Watches lovers

[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.

   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.

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.

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 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]

   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!

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]

...
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. 😁

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.

[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 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. 😁

Sorry for the late reply.  Somehow I missed these messages.

I've read that the first Eco-Drive watches used supercaps, but they quickly realized that supercaps just didn't have enough capacity to be practical so they switched to rechargeable batteries.  But I think the marketing types still want to refer to it as a capacitor so that they can claim that there are no batteries to replace.

Ed

[edpalmer42]

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.

If they use an LED, I've never seen it.  I read a report from a user that the open-circuit voltage from the solar cell is ~1V8.  That's well within the safe charge voltage - actually, it's a bit low - so I wondered if that was their 'overcharge protection'.  I've also seen one Technical Information document that show battery voltage of up to 2V6 so that couldn't be an LED.

I've only worked on two Eco-Drive watches, but they both had a test point for the battery's negative terminal.  It's marked (-) .  I've used this to track the charge state of the battery during my testing.  Once the voltage reaches ~1V65 it starts to climb rapidly.  I've considered that to mean that the battery is fully charged.

My light source is a high-intensity LED desk lamp.  The head of the lamp is shaped like a spotlight that happens to be 40 mm in diameter.  My light meter says that when the head is about 25 mm from the meter the light intensity matches the midday sun.  Since the lamp is above the watch, any heat it does generate rises away from the watch.  You'd think the lamp was designed for charging solar watches!

Ed

[Zucca]

https://www.sensorwatch.net/

I have one and I it will probably be my last watch purchase. Very very happy.

[TimFox]

Two unrelated comments relevant to mechanical watches.
1.  Developers of high-resolution x-ray imagers, where time was also important, found pocket watches to be ideal test objects.  A good high-speed imager could resolve the fine internal components even though the guts were oscillating.  Apparently, European and American mechanical watches use different standard oscillation frequencies, and pocket watches tend to be slower than wristwatches.
2.  My mechanical watch is a Russian "Mikhail Moskvin" manual-wind watch, 17 jewels, with a transparent back, good to 3 Atm.
I purchased it in Uglich, during a tour in 2018, after the factory had closed a few years before.  I'm not sure if this is really an older Soviet make, or a recent re-branding of foreign movements.

[Gyro]

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.

If they use an LED, I've never seen it.  I read a report from a user that the open-circuit voltage from the solar cell is ~1V8.  That's well within the safe charge voltage - actually, it's a bit low - so I wondered if that was their 'overcharge protection'.  I've also seen one Technical Information document that show battery voltage of up to 2V6 so that couldn't be an LED.

I've only worked on two Eco-Drive watches, but they both had a test point for the battery's negative terminal.  It's marked (-) .  I've used this to track the charge state of the battery during my testing.  Once the voltage reaches ~1V65 it starts to climb rapidly.  I've considered that to mean that the battery is fully charged.

My light source is a high-intensity LED desk lamp.  The head of the lamp is shaped like a spotlight that happens to be 40 mm in diameter.  My light meter says that when the head is about 25 mm from the meter the light intensity matches the midday sun.  Since the lamp is above the watch, any heat it does generate rises away from the watch.  You'd think the lamp was designed for charging solar watches!

Ed

I can't remember where I read about the LED (maybe that was an early implementation too), but the movement information does indicate that there is an overcharge protection circuit... https://www.citizenwatch.co.uk/media/calibres/E031/E031_ebook.pdf