The SQ-Ai Battery Holder and its Contacts

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.

Picture 1

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.

Picture 2

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:

Picture 3

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

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.

Picture 5

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.

Update:

The thickness of the metal contacts is difficult to judge. No protrusion is visible when looking at the square contacts in picture 2, but the metal plates can be felt above the plastic surface.

 

 

 

 

 

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.

7 Replies to “The SQ-Ai Battery Holder and its Contacts”

  1. Boris,

    That is a great help to me. Thank you.
    I’ll be printing two of the plastic holders tomorrow.
    All I need to do now is figure out those contacts. These pic’s are a really good start.

    I’ll let you know how I do next week.

    Thanks again.
    Steve

  2. Boris and others,
    I was able to use the free printer file and had a battery holder 3D printed. Cost was $25US and 1-day turn around.

    The holder fits into the SQ-Ai perfectly.

    I’m still figuring out the connectors. I’ve bought copper foil tape and used that to connect the (+) side of the battery to the contact side of the holder.

    If I use my dvm to check voltage from the (-) side of the battery to the foil wrap I can get the 1.5V. However, once I install the holder into the camera, it does not work. I think the foil is too thin to contact the pins in the camera.

    My next attempt will be to stack 4 or 5 layers of the Cu foil. If possible can you get me an estimate of the thickness is of those metal connectors. (How many mm thick is the metal?)

    Boris, if there is a way for me to post images I will show all how I am working this project.

    Steve

      1. Thanks Boris,

        At this point, I think my Cu foil contacts are good and my camera might be bad.
        Later today I will perform one more test using 4 external 1.5V batteries in external holders. I’ll connect to the pins using alligator clips. If that does not work, the camera is bad. I can return the camera for a full refund. So no loss on my part.

        I’ll just shoot my SQ-B.

        Steve

  3. Here is the last update on my recently acquired SQ-Ai from Japan.
    It arrived without a battery holder, the seller offered a 50% discount to cover the hassle to 3D print one. I accepted.

    Once I printed a holder the camera did not work. Upon closer inspection it was clear that battery leakage had been an issue and not disclosed. I informed the seller I was wanting a total refund. He agreed, however, told me to keep the camera. So I had a non-working SQ-Ai for free. Plus I spent $50 to 3D-print two holders.

    I was very lucky to find a repair shop in southern CA who knew the Bronica line and was able to repair the camera for $150US.

    I now have a near mint Ai that is working perfectly.

  4. I made the metal part according to the original battery holder measurement, and used 0.3mm copper plate cutting and processing. It works very well with the 3D printed battery holder. If necessary, I can share the measured size drawing, hedan246@gmail.com

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