How Do I Test a DC Volt Meter?

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The difference between the three is almost 1 volt, with no two being close enough to matter.
DC voltage is usually the most accurate mode of any multimeter, so this is surprising to hear. Have you checked the internal batteries on each of the meters? The reason I ask is I've never seen much variation on DC voltage readings from HP benchtop, to Fluke handheld, to the throw-away meters from Harbor Freight that they sometimes gave away for a few bucks. But, if you have a cheap meter with a marginal power source (battery), then that might explain the widely varying readings. However, since you have 3 meters, its not likely that all 3 would have weak batteries, but I guess its not impossible either.
 
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Few years ago, I had to change the leads (probes) of my 40 years old trusty multimeter.
I also cleaned the connectors (DeOxit).

Andrew, maybe try a simple small analog (needle) voltmeter from Canadian Tire ( just a few bucks). They works well in that range.

And you'll have a 4th one to compare with the 3 others... :wave1:
 
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I have checked the line voltage many times over the years and I have never seen it vary more than a few tenths of a volt.
It probably depends on a lot of variables. I was giving you the voltages I've checked with my voltmeters over the years as an electrician as well as what the utility promises (actually, they promise very little - only a range of voltage). Here, 4 to 6 houses are served by one pole mounted transformer, and any user's large motor can create a dip in the voltage seen by the other houses on the same t-former. I should measure my house's voltage when I fire up my Unisaw to see what happens.
 
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Andrew Shadow

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DC voltage is usually the most accurate mode of any multimeter, so this is surprising to hear. Have you checked the internal batteries on each of the meters? The reason I ask is I've never seen much variation on DC voltage readings from HP benchtop, to Fluke handheld, to the throw-away meters from Harbor Freight that they sometimes gave away for a few bucks. But, if you have a cheap meter with a marginal power source (battery), then that might explain the widely varying readings. However, since you have 3 meters, its not likely that all 3 would have weak batteries, but I guess its not impossible either.
Good point. No idea when I last checked the batteries in the testers. Two are digital and I haven't seen a low battery warning but it can't hurt to check them.
 
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My experience is similar to post #42 as well; I've usually had two or all meters on hand agree with various charging systems and 0 - 10 VDC Building Automation Signals.
I've got an older Fluke 87 Process meter that will source 4 - 20 mA and when I needed a 2 - 10 VDC signal I'd use a 1/2 watt 500 ohm [actually I think the closest I could get was 512] resistor across the leads. For a while, signal generators were too expensive and cheap ones off the internet would cook. If one of your meters measures milliamps you could put it in series with a 600 ohm resistor an inline fuse do the arithmetic and see if it matches.
I remember the Simpson meter being very common, wish I would have kept mine. Used this first Fluke meter for thirty years before I dropped it through a roof hatch. :mad:
 

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I have a few multimeters, none of them Fluke class. Two from CanTire I bought 10-15 years ago have been steady and agree. Some cheapies and small that I take on the bike for emergencies, but they aren't far off the good meters at 12V range. I bought a $60 one from China since I needed one with RMS, and it is very good, my favourite now. All my decent ones agree within a tenth or two.
I also install voltmeters on every bike I've had (at least the last 8), to monitor power usage/charging. Not expensive, and cheapie ones of those can vary, yet most surprisingly accurate. A Datel or the knockoff would be the good reference.
Just sayin, check batteries and test leads, perhaps use same test leads on each to see if consistent.... all should be close.

As for the bike's charging question, I have not had to have any dealings with an ST13 alternator.... my observation is that voltage regulators should not allow more than 14.5V, almost all hover at 14-14.2 while cruising (say 3000 rpm or above). Condition of battery can affect this, maybe want to load test your battery first (free service most places unless you have a tester). What you watch for on your bike voltmeter is excessively high voltage (~15) or excessively low voltage, which could indicate a regulator issue, assuming the battery is good.

Yuasa says fully charged battery at rest is 12.9V for an AGM, 12.5 is 50%. This is after fully charged and surface charge dissipated. A typical Battery Tender maintains a battery at 13-13.2V after full charge is reached.
Hope that helps a bit.... older Yuasa chart attached.

Yuasa Battery Charge Chart.JPG
 
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Good point. No idea when I last checked the batteries in the testers. Two are digital and I haven't seen a low battery warning but it can't hurt to check them.
So how do you check a 9v battery when you don't know if your DC meters are any good..... :rofl1:

The tounge tester is only reliable to tell you if the battery is dead or has some juice. ;)
 
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Andrew Shadow

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As for the bike's charging question, I have not had to have any dealings with an ST13 alternator.... my observation is that voltage regulators should not allow more than 14.5V, almost all hover at 14-14.2 while cruising (say 3000 rpm or above). Condition of battery can affect this, maybe want to load test your battery first (free service most places unless you have a tester). What you watch for on your bike voltmeter is excessively high voltage (~15) or excessively low voltage, which could indicate a regulator issue, assuming the battery is good.

