My automatic watch stops overnight: why it happens, and the one move that fixes it
7 am. You reach for your watch on the bedside table and it reads 3.12. The seconds hand is not moving. It was running perfectly last night when you took it off. Broken? Flat battery? There is no battery. And in the vast majority of cases, nothing is broken either.
An automatic watch that stops overnight has simply run out of energy. It winds itself from the movement of your wrist and stores that energy in a spring. If it was barely worn the day before, the spring runs down during the night and the watch stops. Seiko spells it out in the instruction manual for its automatic calibres: fully wound, the watch runs for about 41 hours, and to keep it well charged you need to wear it for more than 10 hours a day. The fix comes down to one simple gesture: around twenty turns of the crown. Here is how to do it, and how to spot the rare cases where something really is wrong.
What happens inside the case while you sleep
An automatic watch is a tiny power station. On the back of the movement, a half-moon weight called the rotor pivots with every movement of your arm. As it turns, it winds a spring, the mainspring, coiled inside the barrel. That spring then unwinds very slowly and drives the gear train, paced by a balance wheel that swings back and forth without pause. On Seiko's 4R automatic calibres, the balance beats at 21,600 vibrations per hour, or six per second: that is what gives the seconds hand its beautifully smooth sweep.
At night, nothing winds the spring any more. The watch keeps drawing on its reserve, and once that is exhausted, the balance comes to a standstill. If it stops at 3 in the morning, that is simply the moment its reserve ran dry.
41 hours on paper, far fewer in real life
Seiko's 41 hours assume a fully wound watch. But a mainspring does not fill up during an hour at the office. The manual is clear: a watch used without being fully wound may gain or lose time, and to avoid this you should wear it for more than 10 hours a day. A day spent sitting down, wrist resting on a keyboard, does very little to wind the spring.
| Your day | What happens overnight | What to do |
|---|---|---|
| Watch worn for more than 10 hours, active day | It runs through the night as normal | Nothing |
| Worn for 3 or 4 hours, mostly sitting down | Likely to stop in the early hours | A few turns of the crown in the morning |
| New watch, or one left in its box | Mainspring almost empty, stops quickly | Wind it fully by hand before wearing it |
| Taken off on Friday evening, picked up again on Monday | Stopped at some point on Sunday, even if fully wound | Wind it, then reset the time and date |
| Worn every day but still stops | Not normal | See below: magnetism, knocks, servicing |
The weekend scenario is easy to work out: put down fully wound at 8 pm on Friday, a watch with a 41-hour power reserve stops at around 1 pm on Sunday. Nothing to do with a fault.
The right habit: twenty turns of the crown
Seiko's manual explains how to restart a stopped watch: turn the crown 20 times by hand to wind the mainspring before setting it going. In practice:
- With the crown pushed in against the case, turn it slowly clockwise. Turning it the other way winds nothing. If the crown screws down, unscrew it first.
- Don't worry if the seconds hand does not start straight away. Seiko explains that an empty mainspring has little force at the start of winding: the seconds hand only starts once a certain tension has built up. Gently rocking the watch from side to side can help it get going sooner.
- No need to fear overwinding. According to Seiko, turning the crown further will not break the mainspring.
- Set the time by pulling the crown out to the last click. The seconds hand stops, so you can set it to the exact second. The manufacturer's tip: turn the minute hand back slightly, then bring it forward to the exact time.
- Screw the crown back down if it is a screw-down crown, without forcing it.
The mistake to avoid in the morning: a date that changes at noon
This is the trap almost every new owner falls into. Your watch stopped at 3.12. You wind it and move the hands forward to 7 o'clock. The catch: on the dial, 7 in the morning and 7 in the evening look exactly the same. If the movement actually thinks it is 7 pm, the date will change at noon instead of midnight, as Seiko points out in its manual.
The manufacturer's method avoids this twelve-hour offset:
- First, set the date to the previous day.
- Then turn the hands until you see the date click over to the next day: it is now midnight.
- Carry on to the morning time you want.
A second rule, just as important: Seiko advises against setting the date between 9 pm and 1 am, when the date mechanism is in motion. A watch that stopped in the middle of the night often falls within this window, all the more reason to move the hands past it before touching the date.
When it is no longer normal
A watch worn every day, for more than 10 hours, that still stops deserves a closer look. Seiko's manual lists the causes to check.
