***They actually work!
I have one of these and I can attest that they are infact decent.
At one point, we lopped the leads off one like these and put on an Anderson connector. I’m not saying it’s remotely adequate when held up to a CBA or Battery Beak, but it’s better than nothing.
Hey, pick up an old sealed-beam incandescent headlight at an auto junkyard and you got yourself a reasonable battery tester.
Hook the headlight (30 to 36 watts) up to a freshly-charged battery and leave it on for 2 hours. If the voltage across the battery after 2 hours (with the headlight still on) is less than 12 volts, you’ve got a weak battery.
They get the job done. There are often coupons for these DVMs where they are free with a purchase at Harbor Freight.
They do work just fine for the most part. I have several, however, I have found them woefully inaccurate when attempting to measure resistance to any degree of precision. Part of the problem is the probes oxidize over time, and the leads do not plug into the meter terribly well. For $4 (I actually got a few free), I can’t complain though. They’re good for class projects and to throw in a travel box or bag. But, I still keep a quality meter around when needing to measure resistance.
Does HF sponsor any FRC team(s)? Every time I think one dozen 1/8" drill bits will be enough for my power-mad riveters, I really should reconsider and save myself a trip back there. (for instance)