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 don't recall the other ESR meter makers, or users of other brands
mentioning that the other products could be used for testing battery IR.

I've had Sencore Z-Meters for years, for testing capacitors and
inductors/coils. The ESR test will display values of low value resistors,
but there are some power resistors across the input connector initially to
discharge capacitors, so I don't think it will work for battery checking.

I just did some searching on eBay, and found a few China/Hong Kong
makers/sellers offering numerous small instruments specifically intended for
battery IR/ESR testing, from coin cells to car batteries.
There were also a couple of pulse load testers for common sizes of small
cells/batteries.

I noticed folks mentioning battery IR years ago, but they didn't ever
mention how they arrived at a reading. I didn't know if the IR was an
instrument reading or a calculation.
All I was able to find out then, was that the high-end equipment (Cadex) had
the capabilities of measuring cell IR.
Maybe some lab grade LCR instruments could measure IR, but I didn't find any
battery user comments that stated any of them did.
Those comments and the Flippers site comments got me started looking for
more info lately, regarding the significance of battery IR.

I was aware that IR and ESR could be determined by using generators and
scope, although there would probably be widely differing measurements. If
everyone is using different test equipment of various accuracies (and
different skill levels), there would not likely be any definitive IR numbers
to compare, from one specific brand of cell to a different brand, etc. (my
own WAG).

As cell IR is an indication of poor cell quality or degradation, it's also
an indication of the general condition of the cell.
Obviously, cell IR isn't a full evaluation of a cell, just as ESR isn't a
full evaluation of an electrolytic.

Since I'll be using about $300 worth of new cells to build some battery
packs, I'd like to have some idea of what's going into the packs.
So I'm interested in an *easy* test that would show me something I can't see
by looking at the cells (numbers would be good), although it definitely
doesn't need to be NIST traceable.

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


"John Robertson" wrote in message
news:__m4n.59846$Db2.10867@edtnps83...
Gerard Bok wrote:

Unless you are very sure that your milliohm meter is capable of
testing battery cells, I would strongly advice you not to try it.

General rule: don't apply anything 'active' to a device that is
supposed to measure resistance.


While that is true for older analog meter movements (always measure
resistance with system power off) modern meters such as the Bob Parker ESR
meter can read the resistance of a 'hot' circuit up to the breakdown
voltage of the input capacitor (roughly 50V). As such a meter like the Bob
Parker ESR kit (Blue ESR now produced by Anatek) can easily be used for
testing the internal resistance of batteries - the question is if that
produces useful information!

John :-#)#

--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."