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Old 08-22-2015, 11:27 PM   #43
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Now we're getting somewhere. Looks like you send it in unless you might live nearby.

North America Service Centers

You can use an HF meter while your expensive meter is away at a spa vacation.
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Old 08-23-2015, 09:19 AM   #44
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There is one thing worth mentioning on DVM's. Count the digits. The more expensive meters have one more. All digital meters have a plus minus last digit error along with the basic calibration of the meter. It comes as part of the package with converting analog to digital.

The other issue is the quality of the packaging. HF is about as cheap as it gets. Fluke and it's competitors are better in about every way. That is why the price spread is so big. The middle of the road units vary considerably. That has me leaning toward one of the trade names just because those folks have a reputation to maintain.

Back to the digits. If you are doing basic trouble shooting it usually does not matter as reading 12.5, 12.6 or 12.7 VDC is sufficient for a system that has 12.6 VDC present. It indicates the voltage is not 9 VDC so there is no unexplained loss to find. One can also use tricks like measuring the voltage drop from a battery center post to the crimp lug or other end of the cable. That lets you measure the 0.15 VDC drop indicating a dirty connection. This is the realm where the HF freebies shine. If it get's broken in use there is no great loss.

Where the extra digit comes into play is charging systems. 12.62, 12.63 or 12.64 is fairly reliably 12.6 not 12.7 or 12.5. That can be an issue. Save the good meter for those jobs.
A quick thought on leads. Typical DMM's have an input resistance on DC of 10 Megohms so on a 20 VDC full scale they will draw 2 microamps. Current is proportional to voltage so lower voltage, lower current. At that current it would take 500 Kohm to drop one volt. Very small wire for leads to be an issue. ;-) The light plastic coated wire is fine for voltage and resistance, not so good for higher currents. OTOH corrosion and dirt become an issue at low voltages. That is why digging in with a probe tip often makes a difference. One is puncturing an oxidation layer. Using a 20 or 30 ft clip lead back to a good ground like the battery terminal sometimes also makes sense. It also lets me look at the ground connection where I am trouble shooting to see if there is an excessive drop on that side of the circuit. Lead length on DC is not usually a problem.

As I have said, I use several meters. I also occasionally check one against the other. If they do not match within reason then I look for why. It's just an easy way to avoid those gotcha's due to a bad meter. Either one can be off so I go for a third meter or a known source.

I hope this helps folks looking for a meter to use and some of the issues with using one.
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Old 08-23-2015, 11:23 AM   #45
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The other issue is the quality of the packaging. HF is about as cheap as it gets. Fluke and it's competitors are better in about every way. That is why the price spread is so big. The middle of the road units vary considerably. That has me leaning toward one of the trade names just because those folks have a reputation to maintain.
If you have any proof that packaging has any corellation to accuracy I'd love to see it.
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Old 08-23-2015, 02:23 PM   #46
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I have a collection of Multi-Meters. including a Radio Shack I got on closeout.. I very strongly suspect it is a Fluke with a radio shack paint job (Fluke accessories fit like glove) Alas that model is no longer made.

Another radio Shack with some very nice advanced features. INCLUDING the ability to download to my laptop.

A Clamp on Crafstman (Reads both A/C and D/C amps via the clamp as well as volts. Ohms and assorted other things including temp with the included prob) Oh the RS does that too)

And an assortment of Harbor Freight meters ranging from FREE to around to.. Well I forget but it is the cheaper clamp on AC only (Reads DC volts and Ohms, but only AC amps via the clamp)

Which one I use depends on the job. And how likely I am to forget it (If it's a job where I may leave it behind.. HF-FREE with coupon is clearly called for).
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Old 08-23-2015, 05:38 PM   #47
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Old 08-23-2015, 05:53 PM   #48
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I'm going to kick this off by saying I did not read every post in the thread in great detail.

I spent 20 years as both an electronics tech, and some instructor time. My sig may give away the circumstances of said years.

I have a very nice Fluke which I sent through calibration program. It's been a while, but yeah......

I also have a $39.95 radio shack unit. Experimenting with some things - they read so closely with each other that nothing I do in civilian terms will matter for that. I've developed some diagnostic circuits, and developed an add-on (piggyback) to my BMW's ECM to over ride some of BMWs temperature processes more to my liking. Radio Shack was more than sufficient.

The one feature I love about my Fluke is the auto-ranging.

I also have an old analog meter. One thing that an analog meter is awesome for is visual indications of a transient. Wiggle this or tug on that and the needle twitch is obvious. Many digital units need to sample and the number fluttering is decidedly inconclusive in some circumstances.

I apologize if my skimming over the thread resulted in my regurgitating old news here.

