# Bulova moon watch battery type and clues when replacement is required



## Light15

Just bought a pre-owned Bulova moon watch on a strap, with the box and NATO velcro strap. It is six months old, according to the warranty card. What is the battery type required for replacement. What clues will one have that the battery needs replacing? Is it time loss or gain? Or do the hands indicate that the battery needs replacing. Went on the Bulova website, but could not find a .pdf image of the manual or any clues as to care of the specific UHF watch. b-)


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## Light15

I found a youtube video about the inside of the Bulova moon watch




He suggests it takes a SONY SR927W, does that conform to what you know?
And what are the indications the battery is needing to be changed?


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## Light15

The watch has arrived. It is a beauty, especially having handle an Omega Moon watch in person. The instructions helpfully note that you can leave the crown OUT as this WILL save power, although the quartz crystal will continue to vibrated (not the case on all quartz watches, sometimes merely a clutch to allow the hands to be moved). It was NICE the instructions confirmed this feature. BUT it does not mention the battery required.


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## odd_and_vintage_fan

AFAIK, it will just stop when it runs out of battery. The size is 399/395. Mine's at 2.5 years on the original battery thus far.

Edit: With no change in timekeeping thus far, as well.


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## peewee102

I bought mine in Dec. 2016, and the battery just died. Replaced with a 399 battery, and it's running again. It lasted over 3 years.


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## salendersmith

While having watch battery replacement, ask the expert to use the original battery so that it will run longer than estimated.


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## stockae92

Light15 said:


> I found a youtube video about the inside of the Bulova moon watch
> 
> 
> 
> 
> He suggests it takes a SONY SR927W, does that conform to what you know?
> And what are the indications the battery is needing to be changed?


it has quite a big movement may I say.

regarding to pulling the crown out to save the battery. I imagine if the gasket sits on the crown tube, and there is no gasket the crown would be pushing against, then the water "proofness" should not be affect?


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## ObiWonWD40

odd_and_vintage_fan said:


> AFAIK, it will just stop when it runs out of battery. The size is 399/395. Mine's at 2.5 years on the original battery thus far.
> 
> Edit: With no change in timekeeping thus far, as well.


The 399/395 battery seems to be quite common for watches with Chronograph movements. A lot of Seiko, Citizen and a few Swiss brands also seem to use that battery too.

The CR2016 seems to be used where you have a movement that uses a Smooth Sweep Second Hand, in designs like a typical three hand watch with the Date complication too. The Timer hand Sweeps on the Lunar Pilot, but the small Second Hand moves twice a second and I assume that this takes far less power than the large continuously running Sweep Second Hand.

Apart from the Lunar Pilot, I have another couple of Bulova Watches that the best description I can offer here is, that they are basically a Lunar Pilot Example but in different clothes. From my experience is that the batteries with modest Chrono Timer Useage will last approximately around 3 Years. Once the watch shows signs of not keeping accurate time and is loosing a few seconds here and there, it is time to fit a new battery. Not too bad a job and if you have been used to changing a battery on most watches, then the Bulova is not a problem.

The documentation is rubbish in comparison to manufacturers like Seiko. On some Seiko movements you have to reset the movement by shorting out the "ac" probe point on the movement with conductive tweezers. But it says nothing about this anywhere and no point is marked "ac" that I can see and the watches seem to run OK, so I assume it does not need it. Some Seikos like the current Mecha-Quartz Chronos use this methodology, but not all do. But it would be nice to know if there is anything that needs doing. I just take care and use non-conductive tweezers, so I don't accidentally short out anything! Strangely, Miyota aka Citizen publish as good a set of information as Seiko do, I just wish that Bulova would get the same habit!

Best regards,
Jim


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## tmathes

ObiWonWD40 said:


> The 399/395 battery seems to be quite common for watches with Chronograph movements. A lot of Seiko, Citizen and a few Swiss brands also seem to use that battery too.
> 
> The CR2016 seems to be used where you have a movement that uses a Smooth Sweep Second Hand, in designs like a typical three hand watch with the Date complication too. The Timer hand Sweeps on the Lunar Pilot, but the small Second Hand moves twice a second and I assume that this takes far less power than the large continuously running Sweep Second Hand.
> 
> Apart from the Lunar Pilot, I have another couple of Bulova Watches that the best description I can offer here is, that they are basically a Lunar Pilot Example but in different clothes. From my experience is that the batteries with modest Chrono Timer Useage will last approximately around 3 Years. Once the watch shows signs of not keeping accurate time and is loosing a few seconds here and there, it is time to fit a new battery. Not too bad a job and if you have been used to changing a battery on most watches, then the Bulova is not a problem.
> 
> The documentation is rubbish in comparison to manufacturers like Seiko. On some Seiko movements you have to reset the movement by shorting out the "ac" probe point on the movement with conductive tweezers. But it says nothing about this anywhere and no point is marked "ac" that I can see and the watches seem to run OK, so I assume it does not need it. Some Seikos like the current Mecha-Quartz Chronos use this methodology, but not all do. But it would be nice to know if there is anything that needs doing. I just take care and use non-conductive tweezers, so I don't accidentally short out anything! Strangely, Miyota aka Citizen publish as good a set of information as Seiko do, I just wish that Bulova would get the same habit!
> 
> Best regards,
> Jim


I have not replaced my L/P battery, which is just a couple months shy of 4 yrs. old but have had to replace the battery in my Curv, which has a similar movement to the L/P. There was no need to do anything when I installed the battery, the watch just started running again. I've rarely found any watch I own that needed the momentary reset to get them running again even if the provision is in there.


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## Burgs

A few of my watches have the battery type marked right on the outside of the case back. I wish that more watch companies did that.


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## ObiWonWD40

Just a bit more info on the Bulova Lunar Pilot "Moon Watch" Movement

"Bulova Caliber 8136
Manufacturer Bulova (Citizen/Miyota) Caliber Number 8136 Type Quartz Lignes 15"' Diameter 34.6mm Height 4.9mm Total Height 8.5mm Battery Cell SR927W..."

This from Calibre Corner

https://calibercorner.com/bulova-caliber-8136/

Best Regards,
Jim
Stay Safe; Stay Well :-!


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## MichaelxXx

Light15 said:


> I found a youtube video about the inside of the Bulova moon watch
> 
> 
> 
> 
> He suggests it takes a SONY SR927W, does that conform to what you know?
> And what are the indications the battery is needing to be changed?


The manual states that the battery is good for one year.


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## RedRubyRacer

"Once the watch shows signs of not keeping accurate time and is loosing a few seconds here and there, it is time to fit a new battery." Thank you so much for that !! Common dictum is that the watch will stop functioning altogether when a low charge is reached , period , end of story; change the battery, according to the manual , Eddie at Bulova NY, and service in São Paulo , Brazil . None of the above seem to know what the fudge they´re talking about. However , my four year-old LP has frequently lost "a few seconds here and there" , I have noticed especially when the temperature drops . With your input I will no longer consider getting rid of it , and will buy a little tool to open the back plus a stash of batteries for this watch which I like . Thank you , Jim !


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