How to Build Your Own 7.2V Dremel Battery Pack

Written by mary lougee
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Dremel tools are highly versatile tools that perform many tasks like drilling, cutting, sanding and polishing. Their small size allows you to work on around-the-house projects with ease, but eventually a 7.2-volt battery pack will not hold a complete charge. You can build your own replacement battery pack at a much lower cost than purchasing a new one.

Skill level:
Moderately Easy

Things you need

  • Soldering iron with chisel tip
  • Paper and pen
  • 6 AA rechargeable lithium ion batteries
  • Solder
  • Epoxy glue
  • Paper plate
  • Cotton swab

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  1. 1

    Plug the power cord of a soldering iron into an electrical receptacle. Let the light illuminate to show it is hot and press a chisel tip on the nose.

  2. 2

    Place the old Dremel battery pack on a table or flat surface. Press the chisel tip on one side of the battery pack near the top edge. Squeeze the soldering gun trigger to apply heat and melt the battery pack. Move the chisel tip horizontally as the plastic melts to circle the entire battery and melt the top loose. Pull the battery pack top straight off. This reveals 6 AA batteries inside the pack.

  3. 3

    Draw a diagram on paper with a pen of the wiring on the 6 batteries and their positions. Draw each battery and note the negative and positive terminals.

  4. 4

    Pull the chisel tip off the soldering gun. Place the tip of the soldering gun on each wire end that connects the batteries and squeeze the trigger. This action desolders the connections. Pull each wire off the batteries. Pull the old batteries out of the pack.

  5. 5

    Place the 6 AA rechargeable lithium ion batteries in the pack. Refer to the diagram for placing the batteries in the pack and the wiring diagram.

  6. 6

    Place one end of a wire on a battery. Hold a stick of solder in one hand and squeeze the soldering gun trigger with the other to apply heat to the solder. Melt one to two drops of solder on the end of the wire to adhere it to the battery. Repeat process to attach all wires to the battery as shown in your diagram.

  7. 7

    Replace the top on the battery pack. Mix equal parts of epoxy adhesive together on a paper plate. Apply the epoxy along the horizontal line of the battery pack that you cut to open it with a cotton swab. Let the epoxy dry according to the package instructions before placing the battery pack in the Dremel.

Tips and warnings

  • Charge the new battery pack on a charger before using it.
  • Lithium ion batteries contain 1.2 volts each, so when they are wired in a series of 6, the combined voltage is 7.2 volts.
  • Electronic stores sell rechargeable AA lithium ion batteries.

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