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Old 08-23-2015, 08:54 PM   #49
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OP here. I surely appreciate your valuable input here. I wish I had the electronic intuitiveness you have. I can handle some 120AC stuff and also some 12VDC stuff. I've done a tad bit of electrical creativeness in my life. I added LED "through the mirror" turn signal on my Honda Goldwing. I had to build those and, add resistors etc. to make the system work. It works flawless. But, I'm surely appreciative of your thoughts here.
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Old 08-24-2015, 06:48 AM   #50
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If you have any proof that packaging has any corellation to accuracy I'd love to see it.
It doesn't have a strong correlation to accuracy but it does to longevity. At least for Volts. It can be a small issue on Ohms and cause extra circuit losses in high current situations.

The bigger issue is longevity. I recently went through my meter stash changing out 9 V batteries that had aged out. All the good meters still work fine. A couple of the HF freebies either do not work or took some fiddling to get to turn on. The switches oxidize and the LCD's lose segments.

The Fluke and B&K's meant for hand held use are also a lot more drop resistant and have cases meant for hanging and working with a probe clipped into the case so the meter hand can also push one test lead on to a contact.

What I am pointing out is that there are price point benefits. Unlike some folks I do not equate price with quality but I do look at what the price difference buys me. With DMM's its the extra digit, tighter accuracy, better longevity and convenience. I use my good meters as needed but spend more time now with the HF's because they will usually do the job and I do not worry so much about having them lost, stolen or broken. Just like any other tools.
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Old 08-24-2015, 08:54 AM   #51
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If the HF meters are free, then they go to electronics recycling when they no longer work, and a coupon gets another for the price of a tool you need to replace or a pack of batteries. How many screwdrivers or batteries would someone have to buy at HF to equal the cost of a Fluke?

I brought up accuracy because that seemed to be the original argument for *not* using a cheap meter. I'd still like to see proof that the cheap/free HF meters aren't usefully accurate.
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Old 08-24-2015, 09:24 AM   #52
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That puts you in the realm of accurate enough for what. I use mine for routine trouble shooting around the house and motor home with no problem. Not so confident with charging systems and electronics I am working on. Sometimes the third and fourth place digits count and sometimes they do not. We learned that a long time ago when most meters were analog with two places read and the third interpolated (educated guess). It is fairly easy to do 3 places these days at a reasonable cost. 4 places costs a lot more.

You get the same issue with many measuring tools not just electronics.

By the same token I have seen people obsess over fourth digit accuracy where 2 places were close enough because the conditions of use caused bigger variations. So we come back to "accurate enough" for what?
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Old 08-24-2015, 10:05 AM   #53
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Being this is an RV forum, I'd say that being accurate to to 1/20th of a volt is plenty of accuracy at 12V. Third digit levels of accuracy would be necessary to see if your batteries are charged to 12.6V resting, and if your shore power is within about three volts at 120V.
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Old 08-24-2015, 01:23 PM   #54
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If I can afford it , I buy the best. Fluke is the gold standard so I bought one. I also own snap on tools as nothing compares to the quality. I like tools , especially good tools , and I have thrown away too many cheap tools. Buy it once and forget about it.
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Old 08-24-2015, 09:47 PM   #55
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Funny I missed this thread, I am also in the market for a new DMM and I am in school to be a diesel mechanic. At the school they hand out the HF multimeters to the students for the daily labs and trouble shooting, they have nicer ones if needed but they prefer the students to break the HF ones. I asked the instructor about this and he said most of the techs he worked with in the past had a nice meter and 4-5 HF ones for field work or if there was a possibility of it being broke. When we work with the ECM or data links then we use the nicer meters. My opinion is get the 'free' HF one then a nicer one with a DC/AC Clamp that does 400 amps minimum. Good luck with your decision.
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Old 08-24-2015, 10:07 PM   #56
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Being this is an RV forum, I'd say that being accurate to to 1/20th of a volt is plenty of accuracy at 12V. Third digit levels of accuracy would be necessary to see if your batteries are charged to 12.6V resting, and if your shore power is within about three volts at 120V.
One of the points is the digitization error of plus minus one. If you have 12.6 volts your meter can read 12.5, 12.6 or 12.7 and be within spec. If you have a meter that reads 12.60 measuring the same voltage you will read 12.59, 12.60 or 12.61 due to the conversion from analog to digital. Given a target of 12.6 your results will be a lot closer with the extra digit. Significant for battery state of charge. OTOH for 120 VAC anything within 10 VAC is within spec so if you are reading around 120 you are fine. It might be higher than 10 VAC as I recall it is 10% not 10 volts. ;-)

That is the gotcha with digital measurements. Getting stable accuracy is one thing, the analog to digital conversion is another. Each part has it's specified limit.
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