Multimeters - What Features To Look For.

[cadmus]

I have some low end unreliable multimeters. I rarely use anything other than DC and AC current and maybe the little alarm that sounds when you have a closed circuit. Although I have a general ham license I rarely had to fix anything complicated. If one was going to invest in a good Multimeter for the boat electronics and the radios what features would you all recommend making sure it had. Also please feel free to recommend brands and models.

Thanks in advance for the suggestions.

[djmarchand]

I have two meters that do everything I need to do on a boat, although I don't do any circuit board level repair.

One is a cheap, analogue multimeter from Radio Shack. It has a 0-15V scale for DC volts that is perfect for checking out charging systems and looking for excessive voltage drop. I use the AC voltage scale- 0-150V just to check for AC voltage presence. The other function I use is resistance, but a continuity function would work just as well.

Analogue meters are simpler and more reliable IMO than digital.

The other is an Ancor, clamp on DC/AC current meter. It has 0-40 and 0-200 amp scales which is perfect for everything except checking starting amperage.

David

[redsky49]

As for brands, you certainly can't go wrong with Fluke, though I am sad to note that they mostly are being manufactured offshore.

As for features, the "clamp-on" ammeter is very useful, as is the ability to add a thermister probe for temperature measurements.

Things that I have appreciated are the averaging and peak hold features, as well as an audible beep to signal the measurement has been completed - especially when you are unable to see the meter while holding the probes in place.

A long set of accessory leads and some alligator clips have also been useful.

I have also carried a very small inexpensive Radio Shack multimeter in my motorcycle tool kit that has been useful.

[SURV69]

No matter what you get, make sure the @#$@^%$@^#$ unit can be calibrated.

I have a really big, somewhat costly . . . Harbor Freight . . . multimeter.

My buddy Gary has a really big(and he said very costly), multimeter.

Another buddy Alex has a cheap $2 analog.

I have a fully charged battery...

readings(by memory so really just to give you an idea)

mine 12.1 volts
Gary 12.9 volts
Alex 12.3 volts

So I think my battery is dead, Gary thinks I'm boiling the battery and Alex thinks my battery is maybe okay.

So I put my battery on charge and after an hour or so, the charger(boat charger), goes through the routine and shuts down.

I cross a small light for a second or two and make new readings

mine 12.3 volts
Gary 13.3 volts
Alex 12.5 volts

Know your multimeter and learn how to "accurately",(forget the #@#@$$%$^$$%^#@%$ precision) calibrate it.

[SURV69]

BTW... if anyone knows how to actually calibrate these things accurately, I'd like to know....

[osirissail]

For use on a cruising boat I would strongly suggest only getting a "digital" multimeter with at least 2 digits after the decimal point. Battery voltages from full to effectively discharged (50%) is about 1/2 of a volt (0.5V). Analog meters can rarely give you a display where that can be discerned with any reasonable amount of accuracy.

Digital multimeters can be purchased from US$5 to US$15 from various stores and on-line. So there really isn't a significant price savings by going to analog meters.

However, I would suggest getting two or three of them and then keeping the "spares" in sealed zip-lock or vacuum sealed bags on your boat.

The salt air atmosphere plays havoc with the contacts and it isn't long before corrosion keeps them from working. I end up "ratcheting" the selector know back and forth trying to get a good contact and the meter to function. Sometimes, when desperate I take the case apart and use a pencil eraser to clean the selector knob sections on the circuit board. This happens whether the meter is a fancy expensive model or a $5 special.

[foggysail]

Electronic instrumentation has advanced to the point where today's run of the market inexpensive multimeter has qualities never imagined 20 or so years ago.

I purchased a meter about 5 years ago from Home Depot (Greenlee) for about $50. It more than meets my requirements. Calibration was mentioned earlier. For most applications, I doubt calibration is needed for most non laboratory type uses.

There is one feature that I do recommend! Make sure the meter has removable test leads!!!! I have seen some with the leads actually entering into the meter proper. Leads are fragile, over time they can fail. Why throw away a working meter just because it has a failed set of test probes? JMHO

[Sandero]

I recently used my multimeter to confirm the voltage reported by the link20. It was good enough for gummint work. I believe I got it from Amazon or Radio Shack... I can't recall the brand.

[westsail42]

Look for one that has an audible continuity test. I use the one on my Fluke all the time.

[Dockhead]

I have a Sinometer multimeter stencil branded by Radio Shack. It is no Fluke, but I am very pleased with it -- it has been totally reliable and is plenty accurate enough for my uses (I mess about with electricity, but am no electrical engineer, to say the least). I have checked current and voltage readings against my Victron battery monitor and other known reliable instruments and the readings correspond very closely.

It does volts AC and DC with a very large range from millivolts to 1000's of volts, with auto or manual ranging.

It does ohms, and unlike the really cheap multimeters, the accuracy is reasonable.

It will test capacitors and does AC frequency.

It has a pyrometer and does temperature, although I don't need that since I have a laser thermometer.

It is a clamp meter and measures current inductively for both AC and DC over a wide range.

And it has a buzzer for checking continuity, something which I have found remarkably useful.

It shuts itself off if you forget to switch it off (I was always killing the batts in my El-Cheapo multimeter).

It is very nicely made and comes with quality leads and a nice case.

It was Radio Shack 22-171; don't know if it is still available.

[cadmus]

In only 1 hour I got a page full of great responses. What great support, thanks. Keep um coming, i am listening.

[Cotemar]

The small Digital Multimeter from Amazon or Radio Shack are perfect for a boat.

[cadmus]

Thanks everyone. These are all good suggestions.

Let me better define "for the boat":
I plan on selling the house and living on a boat someday soon. so it would be for everything radio, electrical, everything.
Some of them measure fancy digital signals, frequencies, stuff i do not yet understand but might have to learn when forced to fix stuff i know nothing about.

I have to vent:
I went to a ham radio "hamfest" 6 years ago and somehow won a raffle for some fancy HP multimeter that was worth more than my car. I was teaching highschool physics at the time and man that would have been nice to have. I never heard the raffle number called so i missed out on it. ERG. I kick myself every time i think of it. i feel much better now. sharing helps the wounds heal. sorry for that digression.

[SURV69]

Am I the only person who's had "calibration" issue? Am I that lucky? Should I buy a lottery ticket?

Well, actually I mean . . . Are we the only three people who have had calibration issues with multimeters? Are we all that lucky? Should we go together and buy some lottery tickets?

With the variance I've denoted, a person might believe a good battery is bad, or that a bad battery is good.

[SURV69]

Sorry . . . keep in mind that precision means almost nothing if the accuracy isn't there in the first place.