ACM91 Digital Clamp Meter 1mA AC/DC Current True RMS Auto-Ranging 6000 Counts Meter Hz Temperature Capacitance Live Check V-Alert Low Impedance Voltage Tester

I originally bought this meter in July 2020. It worked fine until late October 2020, then just refused to come on. To their credit the manufacturer promptly sent me a replacement, even though this was beyond the normal return period. Needless to say, I was impressed. Unfortunately, the "new" meter does not read at all. As shown in the attached photo, a "cheapo" multimeter reads the battery voltage at 12 VDC while the ACM91 does not read at all. It did not read AC current, either. This cannot be ascribed to user error since I successfully used to first for three months. Too bad, because I really like this meter. Update: After reading my post, I heard from the manufacturer. They suggested re-inserting the probes because they were "not easy to insert." I followed their suggestion and inserted until I felt a firm "click." That solved the problem. I am glad about the meter but I am overwhelmed about the responsiveness of the seller. They were terrific.

This is a very decent clamp meter for the handyman and hobbyist. Its accuracy exceeds my expectations for such a low cost meter. This cheap meter doesn't replace a pro grade meter such as a Fluke, but for casual use around the home, does it really matter if a reading is 11.4 V vs. 11.3 V? What I like about this meter is its 1 mA resolution for DC amp readings using the clamp. For comparison, I also have an Extech 380942 clamp meter that I bought for $400 around 17 years ago. The Extech still retails for $400. The $400 Extech has higher accuracy specs than the $50 BSIDE ACM91, but the differences are slight. I spot checked several DC and AC current readings using the clamp at low currents (for example, around 25 mA DC, 130 mA DC, 330 mA DC, and 160 mA AC). The clamp-based readings between the Extech 380942 and the ACM91 essentially matched, differing by no more than 1 or 2 mA. The ACM91 was stable at low DC amp readings using the clamp and drifted a lot less than the Extech. Some caveman reviewers sounded like they never bothered to read the user manual and then blamed operator error on the meter. Some of them didn't plug in the test leads properly. One reviewer didn't understand that clamp readings only work with one phase (i.e. one wire) at a time. One operating detail that should be obvious is that the clamp only works when the test leads are removed. If the test leads are still plugged in, the clamp will give no reading. The most important thing about the DC clamp amp meters is they use a Hall effect sensor to detect DC currents. The manual specifically instructs the user to press and hold the zero button for 2 seconds to zero out the reading before taking a DC amp reading with the clamp. Some users didn't zero the meter and got wildly wrong DC amp readings and then blamed the wild readings on the meter. I'll add one further detail not mentioned in the manual to help give better DC amp accuracy when using the clamp. Once you've zeroed out the DC meter, hold the meter in the same orientation when taking readings. Don't tilt it, twist it, or rotate it. Otherwise, changing the orientation of the meter can give false readings due to different magnetic flux through the clamp from the earth's magnetic field when the meter is oriented differently after it's been zeroed. A main drawback is the meter screen is very hard to read. It has a curved protective lens and it's almost impossible to avert reflected light due to the curvature of the lens. A flat surface would have worked much better to minimize reflections.

I was hoping to use this meter to measure parasitic draw on car batteries, using just the clamp. Prior reviews implied that it could resolve a few mA but that's nonsense. The specifications for this mode (contactless dc current measurement) are +/-3% +5 counts. Since the minimum range is 6 amps, that means the accuracy is +/- 180. milliamps, +5 counts. That's not nearly good enough to see the parasitic current draw a car battery (and let's not get into issues of frequency response and intermittent current drain). To be fair, measuring small dc currents by the magnetic field they generate (which is how contactless/clamp measurements work) is hard to do. Stray magnetic fields will overwhelm the tiny signal from the hall sensor. Just moving the meter a few feet will change the background. But if you want to measure a few to tens of amps, this meter is very conveinent. That said, the dc voltage measurement closely tracked my expense Fluke DVM over a 0- 30 volt range which is impressive for an inexpensive meter. I did not test the dc uA range (which is done using the probes, not the clamp), nor any of the other modes.

Perfect for diagnosing battery drain. I read one review that said this was not accurate but I found it more than accurate to diagnose a draw. Just make sure you orient the meter and zero it before connecting the the negative cable. I have a known led light that draws 98mv and this meter sees it correctly. Plus it is great for around the house with its ability to identify a hot circuit and tell you which wire is hot and which is neutral. Love the small size, it is easy to travel with. Overall very satisfied.

We use this inductive ammeter routinely in the auto shop to check for parasitic drain. It can read low current and allows us to check for excessive draw without disconnecting the battery to insert a multimeter in series. It is considered an acceptable method, works well for us, and saves time.

Heard this one had good DC read in smaller scale, but it's +/- 75% around 100-200mAmp clamp draw - will basically tell if you something is drawing a current or not....or it appearance....Voltage measure. But, since the clamp is inaccurate why get another voltage meter is the question? Not sure if it's too sensitive or not just doesn't work ???? Who knows!!!

I needed a inductive DC ammeter for a project and decided to give the BSIDE ACM91 a shot. I'm glad I did because it works very well and is accurate as far as I can tell. I only used it for DC amperage and some DC voltage measurements so my testing is limited. For the price I can't see it getting any better than this.

The only thing this meter is good for is measuring DC amps! Didn’t try temperature or voltage readings because I have enough meters to do that! So I will have device for quick check weather alternator works - that’s about it The one that I got does not measure AC - readings jumps all over the place!