Milliohmmeter measures internal resistance of batteries, too

Check the condition of your car battery by measuring its internal resistance, without discharging it. Also track shorts and measure with high accuracy all kinds of low resistances: shunts, PCB tracks, contact resistances, relays, chokes and various windings, RTD sensors, etc.

This instrument is based on an AC low current very low frequency 4-wire resistance+ inductance measurement technique, which solves the issues of DC measurement errors. And it has the ability to measure the internal resistance (+ voltage) of DC current sources, with optional DC bias.
There are 4 measuring ranges from 1 up to 1000 ohms (best resolution of 10 microohms) with manual or automatic selection.
Powered by a standard 9V alcaline battery.
All details in the attachments.