The Breitling Watch Source Forums

0.07 per day =25 seconds per year.

Right. If I understand it correctly, that means Breitling's standards are more stringent for their SQ watches than the COSC's. COSC certification represents a floor, not a ceiling.

0.07 is only 25 seconds a year if you ignore the + / -.

Quartz accuracy is affected hugely (relatively) by temperature - that's why thermocompensation improves accuracy. There is no way that a quartz or superquartz watch will gain or lose the exact same time every day unless it is kept in a thermally controlled environment - and your wrist isn't.

Believe it or not, having plaved in the field of environmental testing (they guys who shake and bake electronics etc) your wrist can be a reasonably WELL controlled environment when it comes to TEMPERATURE (it's a NASTY place for shock and vibration). There is the rather large self regulating heatsink right in back of the watch (YOU) - if that "cool plate" changes more than a few degrees there are all sorts of issues

This is actually a fairly GOOD reason for a "plastic" watch with a metal backplate (see Traser watches etc) The temp swings you get are then FAIRLY small, at least by electronics design standards (then again, we expected stuff to RUN from -40C to about 50c for human carried stuff, and a lot of stuff went from -40c to 90c+ operating, and -70c to around 110c storage - not 100% on that last number)

Fair enough, but the scale is rather different with quartz watches - those "few degrees" can make a huge difference relative to the numbers that we are talking about. The COSC test for quartz actually involves three temperatures - +8 / +23 / +38 (all celsius) and the acceptable error rates are + / - 0.2 / 0.07 / 0.2 respectively. Small numbers, but an error three times as great at the two extremes as at the midpoint.

Of course there are also changes caused by putting your watch in water, taking it off for the night, etc.

I'd actually BET there is more difference in temps when you are NOT wearing the watch. One of those "odd" things

And yes, there are a TON of 'other' environmental factors - add in things like swimming, and particularly if your are wearing the watch outside your dive suit, you are in for fun. It's still amazing they are as accurate as they are

It looks like temperature variations affect the accuracy more than other factors.

So Breitling SQ watches should be +/- 15 seconds a year (or less).

Actually, it is +/- 25.55 sec/yr ( .07 sec/day) to meet COSC standards for quartz movements. Typical Breitling SuperQuartz movements (ex: the A78 in the SQ B-1 which is an ETA "Thermoline" based on the ETA 251.332) perform much better in real life, often losing or gaining well less than 10 sec/yr ( ETA's own specification for the Thermoline movements) even though Breitling touts the SQ calibers at around +/- 15 sec/yr. The A68362 non-SQ (ETA E20.331) B-1 should still regulate quite easily to better than +/- 20 sec/yr if the battery is within specification and the movement has no negative issues to be resolved. Same applies to the non-COSC certified model A68062 (1998 -1999 and some early 2000 pieces ) because it is the identical movement as the A68362 model B-1.
Best,
Ron

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Not quite.

COSC doesn't provide an annual number, that's just a combination of marketing / consumer translation into something that seems more meaningful. Ask the COSC what the specs are and they'll tell you + / - 0.07 per day at 23 celsius. I know that translates to 25 and change at each extreme, but that's no more valid than the assumption that the temperature will remain at 23 celsius all year. Also, and often lost, COSC allows variation of 0.05 seconds per day, a high percentage on a 0.07 second error.

That's in large part why ETA can claim + / - 10 and Breitling can claim + / - 15 - in quartz movements more than mechanical the error rate is far less predictable and hence you get offsetting errors over time.

Does the positioning of the watch (up, down, sides) affect the accuracy and in which does more-quartz or mechanical?

Hi, Roff. Yes, of course you are correct and I was already knowledgable of the facts as you present them having read specification documentation from the COSC many times. I only posted a simplistic translation to help illustrate what the OP might expect from his B-1 if it has been regulated properly.
Best,
Ron

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"The Sailor Who Fell From Grace With The Sea"...

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It affects mechanical watches and has been discussed here many times, it doesn't affect quartz (at least not materially).

Good thread but I am now Dizzy!!!

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Breanach78

A Few Breitlings.