Hi Justin:

The equivalent circuit of a battery is complex and contains a number of tim=
e constants so the impedance of a battery=20
depends on the test frequency.

Here are four instruments that can be used to measure the internal resistan=
ce of a battery:
http://www.prc68.com/I/BatTst.shtml#IR

I found when doing pulsed discharge of batteries to measure their operating=
 time when used with a radio where you only=20
transmit one minute out of 10 minutes the size of the steps (related to int=
ernal resistance) varies and I expect a=20
similar effect when pulse charging.

It's interesting that in the days when the No. 6 dry cell was used for tele=
phones and car ignition systems they tested=20
them by applying a short and measuring the current (Flash Amps).
http://www.prc68.com/I/No6.shtml#FA
PS Don't try this with a modern DMM because it will blow the expensive fuse=
 that's inside (guess how I know that).

Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html



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