Pentax Digital Spotmeter Battery

SodaAnt · Aug 23, 2023

The battery for the Pentax Digital Spotmeter comes in silver oxide, alkaline, and lithium versions.

Is any one of these preferred over the others? I’m more concerned about meter accuracy than battery life. Alkaline and lithium versions are much more common in local stores—I haven’t seen the silver oxide battery in a store in years.

BrianShaw · Aug 23, 2023

The manual specifies one six-volt silver oxide (#544 or equivelent) or 537 alkaline battery.

In meters I generally opt for silver oxide since they are long lasting and have a very flat discharge curve, theoretially making the meter more accurate as the end of battery life is encountered. It may be, though, that silver oxide in that size is no longer available.

In my area we have a chain called Batteries Plus. I've always found what I need there plus options, including good advise.

https://www.batteriesplus.com/?source=google&medium=search&campaign=ecommppc&gclid=Cj0KCQjw3JanBhCPARIsAJpXTx7Hrd3kYbBftXh4KU2gL4B_LxnJDFEihDdv9KeHrOc75uUKE0AnvD0aAml-EALw_wcB

MattKing · Aug 23, 2023

Alkaline batteries are more prone to leakage.
Usually silver oxide are easily obtained from internet sources, and I prefer them to alkaline.
In many cases, the equipment we use predates lithium batteries, which do have distinctly different characteristics, so I generally advise caution when considering substituting them for silver oxide in the older equipment.

SodaAnt · Aug 23, 2023

Amazon has two brands of silver oxide batteries in the 544 size: Camelion and Excell, neither of which I’ve heard of. All of the common brands (Energizer, Duracell, etc.) seem to be available in alkaline or lithium only.

Are these two brands okay to use in the meter?

BrianShaw · Aug 23, 2023

If I were to buy one, it would be the Excell, and I'd take it out of the meter when not using. Camelion is a much newer company that I just learned about via your post. Either is probably okay.

L Gebhardt · Aug 23, 2023

The Excell silver oxide work well in my Pentax Digital spot meters.

MattKing · Aug 23, 2023

I have some ~+5 year old Camelion silver oxide batteries of that type that are just now showing their age.
I think I bought them through eBay.

Chan Tran · Aug 23, 2023

Silver Oxide would last longer than the Alkaline and is not likely to leak. I think the Lithium last longest not being used but if used it doesn't last as long as the Silver Oxide. So I would choose the Silver Oxide but a good meter should not have different readings due to battery voltage.

BrianShaw · Aug 23, 2023

MattKing said:
I have some ~+5 year old Camelion silver oxide batteries of that type that are just now showing their age.
I think I bought them through eBay.

Five years in use, or five years in storage?

MattKing · Aug 23, 2023

BrianShaw said:
Five years in use, or five years in storage?

At least 5 years, probably more.
I bought a box of 10.
I've been using them up, one by one. I have/had more than one piece of equipment that used them. I think I have one or two left.
The last couple of them haven't lasted as long as the earlier ones.

SodaAnt · Aug 23, 2023

Interesting tidbit: the most common use for this battery is in dog bark collars.

MattKing · Aug 23, 2023

SodaAnt said:
Interesting tidbit: the most common use for this battery is in dog bark collars.

Mostly the alkaline ones though.
In its original, silver oxide incarnation of PX-28, it helped take the photographic world by storm in the Canon AE-1.
And it powers all the Mamiya 645 manual focus cameras.

BrianShaw · Aug 23, 2023

MattKing said:
At least 5 years, probably more.
I bought a box of 10.
I've been using them up, one by one. I have/had more than one piece of equipment that used them. I think I have one or two left.
The last couple of them haven't lasted as long as the earlier ones.

That makes a lot of sense. At 5 years, the shelf life is probably near or already exceeded. There is also an increased risk of leakage with battery age. I tend to not buy batteries in bulk anymore because of that. Having a Batteries Plus store within walking distance makes small-quantity battery buys much easier.

Sirius Glass · Aug 23, 2023

I use Silver Oxide in my Pentax Digital Spot Meter.

Ian David · Aug 23, 2023

The Exell silver oxide version works well in a couple of my meters that use that style of battery. B&H stocks them (Exell S28PX)

SodaAnt · Aug 24, 2023

BrianShaw said:
In my area we have a chain called Batteries Plus. I've always found what I need there plus options, including good advise.

There’s one near me. I stopped there on the way home and the only battery they had in this form factor was a DuraHell A544.

I’ve not had much luck with DuraHell batteries. It’s not a matter of if they leak, but when. It’ll tide me over until the silver oxide battery I ordered from Amazon arrives.

Dirb9 · Aug 25, 2023

You can just buy a bunch of SR44 and stack them in the battery compartment, the spring in the Digital Spotmeter is long enough that it doesn't need the button top of a 4SR44 battery. 4x SR44 batteries are about half the price of the packaged 4SR44 ones from Camelion or Excell.

eli griggs · Nov 8, 2023

Hands down my choice, Silver Cells, for all my small, button cell battery operated kit.

SodaAnt · Dec 5, 2023

I did end up ordering some silver oxide cells from B&H and use one in the meter and a spare in the camera bag.

jk0592 · Dec 5, 2023

That's what I use, and I keep a coin with the spare, to replace in field if necessary.

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