Testing Nicad/nicd or NiMH cell ESR or SLA Gel Cell Battery

[Jeff Liebermann]

On Fri, 15 Jan 2010 18:48:02 -0500, "Wild_Bill"
<wb_wildbill@XSPAMyahoo.com> wrote:

One source that appears to be reliable is
http://www.buchmann.ca/default.asp

That's Isidor Buchmann's (Cadex) site and runs kinda slow. The public
info is at:
<http://www.batteryuniversity.com>
I agree. It's the best battery reference I can find.

--
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

 

[Wild_Bill]

Yep, Phil, your conclusions as to the points I'd been referring to are
correct.

In particular, I meant to mention the comparitive testing issue, but forgot.

Much of my workbench testing is comparative anyway, and it's not as though
rechargeable cells are marked with their IR specification.

I decided to try a cheap cell/battery IR tester and may expand to some sort
of controlled discharge-type analyzer later.
http://cgi.ebay.com/New-Internal-Battery-Resistance-Voltmeter-SM8124-0-200V_W0QQitemZ290345697222

Or, item 290345697222

--
Cheers,
WB
..............


"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:7rff9rFobhU1@mid.individual.net...

"who where"
"Wild_Bill"


I don't presume to know.. internal resistance is a factor, maybe not the
most critical, but a parameter that could be useful. As I've said, I
believe
ESR/IR is more useful than a simple battery test meter.
As the cell's IR increases, it's capacity drops, from what I've read.

No. Note TWO relationships: (1) Internal resistance will have an
effect on the usable capacity, in that it will result in earlier
discharge termination at the terminal voltage will droop more under
load. (2) As the cell's usable capacity reduces due to "wear and
tear", the internal resistance will usually rise for similar reasons.
But IR is NOT the cause of reduced capacity.

** Bill's post does not say it was - only that there is a correlation.

There is a strong correlation between measured ESR and state of charge for
non-rechargeable cells - but it is only when a NiCd or NiMH cell is
almost completely discharged that the ESR rises.

The whole idea is that ESR testing is a COMPARATIVE measurement applied
to a *number of cells* that are of the same type and with a similar
history to see if any show higher readings than the others.

It is also useful to apply ESR testing to a pack of cells and see if the
total ESR is any more than slightly over the typical ESR of each cell
multiplied by the number of cells. A higher than expected reading
indicates one or more bad cells or possibly high resistance spot welds
inside the pack.

It can take hours to do a charge and discharge tests on a packs of
ells - but only SECONDS to do an ESR test on a pack and find immediately
that no further testing is warranted.



.... Phil

 

[Wild_Bill]

Thanks for posting your experience with the Blue ESR Meter, Fred.

Keeping notes on various measurements has been a regular habit of mine
almost any time I'm testing or evaluating.

I think I know whatcha mean Fred, about not being sure exactly what the
readings indicate.
There sure won't be any numbers on a new battery regarding what the internal
resistance should be.

For decades, all I ever heard about any lead/acid battery's state-of-charge,
was specific gravity readings from a hygrometer.

Then a few years ago, I noticed an off-grid guy talking about the internal
resistance of LA batteries being a significant indication of the general
condition, or the amount of useable capacity remaining in used batteries he
was scrounging.
His remarks and others who also depend upon battery power because they're
off-grid, gave me the impression that they were seriously interested in
being able to gage and monitor their batteries.

The other point of his website was concerned with desulphator circuits he
had built to recover servicable life from used heavy duty commercial
batteries he could get for free.

So, as I did more looking for info regarding battery internal resistance, I
discovered that many others were interested in the IR of all types of
batteries.
Lots of reading, but no explanations that I could find, of how those folks
were determining the IR.

--
Cheers,
WB
..............


"Fred McKenzie" <fmmck@aol.com> wrote in message
news:fmmck-EBCF5B.21204916012010@5ad64b5e.bb.sky.com...

