Could some electronics guru please shed some light
on this ? What is an approximate impedance value
for a flooded lead acid cell battery, e;g., a 12V
32 AN cell. I have gone through a number of online
sites and material, e.g., 'Battery Univerdity but
that has not been of much help. Thanks in advance,
That's a very vague question. What are you trying to
accomplish?
Do you really care about the impedance? Over what
frequency range, state of charge, temperature, age???
Maybe you're interested in the equivalent series resistance?
But what is that really?
Maybe you want to know how much the voltage will droop
when you load it?
That's easy...well...no it isn't.
A battery that's been sitting will have some relatively
high voltage. That voltage will drop rapidly at first,
then settle down to some lower rate.
The only way I've found to reliably gauge actual battery
performance in an application is to emulate the application.
Typically, I start with a fully charged battery.
Let it sit for a while.
Add the anticipated load and sit for a while.
Add or subtract come current and measure the change in
voltage. Use deltaV/deltaR as the dynamic resistance.
The definition of "while" in each case depends...
Graph the data and pick a time that works to get you
the info you need.
Realize that sulfation will dramatically increase the
dynamic resistance as the battery ages.
Another interesting experiment is to use a pulse load.
There'll be an initial step in voltage that's sorta
related to resistance and a more gentle slope that's
sorta related to chemical reactions.
When people ask that sort of question, they're often
contemplating HIGH charge/discharge currents. That's
a different bucket of worms.