# A Rare Landeron Accumulator



## Sisyphus

Browsing eBay-UK today, I came across a listing for a watch that Silverhawk describes on his website as "extremely rare." Indeed, he says that he has never seen one for sale.

The movement is the rarity: an accumulator version of the Landeron 4750 that can be recharged using a conventional battery. For his discussion and some photos, go here: http://www.electric-...s/batteries.php.

Two photos of the watch for sale appear below. The listing is item number 140789058864. As I write this, the auction has 6 days and 2 hours to run. I am fairly certain that one person I Know will be among the bidders.


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## Silver Hawk

Sisyphus said:


> I am fairly certain that one person I Know will be among the bidders.


It's already in my watch list and I've already spoken to my bank manager.


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## Drum2000

Good luck Paul!


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## Vaurien

Silver Hawk said:


> Sisyphus said:
> 
> 
> 
> I am fairly certain that one person I Know will be among the bidders.
> 
> 
> 
> It's already in my watch list and I've already spoken to my bank manager.
Click to expand...

May the best win the auction!

(Paul is the best for sure :yes: )


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## mel

Silver Hawk said:


> Sisyphus said:
> 
> 
> 
> I am fairly certain that one person I Know will be among the bidders.
> 
> 
> 
> It's already in my watch list and I've already spoken to my bank manager.
Click to expand...

If my Lottery Ticket comes up - - I'll let you know how much you can go up to Paul :yes:

Best of Luck!


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## Mechanical Alarm

Okay... who got it and for what??


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## harryblakes7

I think it will go cheap, as the chap has listed it as "Swisselectric" all one word, and if you search electric watches it won't come up.............so you may not have too much of a battle on your hands, although there is a reserve price.................

Hope you get it Paul, i know what its like hunting that grail watch............... still searching for mine...........


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## Silver Hawk

Mechanical Alarm said:


> Okay... who got it and for what??


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## mel

Congratualtions Paul TTIWWP as soon as!







:yahoo: :tongue2: :thumbup:

A pictorial tutorial on the restoration would be "just wunnerful" :yes:


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## harryblakes7

Well done Paul............ does it have a battery in the case back which is charged up when you plug another one into the side? is that right? Would be great to see some close up pictures.......... :yes:


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## FuriousPig

Now that's a fantastic looking watch. I am green with envy.

It's the case design I absolutely adore; I had assumed (wrongly?) that it was 'Midland' that used it. I have a huge search string to catch this type which includes a billion permutations on the word Asymmetric & it still missed it. 'Isometric' indeed!!

So how many watches used this case?

Congratulations Paul, I don't really mind losing to the person who introduced me to this world.


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## Silver Hawk

FuriousPig said:


> So how many watches used this case?


"Midland" does seems to be the most common (wrong word!) one but I think I've seen another ... but cannot remember what was on the dial.

I'm quite pleased to be getting this new watch; my first significant purchase for sometime. The "swisselectric", ESA logo and "4750" on the dial all indicate that this was probably a demonstrator / exhibition watch. And as Sisyphus points out, certainly the first accumulator version of the Landeron 4750 movement that I've ever seen for sale; they were not produced for very long. I only know of three; all owned by the same collector and all with "Avia" on the dial.

It will be interesting to see if the accumulator is capable of holding any charge at all.


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## Vaurien

mel said:


> Congratualtions Paul TTIWWP as soon as!
> 
> 
> 
> 
> 
> 
> 
> :yahoo: :tongue2: :thumbup:
> 
> A pictorial tutorial on the restoration would be "just wunnerful" :yes:


Congratulations!

We were all wishing for this happy end!







:russian: :yahoo: :thumbup:


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## Robin S

Now we will never know what the open market would have valued it at.

Sure i'm not the only one that would have been passively watching with interest.


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## Mechanical Alarm

Paul do you ever let an auction go to conclusion and are your resources infinite??