In article <N8q4n.102263$N07.18146@en-nntp-05.dc1.easynews.com>,
"Wild_Bill" <wb_wildbill@XSPAMyahoo.com> wrote:

I remember reading the comments regarding the use of the Bob Parker ESR
meter for checking battery IR/ESR quite some time ago, John, and also
Bob's
own descriptions of his circuit.

I have used the Anatek Blue ESR Meter with various cells and batteries,
including the 12 volt lead-acid battery in my car. The problem is that
I don't know how to evaluate the readings.

If you are going to use that technique for battery measurements, I'd
suggest building a library of measurements of cells in various states of
charge. It would probably work for both NiCd and NiMH cells, unless one
of them happens to have a resistance below the meter's limit. In my
limited experience, the cells were all within the meter's range.

Fred

 

[Phil Allison]

"Wild_Bill"

I decided to try a cheap cell/battery IR tester and may expand to some
sort of controlled discharge-type analyzer later.
http://cgi.ebay.com/New-Internal-Battery-Resistance-Voltmeter-SM8124-0-200V_W0QQitemZ290345697222

** Wow - 0.1mohm resolution.

Those test probes will sure have to make GOOD contact with the cells.



.... Phil

 

[mike]

Phil Allison wrote:

"Wild_Bill"

I decided to try a cheap cell/battery IR tester and may expand to some
sort of controlled discharge-type analyzer later.
http://cgi.ebay.com/New-Internal-Battery-Resistance-Voltmeter-SM8124-0-200V_W0QQitemZ290345697222


** Wow - 0.1mohm resolution.

Those test probes will sure have to make GOOD contact with the cells.



... Phil


Why?

 

[Phil Allison]

"mike"

Phil Allison wrote:
"Wild_Bill"

I decided to try a cheap cell/battery IR tester and may expand to some
sort of controlled discharge-type analyzer later.
http://cgi.ebay.com/New-Internal-Battery-Resistance-Voltmeter-SM8124-0-200V_W0QQitemZ290345697222


** Wow - 0.1mohm resolution.

Those test probes will sure have to make GOOD contact with the cells.


Why?

** Huh ?

The comment EXPLAINS itself.


..... Phil

 

[mike]

Phil Allison wrote:

"mike"
Phil Allison wrote:
"Wild_Bill"

I decided to try a cheap cell/battery IR tester and may expand to some
sort of controlled discharge-type analyzer later.
http://cgi.ebay.com/New-Internal-Battery-Resistance-Voltmeter-SM8124-0-200V_W0QQitemZ290345697222

** Wow - 0.1mohm resolution.

Those test probes will sure have to make GOOD contact with the cells.


Why?


** Huh ?

The comment EXPLAINS itself.


.... Phil


Assuming I RTFM'd the right manual, it's a Kelvin probe.

 

[Phil Allison]

"mike"

** Wow - 0.1mohm resolution.

Those test probes will sure have to make GOOD contact with the cells.


Why?


** Huh ?

The comment EXPLAINS itself.


Assuming I RTFM'd the right manual, it's a Kelvin probe.

** What planet are you on ??




..... Phil

 

[mike]

Phil Allison wrote:

"mike"

** Wow - 0.1mohm resolution.

Those test probes will sure have to make GOOD contact with the cells.


Why?

** Huh ?

The comment EXPLAINS itself.

Assuming I RTFM'd the right manual, it's a Kelvin probe.


** What planet are you on ??

Obviously, not the one you're on.

.... Phil

 

[Phil Allison]

"mike"

Phil Allison wrote:
"mike"

** Wow - 0.1mohm resolution.

Those test probes will sure have to make GOOD contact with the cells.


Why?

** Huh ?

The comment EXPLAINS itself.

Assuming I RTFM'd the right manual, it's a Kelvin probe.


** What planet are you on ??

Obviously, not the one you're on.

** For sure - cos you are living on planet Fuckwit.

A tiny, very cold and dark place full of dribbling morons only in contact
with Earth by usenet.




..... Phil