- Magnetism. The hairspring, the very fine spring that makes the balance oscillate, can be disturbed by a magnetic field. Seiko names the everyday culprits: smartphones, tablets, mains adapters, bags with magnetic clasps, electric shavers, magnetic cooking hobs and portable radios. For a watch with no specific marking on the caseback, the advice is to keep it more than 5 cm away from these objects. A magnetised watch gains, loses or stops altogether, and needs to be demagnetised by a watchmaker.
- A knock or vigorous sport. A drop or strong vibrations can upset the timekeeping. If accuracy does not return after resetting the time, the watch needs checking.
- No servicing. Oils age and parts wear. Seiko recommends an inspection with dismantling and cleaning roughly every 2 to 3 years, and lists "not serviced for more than 3 years" among the causes of irregular timekeeping.
Temperature, for its part, affects accuracy but does not stop the watch: according to Seiko, a mechanical watch tends to lose time at high temperatures and gain time at low temperatures. Our watches carry a 2-year warranty covering the movement and assembly: if yours stops even though you wear it every day, get in touch.
Do you need a watch winder for the night?
Watch winders, those small motorised boxes that keep a watch turning, are useful if you own several automatics and don't want to reset them every time. For a single watch worn daily, they are unnecessary: your wrist does the work, and twenty or so turns of the crown in the morning make up for a day that was too quiet.
The best winder is still your arm. A watch worn from 8 am to 7 pm, with commuting, stairs and ordinary everyday movements, comfortably exceeds the 10 hours recommended by Seiko. And it doesn't need to be on your most active wrist: find out why we wear it on the left wrist without it getting in the way of winding.
Open heart, or the art of watching your watch breathe
Some watches make the diagnosis instant. On our Nautmod, an aperture at 9 o'clock lets you see the balance beating through the dial. If it is still, the watch has stopped and there is no need to look any further. If it is beating, all is well, even if the seconds hand seems a little lazy.
Our other automatics, such as the octagonal S Royal or our blue-dial watch with a fluted bezel, are wound in exactly the same way, via the crown. To find out which movement powers each model, see our page on the movements in our watches.
Frequently asked questions
How long does an automatic watch keep running when it is not worn?
For its 4R automatic calibres, Seiko quotes around 41 hours once the watch is fully wound. In practice, a watch that was barely worn the day before can stop much sooner, sometimes as early as the following night.
Is it a problem if my automatic watch stops overnight?
No, that is simply how an automatic watch behaves when it has not been worn much. Wind it with around twenty turns of the crown, reset the time, and wear it for longer during the day so that it runs through the night.
Can you overwind an automatic watch?
No. Seiko states that turning the crown further once the watch is fully wound will not break the mainspring. Simply turn it slowly clockwise, with the crown pushed in.
Why does the date on my watch change at noon?
Because the time was set twelve hours out, often after the watch stopped overnight. Set the date to the previous day, move the hands forward until the date changes (midnight), then carry on to the time you want.
Can my phone stop my automatic watch?
It can magnetise it if you rest one on top of the other. Seiko lists smartphones among the magnetic objects to keep more than 5 cm away. A magnetised watch gains, loses or stops altogether, and needs to be demagnetised.
Sources
- Seiko, instruction manual for calibres 4R35 and 4R36, "Comment remonter le ressort principal" (41 hours, 10 hours a day, mainspring): seikowatches.com
- Seiko, same manual, "Caractéristiques de la montre mécanique" (20 turns of the crown): seikowatches.com
- Seiko, "Comment régler l'heure et la date (4R35)" (date changing at noon, 9 pm to 1 am window): seikowatches.com
- Seiko, "Résistance magnétique" (everyday objects, 5 cm distance): seikowatches.com
- Seiko, "Dépannage", "Précision des montres mécaniques", "Caractéristiques" and "Service après-vente" (servicing every 2 to 3 years, 21,600 vibrations per hour, effect of temperature): troubleshooting, accuracy, specifications, after-sales service
- Cover photo: simonprodl, Pixabay Licence, via Pixabay (pixabay.com).
- Movement photo: A_Different_Perspective, Pixabay Licence, via Pixabay (pixabay.com). Nautmod photo: SmodParis workshop.
The figures quoted come from Seiko's official instruction manual for its 4R35 and 4R36 automatic calibres. Most of our watches use the Seiko NH35, another Seiko automatic calibre, while our open-heart models use a Miyota automatic calibre. Seiko and Miyota are the movement manufacturers; SmodParis is an independent workshop, not affiliated with these brands.