Battery Question

[reddesert]

Ah, I see, the first chart clearly says AA in the caption and I glanced over that. The chart for the Ansmann button cell with a 22 Kohm resistor is at a steady current of 68 microamps which is much like what a button cell probably sees.

Here's some specs from Maxell for silver oxide and alkaline button cell batteries (click on the Specs tab): https://biz.maxell.com/en/primary_batteries/sr_coin.html The SR44 has a nominal capacity of 165 mAh and nominal current supply of 200 microamps, and the LR44 has a capacity of 110 mAh and nominal current of 100 microamps, which supports the usual statement that silver oxides have about 1.5-2x the capacity of same-size alkalines. I suspect this is one reason why camera manufacturers specified the silver oxide and tell you not to use the alkaline, especially in electronic shutters - it's not going to hurt anything (other than the meter accuracy), but it will die sooner and they don't want the user to complain about dead batteries.

 

[wiltw]

Ah, I see, the first chart clearly says AA in the caption and I glanced over that. The chart for the Ansmann button cell with a 22 Kohm resistor is at a steady current of 68 microamps which is much like what a button cell probably sees.

Here's some specs from Maxell for silver oxide and alkaline button cell batteries (click on the Specs tab): https://biz.maxell.com/en/primary_batteries/sr_coin.html The SR44 has a nominal capacity of 165 mAh and nominal current supply of 200 microamps, and the LR44 has a capacity of 110 mAh and nominal current of 100 microamps, which supports the usual statement that silver oxides have about 1.5-2x the capacity of same-size alkalines. I suspect this is one reason why camera manufacturers specified the silver oxide and tell you not to use the alkaline, especially in electronic shutters - it's not going to hurt anything (other than the meter accuracy), but it will die sooner and they don't want the user to complain about dead batteries.

And alkaline button being above 1.35V for only 40% of its 100 microAmps when diode is used to drop to 1.35V, we have effective life of 40 microAmps alkaline vs. 200 microAmps silver oxide. No wonder OP has his observation of 'short life' alkalines.

 

[benjiboy]

That's a good question. As I understand it, older cameras had no voltage regulator so they relied on the constant voltage output of mercury batteries. Where PX-13 batteries are concerned, I have used MR-9 adapters with MS76 or 386 1.5 volt batteries. The Canon F-1/F-1n and FT series cameras which have been converted for use with 1.5 volt batteries all work well. The same us true for the converted Minolta SRT cameras. I use 625A batteries in them. I have plain adapters without voltage conversion and with certain cameras I can use 675 zinc-air hearing aid batteries. They don't last terribly long but work. A silver oxide 625 would be nice for some of the converted cameras.

The one exception in the Canon F series cameras in addition to the Original F1 and the Canon F1n is the Canon EF that has a built-in voltage regulator, that works perfectly with 2 PX 625 A batteries.