Hi alan:

A long time ago batteries were tested using an ammeter (not voltmeter) that was 
in a pocket watch case.   http://www.prc68.com/I/No6.shtml#ERPAM

Later the test was codified as the "Flash Amps" test and consisted of applying 
a 0.01 Ohm load to the battery for 200 ms.  This comes close to what was 
happening with the manual ammeter.
http://www.prc68.com/I/No6.shtml#FA

I've measured a number of modern batteries using the old pocket ammeter and 
have the data at:
http://www.prc68.com/I/No6.shtml#MFA

I think any battery will work if you make all the connections low resistance.

The problem with using a capacitor is that they have leakage current that's 
proportional to the capacitance and will drain the battery sooner than what 
would happen otherwise.

When looking into making a Flash Amp tester I found you can not get any solid 
state device with an on resistance low enough, hence the choice of automotive 
12 V Bosch type relays.

Have Fun,

Brooke Clarke
http://www.prc68.com



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