Internal resistance of the battery, practical verification of tester readings.
We're reviewing two 12-volt batteries: a Ventura 100Ah (old and worn) and a relatively new Delta 9Ah. The lower the internal resistance, the better the battery. The tester measures internal resistance under a load of approximately 1 amp of alternating current at 1000 Hz. Resistance is measured in milliohms (mΩ). Should we trust its readings? We're testing with a real load of stabilized direct current of 6.5 amps.
https://alii.pub/724xrq?erid=2SDnjcF7qoh - Ancel BST100 tester