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RJSV:
   Miti:
   Is it possible to bypass the lack of explicit formula, (at least in the short term),  by coming up with ways to measure the lift angle, like perhaps a high speed video recorder.
   I understand that might not be any easier, but at least you could identify any barriers to doing things empirically.

Anyway, wanted to make sure you know that the thread here is appreciated and read with enjoyment!
   One doctor this month had a feature filled watch he was using, (checking pulse).  Next time, I want to ask about his interest in all things mechanical time!

edpalmer42:
Has anyone dug into the bowels of the Citizen Eco-Drive watches?

If you're not familiar with them, they're quartz watches with a solar cell to charge an internal rechargeable lithium battery.  The battery is designed to last for at least 10, maybe 20 years.

I recently picked one up on an impulse for the princely sum of C$25.  "Needs a new battery."  No, the battery just needed charging - a process that takes days if the battery is completely flat.  That process is underway and seems to be going well.  The voltage of the MT621 battery is ~1V4 as compared to a nominal 1V5.  The problem is that this watch also has a 'Power Reserve' dial that shows the state of charge of the battery.  So far, it hasn't moved.  There's no tech info online to explain exactly how this thing is supposed to work - i.e. something like 0% = 1V4, 50% = 1V45, 100% = 1V5.  All I found is info stating that there were problems with the feature.

Has anyone experimented with these things?  Is 1V4 not enough voltage for them to react?  Is there a simple fix?  I'm considering removing the battery, which is trivial to do, and externally charging it but I'm holding off on that until I see what voltage the solar cell manages to charge to.  Apparently the open circuit voltage from the solar cell is ~1V8.

FYI, I've attached one of the auction pictures.  Yes, there are scratches on the crystal.

Ed

Miti:
No, I didn't leave this thread but… life - work “balance”, pun intended.


--- Quote from: RJSV on June 01, 2024, 10:49:29 pm ---   Miti:
   Is it possible to bypass the lack of explicit formula, (at least in the short term),  by coming up with ways to measure the lift angle, like perhaps a high speed video recorder.

--- End quote ---

There are different methods to find the lift angle, the one where I apply a known stimulus and see if the timegrapher measures correctly could be one.


--- Quote from: edpalmer42 on June 08, 2024, 05:56:17 pm ---Has anyone dug into the bowels of the Citizen Eco-Drive watches?

If you're not familiar with them, they're quartz watches with a solar cell to charge an internal rechargeable lithium battery.  The battery is designed to last for at least 10, maybe 20 years.

--- End quote ---

I have one, my wife has two. Citizen has warehouse sales twice a year and we bought at relatively good price.
Is it Lithium or supercap? I read somewhere that it is supercap. I never opened one but… now that you mentioned. 😁

watchmaker:

--- Quote from: RJSV on June 01, 2024, 10:49:29 pm ---   Miti:
   Is it possible to bypass the lack of explicit formula, (at least in the short term),  by coming up with ways to measure the lift angle, like perhaps a high speed video recorder.
   I understand that might not be any easier, but at least you could identify any barriers to doing things empirically.

Anyway, wanted to make sure you know that the thread here is appreciated and read with enjoyment!
   One doctor this month had a feature filled watch he was using, (checking pulse).  Next time, I want to ask about his interest in all things mechanical time!

--- End quote ---

With the exception of the Omega Coaxial, virtually all modern watches (since 1970) have a nominal lift angle of 52 degrees.  Hamilton pocket wathces use 48 degrees and other pocket watches can go down to 42 degrees.

However, the lift angle for a specific movement can be +- 2 degrees different from nominal.  This is because of adjustments needed to "match the escapement" which means ensuring the escapement works as efficiently as possible.
 
Here is a link to an article (that is too large) which describes the process (with photos) for adjusting the escapement for precision timing.

historictimekeepers.com/documents/Watch Adjustment.pdf

Gyro:

--- Quote from: Miti on June 28, 2024, 05:43:10 pm ---...
I have one, my wife has two. Citizen has warehouse sales twice a year and we bought at relatively good price.
Is it Lithium or supercap? I read somewhere that it is supercap. I never opened one but… now that you mentioned. 😁

--- End quote ---

Likewise, we both have one.

Irrc, Citizen Eco-Drive use a Lithium-titanate (LTO) cell rather than a supercap. So do Seiko Kinetic watches. They have high charge-discharge cycle life and good operating temperature range*. I think the Eco-Drive uses an LED in a basic overcharge protection circuit.

I've read of several examples of these cells not recovering from deep discharge, including a thread on here somewhere, so it's important to pull out the crown to the second stop if you are putting them in storage. This matches my own experience too, where my old, stored in the dark, Eco-Drive watch won't come out of low battery indication no matter how much sunlight it gets. Luckily the cell is replaceable.


Edit: * ...and fast charge acceptance, important if you want to get the most out of occasional glimpses of strong sunlight.

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