Watch Winder Review and Analysis - Part I & II

[ten10]

Disclaimer
Everything in this review expresses my thoughts and opinions. You have your opinions and so do I. I intend this to be as informative as I can, accurate to the best of my knowledge.

I do not represent any manufacturers, their respective distributors or agents of this particular watch winder. My goal is never to disparage anyone or any company but to share my opinion and give a review from my perspective, based on my technical and manufacturing background. It is up to the reader to decide for themselves after reading and looking at the photos I’ve taken, and also viewing the insides of a winder since opening theirs would void warranty.


Introduction
On 28th Oct this year, my childhood friend pulled the trigger and got himself a watch winder. The next day, Simon dropped by to show me his new toy and asked for my opinion.

This was the review (PART I ~ PART V) I gave him…


PART I

The Aesthetics
This is an unbranded watch winder and picture below shows how it looks like.


1) Exterior
- High-gloss piano finish
- Suspect its not solid wood but wood motif paper foil wrapped and sprayed with lacquer to cover up. This will be confirmed later.
- Silver-tone hardware (lock & key)
- Clear plastic viewing window, not real glass
- Power switch and socket at the rear

2) Interior
- Two rotating pods; each having two slots for watches
- The two slots are designed too close such that watches will elbow each other
- Six additional slots for watch storage provided
- All pillows are rather stiff/hard and users with smaller wrist may find it difficult to clasp their bracelets over it.
- Watch buckles beyond 35mm width definitely can’t fit inside slots
- Two mode selector knobs on front panel; one-to-one pod winding controls
- Silver-tone hinges
- Black synthetic leather lining

3) Functions & Features
- The unit has only directional selection and somewhat fixed TPD
- The seller doesn’t have details on how much TPD it delivers; I will confirm this later in PART III
- Each winding pod rotates silently and smoothly
- Unit works on 3Vdc
- Unit can be powered by AC Mains or 2AA batteries which I find quite strange as the battery capacity isn’t enough to last more than a week. More on this in PART II.

Other than the above, this is a straight forward affordable watch winder that works with no frills.

Modes of Operation
According to the seller, there are 5 modes of operation but IMHO mode1 is not counted as it just functions as a secondary ON-OFF switch.

Mode1:- OFF
Mode2:- Clockwise 2 minutes, Stop 6 minutes (repeats whole day)
Mode3:- Counter-clockwise 2 minutes, Stop 6 minutes (repeats whole day)
Mode4:- CW 2min, Stop 6min, CCW 2min, Stop 6min (repeat whole day)
Mode5:- CW 5min, CCW 5min (repeated for 3hrs) – Stop 9hrs (repeat)
Note: - I’ve timed the motor with a stopwatch and it makes approximately 10 revolutions per minute.




to be continued...

[triton]

2AA size batteries?

i wonder how long the battery will last. can help test?

- Unit can be powered by AC Mains or 2AA batteries which I find quite strange as the battery capacity isn’t enough to last more than a week. More on this in PART II.

[ten10]

Boss, steady can or not?

For the Test... see PART II

[ten10]

Watch Winder Review and Analysis - Part II

Disclaimer - Read Part I

PART II

Current Consumption
As I’ve mentioned, this unit uses 2AA batteries but I know the capacity is NOT enough as the highest available capacity for AA-type dry cells are only 2700mAH. From my experience in designing such winders, manufacturers normally deploy D-size dry cells instead! They have a larger capacity of about 18,000mAH. But maybe, the AA-size batteries are just for back-up. I really don’t know.

To calculate the battery life, I’ve to measure the current consumption first.

I’ve rigged some wires so that my ampere meter will be in series with the unit’s power adaptor.


I connected the circuit and start measuring the current.




Test Results
My test measurements consist of two parts: - With & without Load (watches)

Test Alpha - All pods are load-free, AC Powered and measured at intervals. First L-pod, then R-pod and then both.




Measured current with both pods rotating (load-free)



Test Beta - For the next test, pods are loaded with dummy weights, powered by AC and measured.




Note: - The weight of 143gm (approx) was chosen because it’s a mid-range weight of most Rolex models. The average weight of a SS Daytona with 13 links is about 140gm.


Battery Life
To calculate the battery life, 3 values are required and they are the battery capacity, current drawn when winder is in operation (rotating) and lastly, the winding sequence.

These are the known values for this winder…
Battery capacity: - 2700mAH (assume Alkaline batteries are used in this winder)
Current drawn: - 62.9mA (assume both pods turning with average weight of 286gm each)
Mode setting: - Position 4 (Mode4)
Winding sequence: - CW 2 min, Stop 6 min, CCW 2 min Stop 6 min (repeated whole day)
Firstly from the winding sequence, we know that the winder operates 6 hours daily or 25% of a day. Its ratio is 1:4.

Divide battery capacity by the current drawn: - 2700mAH/62.9mA = 42.93hrs
If the winder were to operate continuously, it’ll only last 42.93hrs or just over 1.7 days; however, we have determine that the winder works only ¼ of the time in a day.

Note: - At this point, I’ve eliminated current drawn during stops since 0.07mA is very insignificant and can be ignored.

Multiply 42.93 hrs by 4 you get 171.72hrs or 7.155 days

These AA batteries will drive your winder on full load for just 7 days. It is probably meant as a standby when you’re traveling and kept your watches on the winder in your safe or wardrobe.

Let's assume manufacturer chose to use C-size batteries...
Then, 8000mAH/62.9mA = 127.19hrs
127.19 x 4 = 508.76hrs or approx 21 days
By using C-size batteries, the winder would be able to drive both pods approx 21 days, three times longer than using AA-size batteries.

Simon, don’t worry about this. I’ll get the battery compartment modified for you.

to be continued...

[triton]

will anything happen to the winder if batteries are used and the winder is connected to the mains?

[ten10]

That’s a good question Triton.

For this winder, the DC socket disengages the battery contacts once the power jack gets hooked up.



For other winders, they have this and also a polarity protection diode placed in series with the battery positive as seen below.