Is that caseback different to the original watch then?
At any rate, I would use Renata battery 301 which measures 11.6 x 4.2 mm.
If you could measure the smaller battery that came out and match that with the Renata 301, you can verify if this will fit.
(the objective being of course that the Renata 301 is slightly larger than the small battery with the paper)

 

Case back could be different to the watch but both case back and dial refs take the same battery.
The case back is exactly the same as others with the dial ref. its just a Grand seiko case back.

 

Anyone else found this seiko brand of battery to big to fit?
What is the difference between Renata battery 301 & Seiko battery 301?

 

I think the simplest solution is to just measure the small battery that came out with the paper shim and choose a slightly larger battery that would fit precisely.
Remember that this is a quartz from the 1970's. It's not exactly a current model.

 

Seiko 301 is 11.4mm x 3.9mm.
Any 301's that are slightly smaller diameter then the Seiko 301?

 

I believe you're barking up the wrong tree by referencing to the Seiko 301 battery THAT DOESN'T FIT. It's the wrong spec.

I think the battery that was in it is a Murata SR927 silver oxide 1.5 battery and it measures 9.5 mm by 2.7mm.
To confirm these measurements, please measure the small battery that came out and more or less fits with the use of a paper shim.
You need a battery slightly larger than that.

After that, please look up Renata 394 which measures 9.5 mm by 3.6mm.
Link to RenataRenata 394

I hope this solves the issue.

 

I cannot thank you enough for this info.
I have now ordered the Renata 394 battery.
I am new to vintage seiko watches. First battery change.
I checked the battery Mizeni website for battery size & just assumed it will fit.
Only noticed the small battery when I came to change over.
Is this a known issue with 1970s Seiko watches?
ie Not all recommended battery diameters/depths will fit the watch?
Thanks again Rgds Lawrence

 

You're very welcome.
Owning a vintage watch, quartz or mechanical, can sometimes be challenging.

Please report back once the new battery is fitted and all is working properly!

I cannot thank you enough for this info.
I have now ordered the Renata 394 battery.
I am new to vintage seiko watches. First battery change.
I checked the battery Mizeni website for battery size & just assumed it will fit.
Only noticed the small battery when I came to change over.
Is this a known issue with 1970s Seiko watches?
ie Not all recommended battery diameters/depths will fit the watch?
Thanks again Rgds Lawrence

 

Hi, Lozboy--The 48xx movements were made in two versions, A & B. The B version is later than the A version and replaces it. The B version uses a smaller battery, which allows the watch to be made about 1 mm thinner. The second number in the designation 4843-8110 indicates the B movement (IIRC). (On Seiko watches, there is no necessary agreement between the dial number and the number on the case back.)

I believe the battery indicated for this watch is the SR936SW = E394. One can find Seiko movement battery reference tables online, with a little looking.

Enjoy your watch!

ReggieH

 

I think the Renata 394 is compatible with that E394. It's in the name too of course.
We'll find out in a short while!

 

Many Thanks for that info.
I will research a little harder before the next battery change.
Need to frequent this place more often.
Which is the best forum group on here for newbies
Asking basic Q's?