One of the more popular posts on this blog explains how to prevent the button cells in the SQ-Ai from slipping away from the camera contact, using nothing more than a piece of cardboard. This still leaves a problem for those who are missing the battery holder altogether.
About the only alternative to an expensive motor-grip or external pack is a 3D printed replacement holder. Luckily, there is a design freely available. This of course leaves open the question of how to design the electric contacts. I have never tried this, so the best I can do is produce some more detailed photographs. Let’s start with a view of the contact side of the battery holder with a basic scale.
This side shows the contacts of the battery holder: the holes in the middle provide access to the minus pole (the electrically isolated disc in the centre of a button cell). The square metal plates visible at the bottom of the holder connect to the plus pole (the main body of the button cell). To see this more clearly here is a closer view with a high contrast background.
The metal plates for the positive contact are in fact folded over from a metal part screwed into the side of the battery holder. We can see this by flipping the battery holder over:
At the bottom we see where the contact plates in Picture 2 are folded over. The metal part itself is secured with two mounting screws (or bolts, it doesn’t look like they can be removed in the original part). To the side of either screw, there is another metal protrusion folded into the interior of the plastic battery holder:
Picture 4 shows the inside of the battery holder. This is the hardest part to photograph, but it shows how the folded in contacts form a kind of pincer which holds the (positive) outer body of the button cell. Making this metal contact may be fiddly. The metal parts in question are the only electricity conductors in the battery holder.
The top part, to which the positive pole of the button cell points, is just plastic. This is where the cardboard shims are placed in the original ‘battery problem’ blog post.
Using a borescope to photograph the metal plates visible in Picture 1 shows them to be thinner than a business card ( shown bent upwards). The cardboard of the business card is measured to have a thickness of 0.3mm using sliding calipers.