OK, maybe the last part of that question was a little inappropriate... Congrats - Really!

*Also..., Everyone assumes you will do a restoration. I am of the firm belief that only the internals should be touched to get it back up to snuff. There is a lot to be said for originality. It's not like this thing is a mess!*


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## Silver Hawk

Mechanical Alarm said:


> Paul do you ever let an auction go to conclusion and are your resources infinite??
> 
> OK, maybe the last part of that question was a little inappropriate... Congrats - Really!


I think the first part is inappropriate as well.


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## mel

All we will ever know is it must have been more than the lowest possible ebay reserve :lol:

It's enough for me to know it has passed into the hands of the top leccy guru in the world, and will be loved, and stroked, and polished and cleaned, and loved, and might even be made to work, and loved, and stroked, and polished - - - - h34r:

OCD? Naaah!

:notworthy:


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## Silver Hawk

mel said:


> All we will ever know is it must have been more than the lowest possible ebay reserve :lol:
> 
> It's enough for me to know it has passed into the hands of the top leccy guru in the world, and will be loved, and stroked, and polished and cleaned, and loved, and might even be made to work, and loved, and stroked, and polished - - - - h34r:
> 
> OCD? Naaah!
> 
> :notworthy:


Thanks Mel. I have no idea what the buyer's reserve was but we reached a mutually agreeable price and the deal was done...so I guess that must have been higher than his reserve. Sometimes you win, sometimes you loose: 4-5 years ago, I tried to buy an Omega Speedsonic and made an offer to the seller of Â£500...seller turned this down and let the auction run to completion....I got it for Â£250 .

The watched tuned up today....accumulator voltage 0.037 volts....somewhat short of the 1.5 volts needed to drive the watch :lol:. I'm charging it as I type and will see what I can get it up to...and how long it will hold the charge. Photos tomorrow hopefully.


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## Silver Hawk

Charged up the accumulator for 20 hours and it read 1.402 volts at the end of the charge. After disconnecting and leaving for another 4 hours it had settled at 1.358 volts and wasn't falling further, so time to try it out! :yes:

Some photos:

A fairly standard Landeron 4750 although there are a couple of minor difference compared to others; I think this just reflects the fact that these accumulator versions were the very earliest of the Swiss electric movements. Some patina on the dial which doesn't worry me at all.



















Components of the case back to hold the accumulator:




























[more]


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## Silver Hawk

Case details with the original dummy crown covering the charging point:



















Assembled watch running well....but for how long on a single charge? :huh:


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## dowsing

I'm glad it's gone to a good home. I really like the look of it. Nicely retro, comic book lightening bolts, stylish face and case without looking over the top.


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## Who. Me?

Nice one Paul.

Bet you're relieved that it charged. What is the alternative if the accumulator dies? Can you get rechargeable cells in that size?


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## Mechanical Alarm

Silver Hawk said:


> Mechanical Alarm said:
> 
> 
> 
> Paul do you ever let an auction go to conclusion and are your resources infinite??
> 
> OK, maybe the last part of that question was a little inappropriate... Congrats - Really!
> 
> 
> 
> I think the first part is inappropriate as well.
Click to expand...

From Post #15: *Also..., Everyone assumes you will do a restoration. I am of the firm belief that only the internals should be touched to get it back up to snuff. There is a lot to be said for originality. It's not like this thing is a mess!*

It looks like you chose to disregard the last part of my comment, but It sounds like you are leaning more this direction.

I don't mean to step on any toes (well, maybe once or twice - but not this time) and it seems like there are about 4-5 people on here that are Golden and you do not dare say a word against them or the entire society will get you. I really was just joking. It seems that if you don't put a smiley face after a comment - your out for war and you can not possibly be joking or goofing with someone. I formally apologize for any hurt feelings as you have helped me out tremendously in the past and many others on here.

Friends...??

