Leicaflex SL2 battery solution

[Ivar B]

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I wonder if anyone has any recent update on this. I know the Wein Cell works, but it has a short life time. I bought some battery adapters on eBay:

2PC MR-9 Batterie Adapter Fit For Film Camera & Exposure Meter PX625 MR9 PX13 GE | eBay

These could be used with new PX 675 hearing aid batteries, using the same technology as the Wein Cells.

However, the adapter appears to bee too thick - with the adapter in place the battery cover can not be screwed on. Without adapter at all, the light meter responds fine, and this problem did not arise on the SL, only on SL2.

Does anyone know of an adapter which works well on the SL2?

 

[TomB_tx]

The real MR9 does have a diode circuit to provide correct voltage. It appears that the one in your link simply provides the outer dimensions of the old battery.

Even a real MR9 will be too thick using common cells that are thicker than the required 386 cell. I once sent a camera to DAG with an MR9 and he pointed out that the battery (LR44?) I tried with it was too thick - it needed a 386 cell.

[masjah]

4 hours ago, TomB_tx said:

The real MR9 does have a diode circuit to provide correct voltage. It appears that the one in your link simply provides the outer dimensions of the old battery.

Even a real MR9 will be too thick using common cells that are thicker than the required 386 cell. I once sent a camera to DAG with an MR9 and he pointed out that the battery (LR44?) I tried with it was too thick - it needed a 386 cell.

The diode is to drop the voltage of a silver oxide cell to that of the original mercury cell. A Wein cell is already at the correct voltage. So if this "adapter" says to use a hearing aid battery, it may well be simply for changing dimensions - a bit of a con really.

[Ivar B]

13 hours ago, TomB_tx said:

The real MR9 does have a diode circuit to provide correct voltage. It appears that the one in your link simply provides the outer dimensions of the old battery.

Even a real MR9 will be too thick using common cells that are thicker than the required 386 cell. I once sent a camera to DAG with an MR9 and he pointed out that the battery (LR44?) I tried with it was too thick - it needed a 386 cell.

Apparently the hearing aid batteries lose some voltage quickly and in practice work well, but I will try out a 386 cell. Many thanks - useful advice. 

[nitroplait]

3 hours ago, Ivar B said:

Apparently the hearing aid batteries lose some voltage quickly and in practice work well, but I will try out a 386 cell. Many thanks - useful advice. 

No - yours are dumb adapters made for Zinc-air cells - don't put 386 in them.

A 386 is a silver oxide 1.55V cell and will not give the correct voltage unless you have a "real" MR-9 adapter (see photo below).

Those brass adapters are made with the usual lack of QC typical for low priced Chinese products. If you have the tools, you can try to modify it, make your own or try to buy from another vendor. It is just a matter of luck - mine happens to work.

Zinck-air cells are very easy to find and cost very little, and they do exactly the same as the overpriced Wein cells. I usually get 4-6 months out of a battery and buy them on Amazon for less than $2 for a pack of 6. They are also available in most pharmacies.

386 cells are a little more difficult to find and cost a good deal more.

Left is a real MR-9 adapter with a circuit made by Kanto Camera in Tokyo (and associated 386 battery for illustration. Right are the dumb fake MR-9 that only works with the Zinc-air hearing aid batteries shown.

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[Ivar B]

3 hours ago, nitroplait said:

No - yours are dumb adapters made for Zinc-air cells - don't put 386 in them.

A 386 is a silver oxide 1.55V cell and will not give the correct voltage unless you have a "real" MR-9 adapter (see photo below).

Those brass adapters are made with the usual lack of QC typical for low priced Chinese products. If you have the tools, you can try to modify it, make your own or try to buy from another vendor. It is just a matter of luck - mine happens to work.

Zinck-air cells are very easy to find and cost very little, and they do exactly the same as the overpriced Wein cells. I usually get 4-6 months out of a battery and buy them on Amazon for less than $2 for a pack of 6. They are also available in most pharmacies.

386 cells are a little more difficult to find and cost a good deal more.

Left is a real MR-9 adapter with a circuit made by Kanto Camera in Tokyo (and associated 386 battery for illustration. Right are the dumb fake MR-9 that only works with the Zinc-air hearing aid batteries shown.

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Simply register for free here – We are always happy to welcome new members!

 

I saw the real MR9 adapter on eBay I think. It fits the SL2 and is not too thick for the battery well?

 

[TomB_tx]

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I use a real MR9 with 386 on my SL2

[nitroplait]

Not owning an SL2, I can't give you any guarantees.

