recommended multimeter?

System
System Posts: 2,511 admin
in Advanced Solar Electric Technical Forum #1
I need a decent one but hopefully not too pricey, mostly for low-voltage DC stuff.

The last 2 $10 units I bought failed after a short while. In reading some product reviews at radioshack.com, I see that this is a very common occurrence even with more expensive ones.

I do have a cheapo from 1984 that still works, but reads way too low on voltage. Plus I accidentally blew out the amp meter part of it.

It doesn't have to be fancy, but I'm willing to pay extra for reliability, accuracy, and (I'm not sure this exists) a warranty.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #2
    Re: recommended multimeter?

    Loohan,

    1. The defective current range is almost always a blown fuse inside the case. Usually 0.315 Amp or perhaps 0.250 Amps. These small glass fuses are often avail @ RasioShack. The fuse is usually blown when trying to read Volts while the meter switch set to Amps.

    2. Cheapo meters often work surprisimgly well. The first thing to go is either the fuse, or perhaps the cheap leads/probes fail. Next might the drops onto hard floors cause failure.

    If the wallet permits, perhaps a Fluke or some such known brand name. Perhaps one which is ruggedized with impact absorbing case. True RMS funciton is a nice plus and so on. Have numerous DMMs here so have not bought one for a long time, have no specific model in mind.


    Perhaps one good one and a cheapo or two for more general use, and mabe save the good one for critical measurements and as a standard to compare the cheapo ones against. Use the cheapo one to bang around, when a measurement seems questionable, compare against the best one ... kinna what I do, altho "you don't know what you don't know" !

    The Experts will have better advice. Some of the cheap meters lack important ranges, like lower values of AC and some Ohms ranges, but it amazes me that one can retail a DMM for $3.00, with battery -- such as the Harbor Freight ones. Good luck Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • System2
    System2 Posts: 6,290 admin
    #3
    Re: recommended multimeter?

    Well, I checked the fuses, batteries, battery connections at the time. The Velleman digital does get some dots and stuff on the screen, but won't read.

    The other is a G-B analog, and I have misplaced it somewhere, but seem to recall it just doesn't respond to anything anymore.

    Another thing is (I think this was only with the Velleman) that the jacks and wire plugs didn't connect well. When it was working somewhat, I would have to fiddle around and twist where the wires plug in while trying to do everything else.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #4
    Re: recommended multimeter?

    Loohan,

    OK, sounds like the Vellman is dead. Most of the GB units I've seen are very modest meters, sold at home improvement stores etc.

    You DO deserve a good meter. Perhaps you can find a Fluke, Beckman etc.-- possibly a used one.

    I shudder to recommend e-bay. Others here may have some recent experience with DMMs and where to buy a reasonable/good meter.

    Good Luck Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • backroad
    backroad Solar Expert Posts: 185 ✭✭
    #5
    Re: recommended multimeter?

    Please don't throw me off the board, but I've been using a sears digital multimeter for several years now with no problems and it does have a rubber "boot" around it.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #6
    Re: recommended multimeter?

    i've had good luck with the radio shack line of dmms if $40 and higher. i had one of those early dmms in the early 80s and mine blew out similarly to yours. they didn't put fuses on mine(forgot the make). some of the others mentioned are very nice if you can afford them, but most in the $40-$60 range would probably do you just fine for most applications. hint: don't buy them at lowes or home depot. sears probably would charge too much too.

    here's a few you can look at that are not high priced:
    http://www.fairradio.com/catalog.php?mode=view&categoryid=186
    i just bought one similar to the dvm890, but another brand and lower price tag.
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #7
    Re: recommended multimeter?

    I also used a Sears/Craftsman DMM for many years until I replaced it with a high-accuracy Fluke DMM. The Sears model was fine for basic stuff, and my oldest son still uses it for his projects. Can't find the manual at the moment to get the model number... :blush:

    HTH,
    Jim / crewzer
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  • System2
    System2 Posts: 6,290 admin
    #8
    Re: recommended multimeter?

    Check this out:
    http://tinyurl.com/29smys

    The reason I checked Amazon is that I recently got a credit card from them with a $30 off deal on my first Amazon purchase with it. So I could get it for $30 + shipping.
    I don't have a PC at this time, and am not sure I would have any use for the interface if I did, but...
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  • System2
    System2 Posts: 6,290 admin
    #9
    Re: recommended multimeter?

    Heh-heh. Amazon sez 199.99 marked down to 59.99.