Robert (The Old Toe-Stepper)


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## Silver Hawk

Who. Me? said:


> Nice one Paul.
> 
> Bet you're relieved that it charged. What is the alternative if the accumulator dies? Can you get rechargeable cells in that size?


Not sure Andy, although Leclanche are still making capacitors. If it hadn't worked, I guess I could have bought one of the smaller ones that are used in Seiko Kinetics and made the appropriate adaptors.



Mechanical Alarm said:


> Friends...??


Of course.


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## handlehall

Any Idea how long it was expected to run for from one charge when it was new?


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## Silver Hawk

handlehall said:


> Any Idea how long it was expected to run for from one charge when it was new?


Not sure...I need to find out from my contact who has three of these watches. One of his is still able to power a watch for 3 weeks on one charge...but when new, it must have been much longer I imagine. The photos below are of his original charger:


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## mel

Great work already Paul! What sort of connector is used to charge it? Could you fudge up a wee solar panel, (from say one of those garden solar lights) and charge it up with that?

Although there's something "Special" about the idea of a standard 1.5 v battery doing the work! :yes:

And it's very clean, wonder if the original owner thought it was just too fiddly to recharge it and simply put it away forgotten all this time. Of course, the cell is labelled as 80mAh, if you can measure or work out the power draw under load, you should have a maximum (as new condition) runtime with a bit of division. Again, I wonder if the accumulator will improve after a few cycles of charge and discharge, I've seen that happen as well after a long period of disuse.


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## martinus_scriblerus

You know I was the first (and only) bidder on this one when it was listed on ebay. Then the auction ended.

I e-mailed the seller to ask what happened to the auction. Now I know!

I'm glad you got the seller to "sell it now" to you Paul.


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## Silver Hawk

martinus_scriblerus said:


> You know I was the first (and only) bidder on this one when it was listed on ebay. Then the auction ended.


Whoops! Sorry Dave but at least you'll be able to see it in the flesh in August. :thumbsup:



mel said:


> Of course, the cell is labelled as 80mAh, if you can measure or work out the power draw under load, you should have a maximum (as new condition) runtime with a bit of division.


Mel, I'm an idiot! I went back and checked my L4750 Service Sheets...and there is was...info on the accumulator version and a diagram of my watch with same case design. So check my maths:

Cell is 80mAh = 80,000uAh

Movement draws 15uA

80,000 / 15 = 5333 hours = 222 days = 7.5 months

Which sort of ties in with the recommendation to charge every 6 months; it also says a fully charged accumulation is 1.4v, so my 1.36v after a small charge is pretty good!


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## mel

Always glad to be of service Paul :lol:

At a pure guess, with a tiddle of maths, I'd think you might get as much as 8 weeks out of a charge from your start voltage that the cell is charging up to. Holding up is the imponderable factor, my guess is assuming a constant power draw and guessing at the terminal voltage whence the watch will cease to work.

Great Stuff!


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## Drum2000

Fantastic case design, gorgeous dial layout and colour not to mention rechargeable - a marvel of engineering. :thumbsup:


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## harryblakes7

Looks great Paul, looking at the movement the balance looks quite large and thin so presumably it is pretty accurate, just wondered how the timekeeping was..........


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## Silver Hawk

mel said:


> At a pure guess, with a tiddle of maths, I'd think you might get as much as 8 *weeks* out of a charge from your start voltage that the cell is charging up to.


Mel, where did you get the figure of 8 *weeks* from? I calculate more like 7 *months*...which seems to tie in with the ESA service sheet.



Drum2000 said:


> Fantastic case design, gorgeous dial layout and colour not to mention rechargeable - a marvel of engineering. :thumbsup:


Drum, I'm not sure the dial colour is how it started life. I think it has darkened considerable over the last 50 years....as I have :lol:.



harryblakes7 said:


> Looks great Paul, looking at the movement the balance looks quite large and thin so presumably it is pretty accurate, just wondered how the timekeeping was..........