Both my MR-9 and the dumb brass adapters fits into my Leicameter, Nikon F (photomic), Gossen meter and other devices without problems - and they work equally well.

If you buy a real MR-9 I think you are best served by getting a brand name such as C.R.I.S. or Kanto Camera (they are not cheap) - otherwise you just risk getting some Chinese poor QC trash again.

I personally think the dumb brass adapter and cheap zinc-air hearing aid cells is the cheapest and most convenient solution (easier to find batteries and they are cheap). But it requires that you can find an adapter that fits - of course.

[nitroplait]

By the way - I just remembered. Before Brexit, I purchased a dumb brass adapters from Milly's Cameras in the UK. It was another adapter for my Pentax Spotmeter but it was well machined.

They also sell the PX625 dumb brass adapters and they explicitly mentions compatibility with SL2.

https://cameramill.co.uk/product/camera-battery-adapter-mr9-625a-mrb625-px625-epx625-px13/

Just a heads up.

Edited August 15, 2022 by nitroplait

[TomB_tx]

BTW - The SL2 has two battery compartments: one for the meter and one for a VF light to illuminate the meter needle in dark settings. For the VF light (front of camera ) just use a 625A alkaline cell - much cheaper than an MR9.

There was someone (Jon Goodman?) in the USA that took apart the Alkaline 625A calls and made adapters out of them to hold a hearing aid battery. These were correct thickness, due to the thin shell of the 625A battery. 

I did a search and found this:

https://vintagelens.nl/2018/02/19/easy-battery-substitute-px625-mercury-cell-om1/

[Joop van Heijgen]

The MR-9 adapter needs a SR44 and NOT a LR44. I use it on my Leicaflex SL and it works fine! 

Edited August 16, 2022 by Joop van Heijgen

[masjah]

2 hours ago, Joop van Heijgen said:

The MR-9 adapter needs a SR44 and NOT a LR44. I use it on my Leicaflex SL and it works fine! 

Exactly!!!  You need to use a silver oxide cell, in order (a) to get exactly the right initial voltage prior to it being dropped down by the adapter diode to the original mercury cell level, and, just as importantly, you need a cell type whose voltage remains constant until the cell is actually exhausted.

(The metering electronics of older cameras rely for their accuracy in turn on the voltage accuracy of their power cell. Most non-silver cells have a falling voltage characteristic as the cell is discharged, which is no good at all.)

 

[nitroplait]

Zinc-air has an excellent discharge profile and is therefore a good alternative to the MR-9 + SR43.

Although often marked 1.4 or 1.45v, all those Zinc Air I have tested measured 1.36-1.37V.

[TLCLeicaM3]

"Zinc-air has an excellent discharge profile"

Add to that "excellent" at discharging their corrosive chemical ! - Check out the two links below :

 

I adjust ALL 1.35V meters as they were intended. I recommend using the very stable "Silver" oxide battery with a 

highly recommended step-down adapter. <<< click Using a 1.5V SILVER battery converted to 1.35V - 

My comments on battery choices are here: Silver, Alkaline & Zinc-Air batteries <<< click & scroll down 8 spots.

[nitroplait]

On 8/18/2022 at 4:50 PM, TLCLeicaM3 said:

"Zinc-air has an excellent discharge profile"

Add to that "excellent" at discharging their corrosive chemical ! - Check out the two links below :

 

I adjust ALL 1.35V meters as they were intended. I recommend using the very stable "Silver" oxide battery with a 

highly recommended step-down adapter. <<< click Using a 1.5V SILVER battery converted to 1.35V - 

My comments on battery choices are here: Silver, Alkaline & Zinc-Air batteries <<< click & scroll down 8 spots.

Post #8 is written by Gus Lazzari. and if that is you, sir, then let me just say that I miss you over at photo.net, and that the offensive moderator that deleted your thoughtful post back then, isn't moderator any more.

I hope you will return. I miss your thoughtful advice 🙂

I agree with you that one have to be very observant when using zinc-air cells.

Take them out when not in use! 
It is a very important point that I should have added. I often recommend regular Zinc_Air because I think Wein Cells are a ripoff.

Zinc-air is zinc-air, but Yes, be aware that they sweat if you leave them beyond their life.

If one is not attentive or a sloppy person, then: absolutely - use the MR-9 converter with a Silver Oxide battery.

I might add; if you have a camera that uses 2x 1.5V cells (Like my Leica R3, M6 and many others) Dont use LR batteries, use SR or even better: one CR1/3N (3V). Not only does an Lithium battery have an amazing shelf life, it is also very safe with a stable discharge curve (at least that is my experience).

Edited August 19, 2022 by nitroplait