Part 2 of Testing the Kaiweets HT208D Current Clamp Meter

[@jaymclemore9497]

I’m a little surprised at the inaccuracies of this meter. I have always thought of Kaiweets being reasonably accurate for it’s price point. Very good test review. Thanks!

[@three-phase562]

Glad you liked the review. The clamp is still reasonably accurate in comparison to some clamps, its just that I could not get it to meet the manufacturer's specification. It was an Amazon purchase, so I may have been unlucky, don't know anyone else who has one though to run another set of tests on.

[@JAKOB1977]

Very impressive testing approach. and no hidden agendas and trying to sell it, just let reality stand on its own two feet and exactly how it should be.. also got a variant of this clamp meter, though its the Habotest version HT208D. its somewhat cheaper and the only difference I can tell is the probes, that is some tacy cheap ones and not the silicone'ish variant from the Kaiweets.. Its pretty new just arrived, but will try to test it out to see if I get the same variables., or at least as good as my noob'ish knowledge & tools can manage. thx for one thorough testing.. subscribed as I like the honest approach that takes center, at least in the video above i just saw.

[@three-phase562]

Thanks for subscribing. A number of Habotest instruments do seem to be the same as Kaiweets, I have only purchased the Kaiweets ones though. Hope you get on with your meter well.

[@sadfur8728]

4:46 have you compared measurements with the 50 turn coil using another clamp meter to see if the flux stimulating an actual high current is accurate? I wonder if the high number of turns will match the theory or if they affect the readings.

[@three-phase562]

Yes the coil has been tested against numerous other clamps without any problem. This particular coil is a professional unit from Transmille and is UKAS calibrated.

[@SiteReader]

After the dialog here, I complained to Kaiweets customer service about the poor performance of my HT206D and they sent me a free replacement! That's something in their favor. I think the basic problem is that this meter does not measure down to milliamps which is what you need to detect many automotive parasitic drain situations. I looked at the UniT with a 2A scale that you mentioned, and then found a Mestek unit with 2, 20, and 100A scales, and a millivolt accuracy on the 2A scale, for a little cheaper. It arrived a few days ago. It's detecting a very small parasitic drain, but varying from 1 to 20 mA over a 5 to 10 minute period. That seems odd, but may be a built-in feature of the car's electronics. That is an acceptable amount that should not drain the battery for months. So now I need to figure out why my nearly new battery drained last time after sitting for 2 weeks. I use this car infrequently for certain purposes. Perhaps I am not driving enough to recharge it sufficiently, or there is a fault in the charging circuit. I'll use the new current clamp to check alternator output next.

[@three-phase562]

Glad you got some response from Kaiweets. 20mA doesn't seem too much of a drain. I think my car takes around 4 weeks to drain its battery to the extent that it won't start. Worth checking the charging circuit. If you only use the car for short trips, then that will also reduce the charge going in. I know you said the battery is nearly new, but sometimes you do get a faulty on from new with a reduced performance.

[@jimsjacob]

Most unfortunate…. I bought this meter to verify peak amp draw on startup for my HVAC unit. I’ve purchased a soft start unit and had hoped to capture the before and after. I guess I’ll get a “value”, but it won’t be accurate. I’m wondering if you just got a faulty unit? Thank you for the very thorough testing on both Video #1 and #2. Best I’ve seen so far. Well done!

[@three-phase562]

Thanks for your kind words. I am not sure if the unit is faulty or just badly calibrated. I did ask Kaiweets for a calibration procedure, but they weren't forthcoming, despite swapping numerous emails about the issues. One of these days I will sit down and see if I can adjust it to give a better performance. Whilst the absolute value may be out on your unit the percentage improvement would likely give you a more accurate assessment of the difference in the startup current. i.e. both before and after values measured should be out by a similar factor, so the calculated percentage difference will be less effected. Your other way to measure the difference would be with a scope and clamp adapter if you have one.

[@jimsjacob]

@@three-phase562 Spot on. I came to the same conclusion. While the values might not be accurate, the difference in pre and post amounts should be.... Kind regards

[@three-phase562]

@@jimsjacob 👍👍

[@TheUltimateDIY]

the ht208 clamp can be calibrated with calibration potentiometers, inside, there are 2, have you tried to calibrate manually? that would have been interesting to see.

[@three-phase562]

I haven't tried any adjustments, I did ask Kaiweets for a calibration procedure, but they never sent one through. It is something I may try to do in the future if I get time and the test set is set up.

[@TheUltimateDIY]

@@three-phase562 the youtuber: "Viorel Caia" made a video on it the name of his video is: Kaiweets 208D clamp meter calibration. curious to see your video too.

[@three-phase562]

@@TheUltimateDIY Thanks, I will take a look at the video.

[@AdamMaszynotwor]

thanks :)

[@three-phase562]

Appreciate you watching and commenting. 👍

[@Hartech100]

Why did you not Zero the Kaiweets before current measurement? I am sure the accuracy will then improve. Manual specifies Zeroing. Read the section on zero button and current measurement.

[@three-phase562]

The meter was zeroed at 2.44 in the video, thanks for watching part of the video and commenting.

[@three-phase562]

The meter was zeroed whilst around the test coil as there was no current flowing though it. All zeroing of a DC clamp does is remove the offset caused by residual magnetism around it. Therefore the most accurate way to zero it under this scenario is with it clamped around the coil and in the position it is being tested in. Under normal work conditions measuring on a live circuit, it is unlikely you can do that, so in that scenario, you would zero the meter prior to clamping the wire.

