I was tasked with getting two Welch Allyn Handles (71052 & 70752) working for use in a demonstration. The only problem was that the batteries supplied had a 'guaranteed to' date of October 1986 printed on them. Not wanting to take a risk with batteries that were 30+ years old and with the high cost of buying new replacement batteries, I set off to create a 3D printed adapter that used a minimum amount of materials / tools to assemble.
Through a few revisions I was able to create a 3D printed adapter that accepted rechargeable (1.2v) AAA batteries for both of the batteries types (72200 & 72000). The design does come with two notable drawbacks compared to using an official battery, reduced capacity and the inability to use the inbuilt charging. But overall its still very usable, especially if you have no suitable alternatives.