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Forum: Pentax Medium Format
05-10-2021, 12:43 AM
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Power to the 645 - part three
I decided to make a 3D printed battery insert. I'm not a CAD wizard, but I made a copy of the bottom plate and a battery compartiment on top. To make it sturdier, I went for a single 9V block design and thicker walls. somehow the 'chamber was too high when printed, so I cut of a part. In this prototype I did some filing to make it enter smoothly, and to reduce the bolts that form the contacts. WARNING - it should fit snugly, but don't force it in or you'll break the tabs inside the grip !!!!
For now I joined the two parts with a piece of wood and two small screws, one day I'll make a finished insert.
As for the power source, I took a special 9V rechargeable Li-ion block, boasting 780 mAh against your average 200mAh batt, that should do the trick for quite some rolls. Anyone who wants to use these 'draft' 3D files,I'll make them available. If you follow the Pentax 645 facebook group, a pro member has jumped on the 3d-printed inserts too :) :) :)
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Forum: Pentax Medium Format
03-16-2021, 11:37 AM
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Hello,
having two 645 bodies and one working battery holder I started looking for solutions myself, here's a copy of my advancements (facebook pentax 645 group)
Power to the 645 - part one
I do like the original Pentax 645 camera, and up to this moment I never minded manual focus or having the less performant metering system compared to the 645N(ii). I manage 
Main perks : the diopter adjustement's drifting away ( I improvised a cap from a water bottle I put over the eyepiece to prevent it from being pushed inwards in my bag), and the camera's Achilles' heel : the battery pack. Over time many of these have cracked under the pressure of the spring in the grip, and they have become far more rare and expensive than the camera body itself.
Part one : repairing a cracked one
I got my hand on a cracked battery pack, and decided to reinforce it :
No use just gluing the backside cracks, they wont stand long against the pressure, so I reinforced with a thin sheet of metal (sodacans everywhere..) and contact glue (flexible). Important : roughen up the surfaces, otherwise the plastified metal won't stick. seems to work ... but now I notice there's a plastic retainer triangle missing on the bottom ... (§è§!!###é@!!!!!)
Maybe replace it by a metal one ? but how..
Power to the 645 -
Part two : the grip's external power socket
An external power pack exist, you screw the connector cable into the grip to keep the batteries warm in your pocket when cold. Alas, it uses the same battery pack ..
Easiest solution would be buying the thing, cutting the cable and attaching it to a 6xAA pack you can easily make, buy or print. Okay, but they are rare and again bloody expensive for a stupid cable&connector. So why not make a connector .. the screw thread is seems to be M10, you just need an internally threaded tube narrow enough to go into the connector's recess. Just a good look in the hardware store .. Got it ! Or take an abs rod, bore and thread it.
Time to make a 3D drawing of the connector body..
As for the holder : I started a 3d model too.. just the beginning, still some scaling to do.. I think of making a dummy with a connector to a power pack .. or the real thing if I can reinforce it ..
---------- Post added 03-16-21 at 12:30 PM ----------
I just found 9V (4.8V) Li-ion rechargeable 780mAh block batteries exist.. seems like a good candidate for a stronger battery holder
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