The Watch Site banner

Eco Drive Accuracy Report...

15884 Views 16 Replies 7 Participants Last post by  Fastest
...mostly anyway. After gaining a fair few Citizen Eco Drives during the past year or so, i set them all to atomic time at the beginning of the year and have kept tabs on how they've performed purely for my own amusement.

I thought id share the results with the members here and invite others to let us know how their eco drives have been performing. Maybe we can get a fair idea how these movements perform if we get a large enough database. Obviously all radio controlled models should be excluded from this, (even though two of mine are rc, as im in oz, none receive any signals and thus only operate as standard quartz).

my rate results (all watches except where noted set on 28/1/10):

Citizen AS8009-53E = +4sec/month

Citizen Calibre 2100 = -2sec/month

Citizen Nighthawk = +4sec/month

Citizen World Time = +6sec/month

Citizen BJ2120-07E = +8sec/month

Citizen BN0065-55E = +8sec/month

Citizen JP3040-59E = +3sec/month (digital display)
(battery powered) = -5sec/month (analogue display)

Citizen PMD56-2972 = +/- 0sec/month (measured 2wks only)

Citizen JR3090-58M = +4sec/month

Citizen BL5280-52W = +9sec/month

and as a reference from two others i measured:

Casio EF-524SP-1A = +10sec/month (measured 2 wks only)

Tissot T-Touch = +2sec/month

I hope this was of interest to someone
...surprised?, as expected?, let us know what you guys are getting.
This is my first post here, i see many regulars from other joints ^-^ , pleased to be here, thanks for the invite John, cheers.
See less See more
1 - 3 of 17 Posts
I'd say that those are pretty decent results for ordinary quartz movements. As noted earlier, if you were to wear each for at least 12 hours per day, the results would probably be better. This is because it's probably the case that the watch makers calibrate the rate to be at its best when the watch is worn. However, one point made earlier in this thread is incorrect: non-TC movements don't tend to go faster when warmer (or more precisely, this is true for only a small part of the temperature range). If this were true, it would suggest a linear relationship between temperature and rate, and no such relationship exists with quartz. The relationship is quadratic, or in the form of a parabola, with the parabola crossing the 0 sec./month line at two points, one at a relatively cool temperature as the parabola rises, and then again at a warmer temperature after the parabola has reached its maximum height and is now on the way down again. With some movements, the calibration is really good, so that the first point occurs near room temperature (say 70F) and the second near typical 'wearing' temperature (about 86F: ambient temperature blended with skin temperature of about 91F). This perfect calibration is rarely seen, however, in normal quartz watches, and, if you're lucky, you will have the 'wearing' temperature coincide with something close to 0 sec./month.

You have established some good, reliable accuracy values for off-wrist performance. It would be great if you took one watch at a time and wore it for, say, one-two months (perhaps something like 12 hrs. on/12 hrs. off, or better, 14/10) to get its 'wearing' performance. You could use the Stopwatch Method detailed in a sticky on the WUS-HEQ forum, or, if you prefer, just do it by eye.
See less See more
brett said:
btw, how did your testing with Franks chronomaster and bulova go? im not sure i remember seeing the final results posted? was it abandoned? im more interested in those tbh :57: ;D
Well, we got to a 4-week time period with Frank's Bulova Precisionist Claremont model, with the 'on-the-wrist' condition (12/12 or 14/10), and the results were pretty good: +11.32 seconds per year, which, in my opinion, is terrific for a non-thermocompensated watch movement. Rather than continuing with the 'on-the-wrist' condition for a longer period of time, we then went to the 'off-the-wrist' condition, but only got two weeks' worth of data. Over that time period, Frank's Precisionist showed +7.40 seconds per year, but two weeks is too-short a timing period to have much faith in the results. At that point, testing stopped. Still, I think the results that Frank got (and one or two others have as well) suggest that this new 3-prong, high-frequency crystal technology has real promise.
brett said:
wow, excellent to see that at least the marketing wasnt frivolous. mostly though im surprised that the off wrist performance increased vs on wrist given as you say the manufacturers try to calibrate for on wrist accuracy.
Yes, a little surprising. Below is a link to a thread started by dwjquest on the WUS HEQ forum that gives some excellent temperature X rate data on a Bulova Precisionist. Dwjquest uses advanced technology to track oscillator frequency and does so at precisely-stated temperature points (which he controls with some sort of oven). You'll see two separate tests there, and the results are almost identical. "Off-the-wrist" temperature is difficult to peg precisely, as it will vary from one person (and environment) to another, but I've used 70F as a good temperature equivalent. "Wearing" temperature can be generally pegged at about 86F. This arises from the combination of the temperature of the surface of the skin (about 91F) and the ambient temperature; 86F seems to be about right. If you look at dwjquest's excellent graphs, you'll see about 10 seconds per year for 86F and 8-9 seconds per year for 70F. In Post #21, you'll see the results minidriver and I got with his Precisionist--very close to dwjquest's values.
See less See more
1 - 3 of 17 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.