MR-9 Battery Adapter

[Disconnekt]

I have a MR-9 adapter for my Sears TLS, the Duracell 386 battery I use in it goes in & out fine

 

[MattKing]

Last time I checked, "A76" batteries (I use the term generically) were available in silver oxide -- just as the 386 is available in alkaline. Apparently, I'm not the only one: using them:

MR-9 Adapter 1.55V to 1.35V

Has anyone had any experience with this adapter? I recently purchased one and prior to install it in one of my cameras I tried to measure the voltage with a voltimeter: But I cannot see such voltage reduction. Looking carefully at the manufacturer site...

www.photrio.com

Sorry, I came from a time of purity, where the mighty silver oxide batteries were designated MS76, and A76 was limited to their lowly Alkaline brethren.
It is hard to break old habits

 

[BrianShaw]

This is why it’s often a challenging conversation about batteries. There isn’t always nomenclature commonality between brands.

One “Rosetta Stone”:

https://www.grithappens.com/mediadata/manufpdfs/duracell-2_1320692144.pdf

There are many more. The easiest to understand seem to be those that are less complete.

 

[xkaes]

I'm sure the "A" in A76 means "alkaline" and the "S" in S76 means "silver", but most people/companies don't call the "76" batteries "76" anymore, anyway. They are apparently called "G13", "R44", "357", etc.

The "386" batteries are the same width as the "76", but about 1mm thinner -- which should not make them more difficult to remove from the adapter, but I've seen a lot of "copy-cap" adapters for sale which are not really copy-cats at all because they don't change the voltage at all -- even though some claim to. They simply physically mimic a 625 battery -- which might work fine in some circumstances. Some have a small hole in the bottom which would made removal of the "76" or "386" battery very easy.

 

[BrianShaw]

The only problem I’ve ever experienced is with the height difference between the 357 and 386 due to that 1mm thickness difference is fitment of the battery cap. Other than that, both fit the adapters and work the same.

 

[xkaes]

I've got one meter that has that problem -- mainly because it requires TWO 625 batteries in a stack, so it's TWO millimeters thicker with the "76" batteries in adapters. So I use the thinner 386.

 

[chuckroast]

You wouldn't normally want to use an A76 battery in most of these. You would want to use a silver oxide battery in the adapters that drop the voltage, or a hearing aid/zinc air battery in the ones that don't.

100%. You do not, not, not want alkaline batteries anywhere near a metering circuit because they die slowly and incrementally give you incorrect readings. You want a sliver oxide (the zinc air ones work, but they have a dreadfully short life).

If your meter has been recalibrated for the new higher voltage, there is a hack that may make it possible to avoid even a plain - non voltage dropping - battery adapter. I have not yet tried it, but there is a way (it is alleged) to use an large o-ring to hold an LR44 or similar battery in a compartment made for the old PX625 mercury batteries.

 

[BrianShaw]

I've got one meter that has that problem -- mainly because it requires TWO 625 batteries in a stack, so it's TWO millimeters thicker with the "76" batteries in adapters. So I use the thinner 386.

Yep. The adapters I use most, from Criscam, specify the thinner battery.

 

[MattKing]

100%. You do not, not, not want alkaline batteries anywhere near a metering circuit because they die slowly and incrementally give you incorrect readings. You want a sliver oxide (the zinc air ones work, but they have a dreadfully short life).

There are a few cameras - including some Pentax models - that employ bridge circuits that are relatively voltage independent. But if your meter isn't in that category, this is correct.
The best source for zinc air batteries is someplace that sells hearing aid batteries in quantity. Costco is a good option, in my experience.

 

[chuckroast]

There are a few cameras - including some Pentax models - that employ bridge circuits that are relatively voltage independent. But if your meter isn't in that category, this is correct.
The best source for zinc air batteries is someplace that sells hearing aid batteries in quantity. Costco is a good option, in my experience.

Yes, but they don't make them in the 625 form factor, I don't think, which is what my meters and cameras want. I have a few S625 batteries left, but they are no longer made so far as I am aware.

 

[wiltw]

Yes, but they don't make them in the 625 form factor, I don't think, which is what my meters and cameras want. I have a few S625 batteries left, but they are no longer made so far as I am aware.

The PX-625A alkaline is same size as PX-13 mercuric oxide, and cameras like the Pentax 1000 could tolerate Voltage higher than 1.35V without metering error; they are still widely available

Google Search

 

[axestrata]

This is why it’s often a challenging conversation about batteries. There isn’t always nomenclature commonality between brands.

One “Rosetta Stone”:

https://www.grithappens.com/mediadata/manufpdfs/duracell-2_1320692144.pdf

There are many more. The easiest to understand seem to be those that are less complete.

I agree. And it gets even more frustrating when trying to purchase online and the listing of the battery for sale is mislabeled or misrepresented.

 

[Laurent]

I'm sure the "A" in A76 means "alkaline" and the "S" in S76 means "silver", but most people/companies don't call the "76" batteries "76" anymore, anyway. They are apparently called "G13", "R44", "357", etc.

The "386" batteries are the same width as the "76", but about 1mm thinner -- which should not make them more difficult to remove from the adapter, but I've seen a lot of "copy-cap" adapters for sale which are not really copy-cats at all because they don't change the voltage at all -- even though some claim to. They simply physically mimic a 625 battery -- which might work fine in some circumstances. Some have a small hole in the bottom which would made removal of the "76" or "386" battery very easy.

View attachment 391464

The Canon EF works pretty fine with these, as it regulates its' own tension. I could even make then myself with a scrap of brass. Next step would be to adapt a proper regulator in the F1s

 

[reddesert]

Absolute statements are often overstatements. It's not technically correct to use an alkaline battery in a camera meter not designed to take it, but many people have used alkaline batteries in such cameras for a long time before the internet declared it was verboten, and managed ok. It depends on the camera, and on your willingness to compare it occasionally to another light meter (and sunny 16) to make sure it's not going off and works over the brightness range you need it for, and replace the battery before it gets really low. Of course it also helps if you're shooting B&W or color negative film and have more latitude than slide film.

For ex, I used a PX625A alkaline in my Canonet QL17 for years and survived. I'm sure if you look at my negatives, they weren't all dead on within 1/3rd stop, but a Canonet's meter (non-TTL cell above the lens) is not a precision instrument even with the correct battery. The correct battery does not relieve you of thinking about the exposure.