Re: Batteries

["M. Robson" <mrobson1@xxxxxxxxxxx>]

John Bercovitz wrote:
> 
> I'm looking in an old Burgess manual at the Hg 625R and
> it shows at a low drain, like 3 mA, the life to 1.2 V
> is 75 hours and the life to 0.9 V is 80 hours.  So at
> low drain, the voltage drops like a rock at the end.
> My recollection is that the R type depolarizer gives
> you a lower voltage (1.35 vs 1.40) but a stabler voltage
> but lower energy density.  Not too much on that subject in
> this manual.
> 
> I don't have any current stuff on silver cells and no curves.
> Just a listing of the voltage.  Fooling around last night,
> I found the silver and alkaline no load voltages of new
> cells at 70F was the same down to about 1 mV.
> 
> Anyone have some curves on silver?
> 
> Thanks,
> John

I've got a Radio Shack Enercell Battery Guidebook which has
data and curves on a variety of their batteries. The discharge
curve on the type 76 Silver (for photo use) is flat as a board.
The curve however was with very low current drain 242 microamps 
and a load of 6500 ohms. It drops to 0.9v at 820 hrs. It looks like
it maintains about 1.55 v. out beyond 700 hrs. I don't know how it
would behave in typical camera metering use though.

The text mentions hybrid silver oxide cells which use a KOH
electrolyte with a greater mix of manganese dioxide and reduced
silver oxide in the cathode which it says results in a more
sloping discharge curve for these cells.

Mark