So, are those freebie HF multimeters any good?

[e9999]

If you're like me, you probably have had several, maybe have several at a given time (it's one of the better freebies they have I think). I use them primarily for rough measurements of voltage on the truck and 120V outlets at home. Some uses for which you may not want to use or buy (or risk) a good one.

I do remember once being annoyed with a perceived large error I got with a HF one when comparing to my Fluke. May even have mentioned it here. I don't remember the details but that made me a bit leery.

Anyway, I was playing with some batteries and I had some toys out so I figured I would check to see how good my latest HF freebie multimeter is for the typical truck battery measurement. Unfortunately, I only have one left as I routinely give them away to friends when they need one, so I could not do a comparison with 2 units (which may be of interest given the likely inconsistent QC for these units.)

So I took a good power source and a bench voltmeter and compared the measurements for that voltmeter (5 1/2 digits, accuracy is 0.004% of reading plus 2 counts in that range; a few $K originally but older), a Fluke 179 (a good True RMS handheld unit for semi-serious work, about $150) and a CenTech 92020 (the HF freebie, it's the one with the Backlight). The power source is stable to 100 microV and the bench voltmeter had a resolution of 100 microV as well. Note the measurements were all stable and showed a fixed number on the display, meaning no fluctuation and no averaging here, except when I list a "5" at the end for the handhelds which was when the last digit was oscillating regularly between 2 consecutive digits. Here is what I got for the voltage range of interest for the truck. Note: you really want to be in the lowest range possible on the HF or the errors will be significantly larger.

SourceV Fluke179 HF

11.0046V 11.00V 11.00V
12.4290V 12.425V 12.425V
12.6008V 12.60V 12.60V
14.4256V 14.42V 14.42V

OK, pretty rough and quick test of course, but enough to give me an idea of how reasonable the (this?) HF is. I was thinking it'd be good within 0.1V which is not enough to get a good idea of how well charged your battery is. But in reality, with this particular unit at least, it seems to be good within 0.01V. Not too bad for a freebie and as good as the Fluke for this (DC) measurement. And gives me another incentive to use this one when there is a chance I'll fry -yet again- the fuse on my better meters. Is this one particularly good or are they all like that? Don't know (yet). YMMV and you draw your own conclusions of course. But I'm feeling a little better about using that HF freebie.

 

[Cruiserdrew]

I think they are pretty darn good for what you get. I've had several over the years and for measuring continuity and checking voltage they are fine. I recently got a better meter, but I am considering stashing one of these in each truck. Even if you buy one, it's like $2.99. The one thing these lack that is seriously nice to have is a continuity beep.

For better reliability, immediately ditch the 9V it comes with and replace with a better 9v battery.

Fluke meters are by far the best. But they are pricey!

 

[e9999]

absolutely worth keeping in the truck. Very useful to have one around to check connections, fuses etc. I normally have one in my take-along tool kit.

 

[george_tlc]

Yeah, they're ok as disposable meters. Fine for leaving in the truck (as above, put a decent alkaline 9V in there). I've got one in each of our vehicles.

The real test would be to warm (to say 50C) and cool (to say 0C) and compare with a room temperature fluke so at least you also know if the voltage reading is reasonably accurate for outdoor/vehicle use.

Certainly plenty good enough for debugging go/no-go issues when out camping etc. Keep a decent meter at home for accurate measurements.

THOUGH - while open, check the soldering. Here's a HF meter that I had spare - just checked it and it was rattling inside... Opened it up and the +ve 'socket' had fallen out due to piss poor soldering - see picture below. I've soldered it up decently now.

EDIT: I would **NOT** trust them to measure 110VAC, regardless of the B/S Cat rating they claim... 12/24V DC stuff is all I'd recommend...

EDIT: Remove the board for soldering so you don't 'melt' the plastic 'guide' for the 'socket'.

cheers,
george.

 

[e9999]

It's amazing how little there is in there considering how much the thing does. That's Electronics for you. How things have changed! You should see the size of some of my old power supplies... Not to mention the nominal cost of the thing when you think it took a 10000 miles trip to get here probably.

Good point about the 120V. That is an issue. Not too worried about it actually but never know. It does say Cat II on mine I think, which should be OK, but -indeed- who knows how they came up with that.
I just looked up the ratings on my Fluke 179. They say CAT IV 600 V/CAT III 1000 V. That is better.

 

[e9999]

well, talk about ironic...
Today, I was doing some more creative charging of NiCads and was using several multimeters. I was using charging currents below 200mA most of the time. The HF was doing pretty well, actually, compared to better meters, current readings were very close. But at some point, it stopped registering current readings. So I figured that I must have blown the fuse by going over 200mA at some point (the stated limit). So I opened it up, took the fuse out and checked it. It was fine (and 500mA actually). But interestingly given George's post above, I saw that either originally, or due to pulling the fuse out, the fuse holders were loose to the extent that they were wobbling in their solder bond on the board. So had to resolder those. Now, they are secure. Watch out when pulling those fuses out, be gentle. Maybe you want to hold the support down while pulling the fuse up. (Also, interestingly, I didn't see a 10A fuse, so that circuit is likely fused by the meter itself. If you see it smoking and melting in your hands, the current is too high..!)

The mA measurements still not working though. (Although the 10A bit works.) And I can see a significant drop in current when I go through that circuit. Something not right. But eh, still damn good considering the $0 price! May need to get myself a new one... or 3...

 

[TXLX100]

I have a couple, one for each vehicle. They work fine, I only check voltage in 12 and 110 with it. . I actually use those because I blew the fuse in my good one and never replaced it. I had one HF unit break at the wire connection on the unit and HF replaced it. For $0-$5, it's a bargain.

 

[LandCruiserPhil]

I have several HF meters along with a few Flukes and use them all for DC and AC but for anything else I use the a Fluke. I would use a HF meter for AZ 110V before I would use a beeper or a test light.

 

[e9999]

I have to come up with a good routine that will prevent me from zapping my meters just about each time after measuring currents... Dammit! Getting old! Anything fool(!)proof out there...?

 

[rusty_tlc]

The cool thing is the A to D converter in the HF meter uses an internal reference so they are actually pretty darned accurate, even over temp. It's the rest of the meter that is junk, cold solder joints, a crappy switch contact, and really cheap sockets for the test leads.

Now the kicker, I had a Fluke at work that was acting flakey, intermittent readings random blanking of the display etc. replaced the battery, no joy. I popped the case and found the same POS lead sockets, one of which had a cold solder joint that had fractured to the point the lead connection was intermittent.

I was very sad.

I'm hanging on to my old Fluke meters.

If you want a slight upgrade from HF check out Vellman meters, they are a cut below Fluke but better than HF. Not sure about now but they use to come with a NIST traceable calibration cert. Funny thing is it was cheaper to replace them than calibrate them so the cert was worth more than the meter.

For basic automotive/household trouble shooting almost any meter will do the job IMHO.

If your experimenting with electronics it's probably worth the extra money to get a decent bench top DVOM, I like Keithly for that.

 

[TXLX100]

I have to come up with a good routine that will prevent me from zapping my meters just about each time after measuring currents... Dammit! Getting old! Anything fool(!)proof out there...?

Put a bright yellow dot on the dial so you remember to set what you are testing. I've blown up a couple in my day.

 

[skidplate]

I have one in each car and a few, unopened in my work bench. They've done everything I asked it to do. I do have a Fluke in my electrical box but the HF is usually closer at hand.