Landeron 4750 based watches can be pretty good time keepers...and very robust....but thirsty on the juice.


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## mel

Paul, I was extrapolating an "old" cell - Keyrice, it's nearly as old as me, and whether or not it's capable of holding charge for any length of time. If you could get your hands on an 80mAh* new *cell or equivalent, I've no doubt it will easily run for about 5 to 6 months at the current draw you quote, can you find out what technology the cell uses, i.e. the components, I might have still a reference from work days (lost in the mists of time now :lol: ) that I could give you a ball park figure of what to expect at the approximate age of the cell.

We used a chart to determine different cell life and charge capacity depending on the composition of the clls, and it may be up in the loft.


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## Silver Hawk

Silver Hawk said:


> mel said:
> 
> 
> 
> At a pure guess, with a tiddle of maths, I'd think you might get as much as 8 *weeks* out of a charge from your start voltage that the cell is charging up to.
> 
> 
> 
> Mel, where did you get the figure of 8 *weeks* from? I calculate more like 7 *months*...which seems to tie in with the ESA service sheet.
Click to expand...

Mel, it ran for 7 weeks on the small charge I gave it overnight from a 344 battery :thumbsup:. My colleague thought this was impressive for such an old cell but advises me that if we charge the LÃ©clanchÃ© cell correctly with regulated current and well as voltage, we should be able to greatly improve on this. I'll give you an update, hopefully.

And just to prove watches really are like London Buses, I bought a second Landeron accumulator watch only a few weeks after the first, having not seen any for sale for the previous 10 years :no:. It is missing the LÃ©clanchÃ© cell unfortunately but the movement, case, dial and hands are in great condition --- makes me wonder if the brown dial on the first example really ought to be white like the second one. The movement in this second one is a 4751 rather than the more common 4750, so that is an additional plus point:


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## mel

Excellentay Paul! Love the calibre on the dial signature - makes life easier :yes:

I'd agree about setting up a definite charge regime, we had very old Leclanche type cells running for many years in the leccy board, but on continually monitored charge regimes keeping them charged and recycled and charged etc all the time. They were (at that time) used as back-ups in the cases of power failure to the mains, to enable remote switching controls to sub stations and exchange points. Mind, they were a tad large for your watch, about 9 inches square and 12 inches tall, packing a fair punch current wise. :notworthy:


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## azimuth_pl

hi Paul, good to see that you got this beauty after all. I don't recall exactly but I think your funds were low when I sent you that link 

the seller mentioned that the 4750 was from a Swiss watch school where students trained so this ESA branded piece must have been given by ESA directly to this school for students to learn.


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## ketiljo

Sorry for waking up an old post. I found this by chance today:










(sellers picture)

The original cell is missing, but it looks like it's in good shape.I'm pretty chuffed!

It has the same brownish dial as Paul's.

cheers,

Ketil


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## Silver Hawk

ketiljo said:


> Sorry for waking up an old post.


No need to apologise! Well done on grabbing one of these; you rarely see them as I'm sure you know. Your dial looks better than mine.

Interesting that the dummy crown is still present on yours and mine; I would have expected these to have become lost many years ago, although I think I read somewhere that the watch was sold with a spare one.

:thumbsup:


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## mel

So, all is not lost - Eh? Maybe I *will *find another Dorado one day at a car boot sale for a fiver :lol:

Congratulations on picking up (and thus preserving) another piece of Electric Horological History :yes:

Are you going to try and get it working?


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## ketiljo

mel said:


> So, all is not lost - Eh? Maybe I *will *find another Dorado one day at a car boot sale for a fiver :lol:
> 
> Congratulations on picking up (and thus preserving) another piece of Electric Horological History :yes:
> 
> Are you going to try and get it working?


Thanks. It's running already since someone at some point has made a spacer to use a ordinary cell. I'm going to pick it up from the post office today, I'll post some pictures.


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