Now that I can shoot 600 film, I'd like to be able to use i-Type film. It's the same film as 600 but has no battery in the pack.
That means the SX-70 needs another power source. There's a few solutions out there. I prefer something that's not permanent/easily reversible and one I can make myself.
Here's my attempt. It's a replacement bottom shell with 18650 and charge/boost.
I modified an existing shell design to accommodate the battery. Bonus is the neck strap mounting points (something sorely missing from the 1st gen).
Buuuut, it doesn't work. The LX-LCBST charge/boost circuit shuts down as soon as the motor is connected. The boost out is rated at 1A but I'm guessing the motor pulls too much as it starts. Boo.
Second attempt at a i-Type battery mod for the SX-70. I call it "The Barnacle" because it snaps onto the bottom of the camera and uses pogo pins to inject power.
There's also a 1/4" tripod mount snap on as well.
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.
@paulrickards I mean… it’s probably not still too late to just pop an ND filter over the lens, and that way you can use either pack.
@octothorpe The ND filter isn't needed now that the capacitor has been changed.The missing battery from i-Type film packs that is the road block.
I'll probably iterate some more until I find a circuit that can tolerate powering the motor.
Jul 29, 2026, 5:24 PM@paulrickards whoa. That is really cool with an interesting result. Idve said 18650 as well. I wonder what the solution is.
@paulrickards in my experience step up can be somewhat temperamental. It may even not be a problem of the motor drawing too much current.
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 🙃
@paulrickards But this is *a lot* more elegant than the barnacle! Wouldn't it be possible to combine the two attempts: Replacement bottom shell with the battery shield?
@PistonPin It is really nice but unfortunately the battery shield is too big and doesn’t fit inside the case. I need to find a different, smaller, boost circuit that works and fits inside the case.
The only draw back to this approach is it’s not quickly removable like the barnacle.
@paulrickards I see. Hmm… Would designing an additional outer “shell” that fits over the actual bottom/cover be doable?
@paulrickards Impossible's reason for having only 8 photos per pack was always "The new battery is thicker, we can only fit 8" (I tried and managed to easily fit in 10 undeveloped photos in an Impossible pack). But now with the I-Type, there's no more excuse for that, but still only 8 photos. Mildly infuriating.