# Need Some Advice On Battery Choice For A Hamilton Electric



## YouCantHaveTooManyWatches (Nov 28, 2010)

I have a 60's Hamilton Centaur and would like to know if anyone can advise me on the RIGHT choice of battery for it as it seems to eat batteries like they were going out of fashion and a I wonder whether I am either harbouring a bad batch of batteries or buying the wrong make of battery or maybe just using the wrong type?


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## jasonm (Nov 22, 2003)

Wrong type of movement maybe  I dont think they are particularly cell friendly ... How long do you get out of them?

What are you using?

How long have you had them?

Start point would be to buy a quality brand new one I would think........


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## Silver Hawk (Dec 2, 2003)

The Centaur should have a 505 movement in it...so it should take a 301 battery but make sure it is a make like Renata. 301s are a little tricky...not all manufacturers make them the same shape. An Energizer 301 for instance is no good, but a Renata 301 is. Also, make sure you mask off (insulate) most of the negative side of the battery except where the spring terminal touches it...they have a habit of shorting out on the body of the movement.


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## hamiltonelectric (Feb 27, 2010)

I don't know about the UK but here in the US we are receiving shipments with redesigned Renata 301 cells that are the same as the Energizers. In fact, ALL of the manufacturers have now changed their 301 batteries. There are no 301 batteries available that have the same shape as the originals.

The original design had a 'dimple' in the center of the bottom (negative) pole which nestled into a corresponding indentation in the pillar plate of the Model 505 movement. The modern ones have a flat bottom which will instantly short out against the pillar plate.

Even if you insulate the negative pole to prevent short-circuiting, there's another serious problem with the new ones: the edges are now the same thickness as the center, which was not the case originally. This results in excessive pressure being applied to the battery clamp, which can easily cause the delicate T-shaped end of the clamp to snap off.

This is becoming a serious headache since people see either an old battery or look up the proper battery and happily buy a 301, not realizing that today's 301s are not like yesterday's. I'm seeing an epidemic of broken battery clamps as a result.

The only viable option today is a 387S, which fits perfectly thanks to a plastic spacer ring. No extra insulating is needed. However the battery is smaller than the old 301 and will have a shorter lifespan. It should still last close to a year.


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## Silver Hawk (Dec 2, 2003)

hamiltonelectric said:


> I don't know about the UK but here in the US we are receiving shipments with redesigned Renata 301 cells that are the same as the Energizers.


Still getting the dimpled Renata 301 on this side of the pond. Maybe I'm using up old stock....there are not many movements that take a 301.


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## hamiltonelectric (Feb 27, 2010)

Definitely not the freshest stock, then. I got my first "redesigned" Renata 301s from Otto Frei Co. about 4 or 5 months ago. That's when I called to check on Panasonic, Sony, and all the others I hadn't used yet. The bad news was that they were all identical to Energizer.

I remember years ago having a discussion with an Energizer representative (when it was still called Eveready) about the redesign. He had contacted me after a customer complained about battery leakage from a new battery, and the customer referred him to me. I ended up sending him a 505 pillar plate and a sample of an old, dead 301. He acknowledged the problem but said that the corporate bosses had decided that it wasn't worth their worrying about. All of the modern watches that take a 301 easily accommodate a battery with a flat bottom and no dimple. The number of Hamilton 505s is so small that it's simply not a concern. That said, they reimbursed my customer for the total cost of my restoring his watch again.

I can completely understand the battery manufacturers' position; from their standpoint the 505 is a relic, just as the 500 when Eveready stopped making 201 batteries around 1990. But as I noted earlier, the problem is different. Anyone looking for a 201 will hit a brick wall. Anyone looking for a 301 will find one easily. They simply won't be aware that they're not made the same way as in the past. The net result is shorted batteries, possible leakage, and probable battery clamp breakage. I really wish they had just renumbered the altered 301s and called them something else entirely.


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