Yuasa says fully charged battery at rest is 12.9V for an AGM, 12.5 is 50%. This is after fully charged and surface charge dissipated. A typical Battery Tender maintains a battery at 13-13.2V after full charge is reached.
Hope that helps a bit.... older Yuasa chart attached.

Yuasa Battery Charge Chart.JPG
Not an ST1300.
If it was it would be easy as it does not have a computer controlled alternator.
 
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Andrew Shadow

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So how do you check a 9v battery when you don't know if your DC meters are any good..... :rofl1:

The tounge tester is only reliable to tell you if the battery is dead or has some juice. ;)
Doesn't matter, multimeters are of no use for testing batteries anyway.
I have a small battery tester, for small batteries that is.
 
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I found the small battery testers unreliable and always use a multimeter to see the actual voltage.
for small batteries like AA/AAA/C/D a no-load voltage test is often good enough, but for automotive battery testing you need to apply a load to see the real story.

the small battery testers also apply a load, what did you find unreliable about them?
 
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Andrew Shadow

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I found the small battery testers unreliable and always use a multimeter to see the actual voltage.
No load voltage test results of a battery doesn't give you much information of value other than a guess as to its condition, same as with testing a vehicle starter battery.

I have found that the battery tester that I have seems to be quite good insofar as whenever I have a battery operated device that seems to be waning in performance or a gadget that has a low battery warning come on the batteries will always test poorly with it. If I use it to test the batteries from something that is operating well the tester will indicate that the battery is good.
 
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I have a few multimeters, none of them Fluke class. Two from CanTire I bought 10-15 years ago have been steady and agree. Some cheapies and small that I take on the bike for emergencies, but they aren't far off the good meters at 12V range. I bought a $60 one from China since I needed one with RMS, and it is very good, my favourite now. All my decent ones agree within a tenth or two.
I also install voltmeters on every bike I've had (at least the last 8), to monitor power usage/charging. Not expensive, and cheapie ones of those can vary, yet most surprisingly accurate. A Datel or the knockoff would be the good reference.
Just sayin, check batteries and test leads, perhaps use same test leads on each to see if consistent.... all should be close.

As for the bike's charging question, I have not had to have any dealings with an ST13 alternator.... my observation is that voltage regulators should not allow more than 14.5V, almost all hover at 14-14.2 while cruising (say 3000 rpm or above). Condition of battery can affect this, maybe want to load test your battery first (free service most places unless you have a tester). What you watch for on your bike voltmeter is excessively high voltage (~15) or excessively low voltage, which could indicate a regulator issue, assuming the battery is good.

Yuasa says fully charged battery at rest is 12.9V for an AGM, 12.5 is 50%. This is after fully charged and surface charge dissipated. A typical Battery Tender maintains a battery at 13-13.2V after full charge is reached.
Hope that helps a bit.... older Yuasa chart attached.

Yuasa Battery Charge Chart.JPG
Issue is, how would you know what SoC battery is when testing it with unknown multimeter? Is it 75%? 85%? or 95%???

Even brand-new battery off shelf has certain age towards its useful lifespan and maximum charge it can retain won't match ideal conditions.

Under load of recharging battery and running bike's electronics, alternator output will drop from peak. It may output 14.5v with no load, but depending upon battery's SoC, it may drop to 14.1v if battery's mostly charged or 13.8v at higher loads if battery's low. One must know battery's exact condition and SoC when measuring. Even different alternators will have different peak output voltage depending upon its wear & tear condition.

It's 3-blind-mice problem.
 
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Another way to check your meters is to ask your local friends if any one might have a calibrated meter to test against.

I do load testing every time I push the stater button. If the battery is old and I keep getting sluggish starts, time for a new battery.
I am one, that when my tank is just below half full, I fill up.
Not a paranoia, just a programmed habit that prevents running on fumes and hoping that you will make it....
A new battery and piece of mind, is better and cheaper than being stuck waiting for a tow or a jump.

The best way to test your alternator is with a DC amp meter. The clamp meter is the easiest.
Check at the battery and at the alternator. The first is just charging current. The second will be total system load.
 

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You need reference device with exact and known output to test calibration.
That's a neat bit o' kit. Not that I'm in the market but I didn't see any pricing. Are they a distributor or do you call for bulk purchasing.
 
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Andrew Shadow

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A new battery and piece of mind, is better and cheaper than being stuck waiting for a tow or a jump.
Very true if the battery is suspect or indeed the problem, but I am not trying to test the battery. If the charging system is not functioning correctly or there is a parasitic drain a new battery won't correct that.
The best way to test your alternator is with a DC amp meter. The clamp meter is the easiest.
Check at the battery and at the alternator. The first is just charging current. The second will be total system load.
This is not for my ST1300. It is for a vehicle with an alternator controlled by the vehicles computer system. From what I am learning they vary the output considerably even to the point of where it can be almost nothing under certain conditions which could lead the ill informed, such as myself, to believe that the alternator is defective when it may not be. I haven't had time to see if I can find any specifications or credible diagnostic testing procedures.

It was much easier with dumb alternators when all that had to be done was ground the voltage regulator against the alternator case to test the maximum output and the regulator.
 
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