Welch Allyn 71052 & 70752 Handle Battery Adapters

71052 Adapter - Emulates a Welch Allyn 72200 Battery

70752 Adapter - Emulates a Welch Allyn 72000 battery

The goal of the design was to use a minimum amount of materials and tools to assemble. These adapters were created for a quick demonstration which they worked successfully for; though I'm unsure of the longevity especially if reinserted multiple times. Hopefully somebody else will find these adapters useful.

If using this adapter do not use the charging prongs of the handle, this will very likely result in you having a bad day.

Parts Needed:

71052:

1. 2x 10mmx18mm Springs
2. 3x AAA Round Battery Holder
3. 1x 1ohm Resistor 
4. 3x Rechargeable (1.2v)AAA Batteries

70752:

1. 2x 10mmx18mm Springs
2. 2x AAA Battery Holder
3. Electrical Tape
4. 2x Rechargeable (1.2v)AAA Batteries

Assembly:

71052:

1. Print both parts of the ‘71052 - Adapter’ model.
2. Take the print with the larger hole and insert one of the springs halfway through.
3. Wrap one of the legs of the resistor around the end of the other spring.
4. Place the resistor in the hole of the smaller print so that the spring sits in the recessed part.
5. Flip the part over and bend the resistor leg over a few times so that it is mainly central.
6. Place the batter holder between the two prints with the negative side of the holder touching the bent resistor leg.
7. Slide the adapter into the base with the shorter spring first.
8. Before screwing on the cap remove the spring if it's present.

The assembled adapter should look something like this:

70752:

1. Print the ‘70752 Adapter’ twice.
2. Place a small amount of electrical tape over the two ends of the battery holder, making sure to completely cover the contacts.
3. Take one of the wires and pass it through the hole of the printed part.
4. Wrap the exposed wire around the bottom of one the springs.
5. Then push the spring into the hole of the printed part. This should look similar to this:
   • 
6. Repeat steps 3-5 for the other wire.
7. Place the two parts on the ends of the battery holder.
8. Secure any loose wire to the back of the battery holder.
9. Slide the adapter into the holder with the positive (red wire) side first.
10. Before screwing on the cap remove the spring if it's present.

The assembled adapter should look something like this: