Need gossen Lunapro light meter battery adapter: My ancient Gossen Lunapro light meter used the 1.35V mercury button batteries (2)but they are no longer made. Gossen made a voltage...

lightyear

My ancient Gossen Lunapro light meter used the 1.35V mercury button batteries (2)but they are no longer made. Gossen made a voltage reducing adapter(no longer sold) which accepted the LR44 alkaline 1.5V button cells and reduced voltage to 1.35Volts . Does anyone have an adapter or meter that has one in it. The Wein 1.4V hearing aid battery works but once in place wears out quickly , even if not used. Thanks.
Stan

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

lightyear wrote:

My ancient Gossen Lunapro light meter used the 1.35V mercury button batteries (2)but they are no longer made. Gossen made a voltage reducing adapter(no longer sold) which accepted the LR44 alkaline 1.5V button cells and reduced voltage to 1.35Volts . Does anyone have an adapter or meter that has one in it. The Wein 1.4V hearing aid battery works but once in place wears out quickly , even if not used. Thanks.
Stan

https://www.bhphotovideo.com/c/search?q=Wein%20MRB625%20Cell%201.35v%20Zinc-Air%20Battery%20&sts=ma

Manglesphoto Loc: 70 miles south of St.Louis

lightyear wrote:

My ancient Gossen Lunapro light meter used the 1.35V mercury button batteries (2)but they are no longer made. Gossen made a voltage reducing adapter(no longer sold) which accepted the LR44 alkaline 1.5V button cells and reduced voltage to 1.35Volts . Does anyone have an adapter or meter that has one in it. The Wein 1.4V hearing aid battery works but once in place wears out quickly , even if not used. Thanks.
Stan

Take the battery out when you're not using it!! which is a good idea with any battery operated tool or appliance.

edwdickinson Loc: Ardmore PA

lightyear wrote:

My ancient Gossen Lunapro light meter used the 1.35V mercury button batteries (2)but they are no longer made. Gossen made a voltage reducing adapter(no longer sold) which accepted the LR44 alkaline 1.5V button cells and reduced voltage to 1.35Volts . Does anyone have an adapter or meter that has one in it. The Wein 1.4V hearing aid battery works but once in place wears out quickly , even if not used. Thanks.
Stan

When did the Lunapro use button batteries? Mine uses a 9 volt battery and is 40+ years old.

User ID

edwdickinson wrote:

When did the Lunapro use button batteries? Mine uses a 9 volt battery and is 40+ years old.

More than 40+ years ago. LunaPro dates to the 1960s. It was the first significant CdS cell exposure meter. Yours might be the SBC version.

edwdickinson Loc: Ardmore PA

User ID wrote:

More than 40+ years ago. LunaPro dates to the 1960s. It was the first significant CdS cell exposure meter. Yours might be the SBC version.

It is, moved to this one in 1979.

lightyear

"take the battery out" advice does not apply to the Wein battery. In its airtight sealed plastic bubble the battery is stable and does not 'run down' but once it is removed from the bubble and exposed to air it begins to run down, and continues to deplete- even if put back in ( if it could be done)in an airtight bottle. The alkaline or lithium batteries only deplete if used.

pendennis

Here's the link to the seller of the MR-9 adapter. I believe your Gossen takes two.

However, before you take this step (the MR-9's are @ $40), consider buying a newer, used Gossen Luna Pro SBC. It uses 9 volt transistor batteries, and they can be had for less than $80.

https://shop.criscam.com/products/mr-9-mercury-battery-adapter

StanMac Loc: Tennessee

I suggest that you contact Zacks Camera Repair and inquire if he can add a schottke diode to the circuit and recalibrate the meter. He performed that service for me on a Sekonic L-248 meter. The only issue may be that the Gossen uses two 1.35vdc batteries whereas the Sekonic used only one. Michael Zack will be able to advise you if he can make that adjustment. The Gossen battery adapters are an extremely rare item. I was lucky to buy a Luna Six that had one in it. My other Gossen meter I had recalibrated by Quality Light Metric before it closed its doors. As someone mentioned above, you might try to locate a Gossen LunaPro SBC meter which uses the common 9 volt battery.

The other easier to implement fix is to determine how much higher the meter reads with a 1.5vdc battery by comparing it a reading with one of your cameras and adjust the ISO of the meter to match the camera reading. Note the difference in stops and adjust the meter’s ISO accordingly in each future use of the meter for the film you are using.

Stan

Alafoto Loc: Montgomery, AL

lightyear wrote:

"take the battery out" advice does not apply to the Wein battery. In its airtight sealed plastic bubble the battery is stable and does not 'run down' but once it is removed from the bubble and exposed to air it begins to run down, and continues to deplete- even if put back in ( if it could be done)in an airtight bottle. The alkaline or lithium batteries only deplete if used.

I read somewhere that to prolong the life of this kind of battery one should put tape over the tiny "breathing hole" in the battery after removing it from your device.

lightyear

The tape will diminish the air supply and prolong life, but not enough. Some air leaks in.

User ID

I use commonly available silver oxide batteries. I use simple shims to hold them in place. If the metering needs compensation I compensate. Its that simple. It all works about 90% of the time. When it doesnt work I junk the item. Theres nothing that ever ran on mercury button batteries that cant be painlessly junked if my simple crude measures dont salvage it.

rmalarz Loc: Tempe, Arizona

The only way to go is with an MR-9 adapter. These contain a voltage regulator which drops the 1.5V of a 386 battery to 1.35. I use these in my Nikon F, Weston Ranger 9, and several other older photograph equipment. They work very well and the batteries last a considerably longer time. My F batteries I change every New Year just to change them. These are not inexpensive but well worth the money.
https://shop.criscam.com/collections/mercury-battery-adapters/products/mr-9-mercury-battery-adapter
https://www.35mmc.com/14/01/2015/mr-9-battery-adapter/

Beware!!! There are a number of adapters that look like the MR-9 but do not contain the voltage regulator circuitry. These will NOT drop the voltage.
--Bob

lightyear wrote:

My ancient Gossen Lunapro light meter used the 1.35V mercury button batteries (2)but they are no longer made. Gossen made a voltage reducing adapter(no longer sold) which accepted the LR44 alkaline 1.5V button cells and reduced voltage to 1.35Volts . Does anyone have an adapter or meter that has one in it. The Wein 1.4V hearing aid battery works but once in place wears out quickly , even if not used. Thanks.
Stan

pendennis

rmalarz wrote:

The only way to go is with an MR-9 adapter. These ... (show quote)

See my earlier post. The Gossen Luna Pro takes (2) MR-9 adapters @ $40/each. For less than $80, you can get a newer, more accurate Luna Pro SBC. Unless there's a sentimental reason to hold on to the old CDS Luna Pro, it's not worth chasing down options.

rmalarz Loc: Tempe, Arizona

Dennis, as with a lot of my "suggestion" posts, I simply provided a solution to the issue and one that I personally know works. I leave it up to the OP to make appropriate decisions for themselves.
--Bob

pendennis wrote:

See my earlier post. The Gossen Luna Pro takes (2) MR-9 adapters @ $40/each. For less than $80, you can get a newer, more accurate Luna Pro SBC. Unless there's a sentimental reason to hold on to the old CDS Luna Pro, it's not worth chasing down options.