9v Batteries

[Mike]

On 2/13/2019 9:01 PM, malua mada! wrote:

On Wednesday, February 13, 2019 at 12:48:23 PM UTC-8, Mike wrote:
You have the battery apart. What's the voltage on each individual cell?
If it's not the same, make it so.

3.823 3.826

That's gonna give you significantly reduced capacity.
If it were me, I'd set up the bench supply to 8.2V with a 50mA current
limit.
Hook that to the battery and again measure the cell voltages while charging.
That will give you an approximation to the internal resistance of the cells.

Increased resistance will cause the BMT chip to shut off charging
at a lower cell resting voltage.

Let it charge and see if it gets to 8.2V without shutting off.
They're rated at 8.4V, but I usually don't push 'em that hard.
It's difficult to know exactly what chemistry is used, but
lower voltage should improve cell life.

Another possibility is that the charger is crap. It has to do some
tests and make assumptions about which technology you're charging.
It may be getting it wrong.

 

[Martin Brown]

On 12/02/2019 17:34, OGEE wrote:
> Never had a serious problem with 9V batteries.

I have had the odd one go bad. Usually left in something for too long.

It is the AA and AAA DURACELL and KIRKLAND batteries that leak big time.

Still looking for reliable AA and AAA.

At least in the UK I have found that Kodak's cheapest nastiest batteries
survive in high current drain applications where Duracells have leaked
on me. EveryReady & Panasonic also seem to be OK at least in the UK.

Talking about 9V batteries is not helping !

I won't use Duracell any more. I can't tell if it is a problem with high
quality counterfeit or their actual genuine manufacture batteries. There
was a time in the past when they were the copper topped gold standard!

--
Regards,
Martin Brown

 

[Jeff Liebermann]

On Thu, 14 Feb 2019 11:16:24 +0000, Martin Brown
<'''newspam'''@nezumi.demon.co.uk> wrote:

I won't use Duracell any more. I can't tell if it is a problem with high
quality counterfeit or their actual genuine manufacture batteries. There
was a time in the past when they were the copper topped gold standard!

<http://www.learnbydestroying.com/jeffl/pics/Duracell/index.html>
Boom when shorted, probably because the gas vent plug was either
defective or missing. I didn't do the test or take the photos, so I
wasn't able to determine if they were real Duracell Procell or
counterfeit.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[pfjw@aol.com]

About the only sure method I have found to determine what is counterfeit and what is real, other than by very close examination of the 'fit and finish' is the weight.

Real batteries are typically significantly heavier than the fakes, even discernible between two AAA types. And if you have a 4, 6 or 10 pack to compare, it is even more obvious.

You would also find out when you send that damaged piece of equipment back to Duracell or Eveready and have them inform you whether the batteries are real or not.

Peter Wieck
Melrose Park, PA

 

[Jeff Liebermann]

On Thu, 14 Feb 2019 10:48:54 -0800 (PST), "pfjw@aol.com"
<peterwieck33@gmail.com> wrote:

About the only sure method I have found to determine what is counterfeit
and what is real, other than by very close examination of the 'fit and
finish' is the weight.

Real batteries are typically significantly heavier than the fakes, even
discernible between two AAA types. And if you have a 4, 6 or 10 pack
to compare, it is even more obvious.

Yeah, that worked for a while with LiIon 18650 cells.
<https://www.instructables.com/id/How-to-know-a-fake-18650-battery/>
Then, I started getting cells that all weighed about 65 grams, which
is rather high for an 18650. So, I cut one apart and found that it
was topped off with sand and some hot melt glue to hold the sand in
place. Foiled again.

You would also find out when you send that damaged piece of equipment
back to Duracell or Eveready and have them inform you whether the
batteries are real or not.

In this case, the friend that sent me the photos had already thrown
out the 9V battery. It didn't explode inside any equipment. I blew
up on his incredibly messy desk/workbench when the exposed terminals
were shorted by something conductive. If I had possession of the
remains, I would have doing my own autopsy on the battery, instead of
sending it to the manufacturer.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558