The biggest issue with these 4-wire-meters is that they do not do a plausibility check of the 4W-connection.
Immediately noticed that, at least it's common among this family of devices.
Due to the same reason I build some pseudo-4W-test-leads where the L- and U-lines are both soldered to a short and sharp test needle. That way the contact resistance is of course not compensated, but for quick comparison of many parts it´s more reliable - and you can always fall back to the true 4W-leads if doubts arise.
I thought about that as well, still have some DIY DMM probes lying around I could use for that. But wouldn't that effectively only eliminate the resistance of the leads from the equation? I'd assume contact resistance is the far bigger issue. When trying to use this meter in-circuit I noticed the dual tipped probes are too far apart to ever make contact with SMD parts. Maybe I should try ordering a clamp lead for it?
Beside that it´s a really versatile tool. Not only for batteries but e.g. also for in-circuit test of capacitors or as a milliohm-meter for plugs or switches.
Ahh, yes, it used AC for resistance measurements, right? I already have an in-circuit ESR meter, was more thinking about using it for short finding. In a quick test I setup it was perfectly able to indentify which of the several resistors was the 0-Ohm one, so it should work.
I'll have to measure the current flow with my clamp meter but the open line voltage was already quite high. I'd be a bit afraid I'd fry something when doing measurements.