Inside is a "18650 battery shield" board that provides charge/boost to 5V (with an added 10uF cap). It also does 3.3V but not using it.
Even though the camera usually uses 6V, it seems to work OK with 5V.
Power is delivered underneath through two small pogo pins.
This idea came from the "remora" case by nunocruz which is honestly a lot smaller than my solution but I have so many 18650 batteries to use.
Looks like someone else tried to make an all in one SX-70 battery mod bottom shell but ran into the same boost issues I did.
https://www.reddit.com/r/Polaroid/comments/1t1ee8b/sx70_battery_mod_help/
Revised the design a little for The Barnacle battery for the SX-70 to be smaller and rounded at the bottom saving some space. Also some legends for attaching it and cut outs for the LEDs.
The board is cool because it has both micro USB and USB-C inputs for charging plus USB-A outputs to power something else.
Being underneath, it points the camera up instead of down so shots on a table with a timer are framed better.
Aug 2, 2026, 6:45 PM@paulrickards No idea if this relates. But I recently saw a video that talked about the SX-70 and I think they mentioned the motor pulls 2 (or 3!) amps when ejecting. (also you probably already know that)
@h5e Thanks for that! These are new numbers for me. I've not found a definitive value for how many amps it draws. I wouldn't be surprised if it peaks at 3A though.
Aug 3, 2026, 6:37 AM@paulrickards ok I’ll try and find the vid later! I imagine pulling that amount of juice through a lower power boost circuit can cause weird effects.
Aug 3, 2026, 11:07 AM@paulrickards Here it is!
@paulrickards Wow! All this from a little resistor swap ;-)
Very cool!
@octothorpe Thanks! I'm all iterate, iterate, iterate 🙂
Aug 4, 2026, 9:29 PM@paulrickards This looks fantastic, Paul.If the height of the case is still changeable, it might be cool to have the lens be perfectly horizontal when at rest, but if the camera model has a screw-in tripod feature, that'd be immaterial.
Very impressive.
@Luke Thanks! No camera tripod mount on this model but I did print a tripod mount snap on for the camera.
Aug 4, 2026, 10:01 PM@paulrickards Oh, that's perfect!
(also: love that this thread exists, well done)
@Luke Thanks! I'm glad you enjoy it. I always hope that my tinkering can help someone else someday.
I'm also likely not done tinkering with it yet 🙃