[@SiteReader]

Thanks for the video. Can you clarify something for me? What is the correct position of the clamp on the wire for DC current testing? You seem to have the wire running parallel to the plane of the meter in your test rig. Is it all right to have the wire running perpendicular to the plane of the meter? I get a reading this way, and it is more convenient in my arrangement where I am trying to measure parasitic drain on a car battery. An added confusion for me is that I watched an instructional video from Fluke where they show the clamps not even closed on the wire; rather the wire fits loosely within the open space enclosed by the clamp. (Perhaps this works for AC?) Please clarify.

[@SiteReader]

I should add that my Kaiweets instructions only say "make sure the wire is centered in the clamp," which leaves it ambiguous whether that means touching the clamp or within the open space enclosed by the clamp. There is no diagram.

[@three-phase562]

@@SiteReader The wire needs to run through the hole in the clamp meter tongues. In an ideal world, it should be in the middle of the hole and should be kept away from the meter. This is when it will be at its most accurate. However, that is not always possible when making readings in the real world. When not centraised, you may lose a bit of accuracy, but clamp meters generally have a relatively high tolerance anyway. For AC current you are utilising the magnetic circuit made by the clamp tongues so they must be closed otherwise accuracy is seriously affected. For DC current, the clamp tongues are not used, and it is actually a small hall effect sensor embedded inside the instrument that is detecting the current, therefore the clamp does not have to be closed for DC. You just have to do the best you can when measuring, try moving the wire around inside the clamp to see how the reading is affected. It will depend on what value current you are looking at as well. Less than a couple of amps and this meter is not all that accurate anyway.

[@sadfur8728]

​@@three-phase562 the clamp should be closed for current measurement regardless of AC or DC, did you find that the measurement of DC current is unaffected by the clamp being open?

[@three-phase562]

@@sadfur8728 Yes, ideally the tongues should be closed for DC measurement to get the best accuracy. It will depend how the hall effect sensor is physically mounted into the meter as to the effect. On the Kaiweets, I got about 1A differential between an open and closed clamp, but i did not test across the whole range of the instrument.

[@2cents177]

like to know VFD frequency reading

[@three-phase562]

Thanks for watching, I haven't tried the Kaiweets on a VFD yet.

[@SiteReader]

Just got back from my garage with a much reduced opinion of this clamp meter. I've had it over a year and never felt I could rely on it for much, but my recent test just proved just how absurdly inaccurate it is. As I explained in previous post, I am trying to track down a parasitic drain in my 2001 Ford Taurus. The clamp meter was showing a 0.48A drain on the lead from the disconnected negative terminal, and a 0.23A drain on the positive terminal with the engine shut down and all systems off. Something was peculiar about this because it did not change over time, whereas there should have been an increase when the electronic control system "woke up" and a decrease when the control system "went to sleep." To see if the problem was with the clamp meter, I disconnected the lead to the positive terminal of the car's battery. The clamp meter still read 0.48A. and stayed at that value after multiple on/off cycles of the meter, disconnecting and replacing it on the wire, and zeroing out of the DC amp function. Then I disconnected both negative and positive terminal from the battery, and still found a 0.48A reading with the clamp on the disconnected negative lead and 0.23A when clamped to the disconnected positive battery lead!! What is this meter responding to--the thickness of the wire? I tried it on a random 6-inch length of wire that was connected to nothing, and got a reading somewhere around 0.28A. Laughing to myself, I next put the amp clamp around the shank of a flat head screw driver. It read 3.63A and flashed orange! Perhaps there is some residual magnetism in the shank which confuses the meter. But what about the disconnected copper wires? Judge for yourself if you want to trust this piece of junk for anything other than entertaining an infant with flashing lights. As far as my real problem, there is indeed some sort of drain through the negative battery lead, because when I connected my trustworthy Simpson meter between the disconnected negative terminal and ground, the built-in circuit breaker repeatedly though intermittently tripped. I believe I have a faulty controller unit, known in Ford lingo as a GEM (generic electronic module). I decided to order a used replacement on eBay and see if it fixes my ongoing problem of a new battery dying after a week or so of not driving the car. . . . Thanks again for your video.

[@three-phase562]

I have just tested my Kaiweets against a magnet and also the Flir CM46 and UNi-T UT216C. I can zero each of them and they all stay on zero, but all of them will respond to the magnet 8.13A for Kaiweets, 8.25A for Flir and 7.64A for the Uni-T. This was with the clamp closed and the magnet placed at the joint between the tongues. So they all seem to suffer from that issue. My Kaiweets did not flash orange though. If you cannot zero the reading on your Kaiweets, then there could be something wrong with it. I do not know if it is possible to magnetise the iron core in the tongues, if it has been subjected to a strong magnetic field. I know there are a few people who have purchased a Uni-T UT210 for work on motor vehicles as it has a 2A DC range. It is relatively cheap and seems to have predominantly good reviews on eevblog. It may be worth a look if you can't get any joy from the Kaiweets.

[@SiteReader]

@@three-phase562 Thanks. I suppose there is a small permanent magnet inside the Hall effect probe. Perhaps this can get disturbed by high currents? I just noticed you have a video on the teardown of the Kaiweets 208D. I'll have to look at that. Believe it or not, I have read Edwin Hall's original paper on the effect he discovered, but am far less familiar with the circuity in a modern Hall Effect sensor. I'd like to understand it better, as it could possibly explain what I might have done to my device. (Or maybe it was defective from the beginning?) I'll also look at the Uni-T UT210. Thanks again.

[@three-phase562]

@@SiteReader If you have never been able to zero the DC current, then that to me is wrong and the meter is likely defective from the beginning. If you used to be able to zero it but can't now, then something has failed either through use or a longer-term defective material. I only took the back cover off the meter, as I am more interested in the CAT protection offered by the meter.