[gutter rock]

I’ve managed to acquire two original Pentax 645’s, the original 1980’s versions. These have a lithium battery in the bottom to hold settings when you change the 6 AA’s in the grip. I will be keeping one body in storage for a backup and using the other one. Was wondering if removing the lithium battery on the stored one would be wise or harmful. I know lithium tends to be less likely to leak but it can happen. Any harm in not having it in there for possibly long term storage? Wouldn’t it be wise to remove it just to be safe? Some info on the web mentions that the camera may have to be reprogrammed if all power is lost, I have an extremely hard time believing that.

[gofour3]

I see no issue storing a film camera with no battery in it. (It came new from the factory that way)

Nothing to reprogram in an original 645, no "smarts" in that camera.

Phil.

[gutter rock]

That’s what I was thinking. Although the lithium battery was factory installed. Pentax originally wanted owners to send the camera to them for replacement and made the battery cover a bit hard to open. I do have a tool that will make it easy though. One person said the camera would lose its programming if it lost all power. I can’t see Pentax doing that, it isn’t a super computer. If so, wouldn’t all cameras from the 80’s and 90’s with program modes lose their functions when batteries die?

[Silent Street]

The lithium battery probably does little more than hold the ISO setting and the last modal settings used. It would have been put in there for a reason!
There are many, many cameras with factory-installed backup lithium batteries, among them are a lot in the Canon EOS line, including the EOS 1N, 1V and 5; The Canon T-Series cameras also had these batteries and many give an "EE-EEE" display warning when the battery is on the way out. These lithium cells are used to hold ISO, custom function, modal and metering settings when the main power source is removed (in the Canon case, either a 2CR5 battery or 8 x AA batteries in the power drive booster). The lithium backup battery in my EOS 1N is still going after 24 years...

[Alex645]

Was wondering if removing the lithium battery on the stored one would be wise or harmful. I know lithium tends to be less likely to leak but it can happen. Any harm in not having it in there for possibly long term storage? Wouldn’t it be wise to remove it just to be safe? Some info on the web mentions that the camera may have to be reprogrammed if all power is lost, I have an extremely hard time believing that.

Iʻve owned a 645 since 1986 and have never had the lithium replaced and have had the camera in storage many times without issues of leaking or even the battery dying. Hard to imagine the battery has lasted 32 years, but it has.

From my point of view, there is a greater risk at removing it, than leaving it alone. "I cannot confirm or deny" if taking it out will result in the need to reprogram the camera, but there is a reason why Pentax did not make this a user-friendly option like most button cell batteries....and I would err on the conservative side here. "Let it be."

[gutter rock]

I guess I will leave it in. I have no idea how old the battery is. It just seems that if the camera would need reprogramming if that lithium battery died then there would be a ton of Pentax 645’s out in the wild needing this service, which doesn’t seem to be the case. I wonder how many 645 owners don’t even know about that battery? Thanks for the suggestions. Would love to know the definitive truth. I’m guessing Pentax would probably not offer much insight on this old of a camera.

[Alex645]

On page 67 of the ownerʻs manual, it states that the battery is designed to last for 5 years. But as I mentioned, mine as lasted more than 6x longer than that, and if you read further in that section of the manual, it states the battery is just a back up precaution when the main power pack (of 6 AA) is being replaced or the power grip is removed.

So it appears it the lithium is only being drained when the main power grip is removed or the AA batteries are dead or removed.

The ownerʻs manual does imply that if the lithium battery is dead (or missing) AND the power grip is removed, that the camera does have to be sent to Pentax and I doubt it is just to replace the lithium cell. The CR1220 3V lithium cell is inexpensive and not hard to find.

http://www.cameramanuals.org/pentax_pdf/pentax_645.pdf

In my experience, itʻs best to schedule to run at least one dummy roll through your 645 every 6-12 months. The electronics (and probably mechanical gears) doesnʻt like to sit idle for too long. Same with lenses setting them at various aperture settings now and then. Not quite like the human "use it or lose it" but a little use now and then will go a long way in its longevity.

[gutter rock]

Well, I guess I will be buying two lithium batteries this weekend! This should probably be more common knowledge or there is likely to be a lot of Pentax 645 paper weights in the near future.

[gutter rock]

Okay. A follow up on the lithium battery situation. Got some new batteries, went to install them and one of my 645’s didn’t even have a lithium battery installed and hasn’t had double AA’s in the grip for months. So, I call B.S. on the scare that leaving the 645 without power for extended time will erase the programming of the camera. It appears the lithium is only there to remember your settings and exposure number should you have to change the AA’s mid roll. I thought that would have been a ridiculous design from Pentax if it had needed constant power. Plus, if this was the case they would be an ocean of these cameras out in the real world that were in need of reprogramming. Just thought I would report back in case someone wonders the real deal later on.