, as they only need to connect between the battery terminals in the pack. The number of short strips depends on the number of batteries in your pack. A simple way to calculate the number of short strips is to count the number of batteries you are using, then deduct one. For example, if you're using four batteries in your pack, you need three short strips, and if you're using five batteries, you need four short strips.
    • 5
      Label the two long wires "+" and "-" respectively. Remove ¼ inch of plastic coating from the ends of every wire using wire strippers or a small knife to expose the copper wire.
    • 6
      Attach the long wire labeled "+" to the positive terminal of battery 1 and then attach the other long wire strip to the negative terminal of the last numbered battery in your pack. Use electrical insulating tape to attach them.
    • 7
      Attach a short wire strip to the negative terminal of battery 1 and the opposite end of the strip to the positive terminal of battery 2. Repeat attaching the short wire strips to the negative and then positive terminals of the remaining batteries in numerical order. The last short wire strip connects to the positive terminal of your last numbered battery.
    • 8
      Wrap the entire battery pack in electrical insulating tape. Make sure the two long wires extend from the pack, as you need to connect them to your notebook. The other short wires connecting the battery terminals need to be covered in tape.
    • 9
      Heat the soldering iron to operating temperature. Meanwhile remove the cover from your power jack. The power jack must be the same size as the power input socket on your notebook. Slide the cover over the two long wires.
    • 10
      Place the "+" labeled wire on the positive terminal of the power jack, then introduce the solder and soldering iron. Let a little solder melt so it coats the wire and terminal. Remove the soldering iron and let the solder cool, then fuse the wire and terminal together. Repeat the process using the "-" labeled wire attaching it to the negative terminal of the power jack. Allow the power jack to cool. Turn off the soldering iron.
    • 11
      Slide the power jack cover down the wires and screw onto the jack. Insert the jack into the corresponding input socket on your notebook. You have built an external notebook battery.

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