    But http://www.multimeterwarehouse.com/mas345.htm lists the same item at 99.99 marked down to 49.99.
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #10
    Re: recommended multimeter?

    Recommend you buy one that is 'true r.m.s'. There a little more money but much better accuracy. particular for non-perfect sinewave measurements.
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  • Lefty Wright
    Lefty Wright Solar Expert Posts: 111 ✭✭
    #11
    Re: recommended multimeter?

    I am not a fan of cheap multimeters. I've had too many of them cost me time by giving me bogus readings.

    They work fine for a while and then one day they get weird.

    I bit the bullet and bought a fluke that can be calibrated. Now I just need to find a lab that can calibrate my meter every few years.
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  • System2
    System2 Posts: 6,290 admin
    #12
    Re: recommended multimeter?

    Thanks, RC, I'll keep true r.n.s. (whatever that is) in mind next time.

    Fluke may be great, but many of us amateurs can't spend that much on a meter.

    Other than that, I'm not sure that price is such a great criterion. I found the field rife with fabulous discounts of 30-60% off MSRP.
    I finally bought an SE MM2003. The site I found it on carried dozens of meters, but said this was the most popular. I don't go much by popularity when it comes to food, entertainment, clothes, etc. but I figured there might be a good reason for the popularity of a meter.
    The site had it for half the MSRP: $7.50. But they wanted $11-something for shipping. So I found it elsewhere for 4.95 + 7-something shipping. Actual shipping costs $2.83, what a rip.
    But it seems to work well enough. Though if I set it on the lowest ohm range and hold the probes together, it says 0.8.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #13
    Re: recommended multimeter?

    "True r.n.s." is actually probably "true RMS" (true root mean square)--Basically, when measuring electrical power, you have DC where Power=Volts*Current.

    But with other wave forms, you have other ways of measuring power... The typical AC meter will assume that any AC power is simply a 60 Hz sine wave center around zero volts. For single phase AC, Volts(rms)=Volts(peak)*sq.root-of-2.

    But with other wave forms (triangle waves, square waves, etc.) there is a different relationship between peak voltage and Root Mean Voltage (the voltage that actually results in power--or the Root Mean Square of the area under the curve).

    Also, if you measure an AC wave that have a DC offset--Some AC meters ignore the DC component, and others compute it into the RMS voltage...

    For the most part, the average person will do just fine with a regular meter. But if you have other needs (like accurate power measurements from Mod-square-wave inverters), then an RMS meter is needed.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Lefty Wright
    Lefty Wright Solar Expert Posts: 111 ✭✭
    #14
    Re: recommended multimeter?

    A meter that gives inaccurate voltage readings is worse than useless.

    If you can only afford an inexpensive meter buy two of them. You can then check one against the other every now and then. When one meter reads your 12V battery as 12.6V and the other says it's at 12.1V you will know that one (or both) of your meters has gone bad.

    I actually have a couple of cheap meters, one of which I keep handy next to my battery bank. I occasionally check it against my Fluke and write the correction factor on it with a pencil.

    Right now I know that I must add 0.5V to it's reading on the DC Voltage scale.

    Maybe you know someone who has a good meter you can check yours against.
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  • System2
    System2 Posts: 6,290 admin
    #15
    Re: recommended multimeter?

    The blowing out of meters by checking voltage while in the ohms mode, is very common with the cheap meters. I believe this is because those who buy the cheap ones don't really grasp how to use them. I once worked at an outlet that sold these meters and virtually every one came back with blown fuses from checking voltage while in ohms position, or the guts burned out from measuring voltage in ohms.
    The purchaser of expensive meters tended to know what they were doing, but mistakes still happened. However, many of the expensive meters are built to withstand at least some of these errors. As a professional, I've occasionally blown the fuses in my Fluke 75 (now probably 20 years old and still going strong) and once burned out a resistor when I accidentally fed it with 25,000 VDC. Thank God it was very low amperage. All these cases happened while just not watching what I was doing, but proves that given enough time, we all do it. In every case, the advanced design protected the main electronics of the meter. I was totally shocked to see so little damage after the 25,000 volt incident and hearing the arcing happening inside the meter.
    Way to go Fluke!
    Wayne
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  • rrbv
    rrbv Registered Users Posts: 16 ✭✭
    #16
    Re: recommended multimeter?

    Have had good luck with the $3 dvm's from Harbor Freight!
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