On Wednesday, 11 November 2020 at 20:36:34 UTC, Fredxx wrote:
On 11/11/2020 03:13:29, tabby wrote:
On Tuesday, 10 November 2020 11:10:41 UTC, Fredxx wrote:
On 10/11/2020 03:04:36, tabbypurr wrote:
On Monday, 9 November 2020 10:16:51 UTC, Martin Brown wrote:
On 08/11/2020 13:59, Fredxx wrote:
On 08/11/2020 13:42:21, Scott wrote:

My multimeter has a battery test facility that shows the
battery as good or bad (or on the margin). I understand a zinc
carbon battery has a voltage of 1.5 Volts and an alkaline
battery has a voltage of 1.2 Volts? How does it know the
difference between a very good alkaline battery and a very bad
zinc carbon battery?.

An alkaline battery also has a nominal o/c voltage of 1.5V

A good fresh alkaline can be as high as 1.6v open circuit.

They start off above 1.5v. 1.5v is only nominal.

A well used one can go as high as 1.8v under odd circumstances. I had
a couple do that earlier this year. They were well used then
recharged, and gave a strangely high output. No idea why, none of the
others did.

Most articles suggest a brand new alkaline battery starts at 1.65V o/c
and goes down from there.

Do you have reference you can cite for a well used one with a o/c
voltage of 1.8V?

no, haven't looked.
I have and 1.65 is the highest I saw for a new battery. An old battery
will typically be 1V.

these weren't new batteries

The only odd circumstance I can think of will be a duff meter.

I told you what the circumstances were. The meter's fine. But feel free to get stupid again.
Perhaps it was user error then, or not recognising a malfunctioning meter?

no

If you have any non "stupid" reason for the erroneous measurement,
please do let us know.

the measurement was not erroneous. Did I not already mention the cells had just been recharged? Short term overvoltage after charge is a routine phenomenon. Any EE knows this. 1.8v is unusually high but there ya go, consistency is not something that happens with post-charge voltage. Did we not cover this already?
Yes I did:
A well used one can go as high as 1.8v under odd circumstances. I had a couple do that earlier this year. They were well used then recharged, and gave a strangely high output. No idea why, none of the others did.


NT