Digital meter or not...?

banjoman09 · Aug 19, 2021

Seems when I check my charging systems with a decent ($20) digital multi-meter that the voltage read out jumps around when
checking for charging..is there something better guys that will just show Volts on a steady screen? Thanks.

old · Aug 19, 2021

Common problem with the cheap digital VOMs One need an analog type VOM to get a better reading

Russ from MN · Aug 19, 2021

I keep one of the free ones from HF at the farm, and it seems to work well on our Farmall C, reads nice and steady about 7 volts.

Janicholson · Aug 19, 2021

Better is a meter that can average 3 or 4 seconds of input to arrive at a real average instead of a single sample taken in about a millisecond. The meter you have is good for the normal, good quality accurate stable source. The old vehicles and tractors we work on are electrically noisy. meaning that at at any one millisecond the actual voltage may be 50, 121, 17, or 7. Assuming it charges. The ignition system, voltage regulator points, and generator brushes all spark and arc. each moment the instantaneous voltage can be anywhere. So There are three possible solutions #1 A cheap analog VOM with a needle and scale (18 bucks or so) they rely on the needle's inertia to stay put averaging the garbage in the wires. They are not critical level accuracy. The second is a Quality analog VOM from Simpson, Triplett I have a 3030, Gardner Bender. these can cost 175+ used. They are as accurate as any disgital, but ease of use requires more thinking. The third is a 100+ dollar digital with auto ranging and certified accuracy. Fluke Drives this boat, but Triplett, and Klein, are in the game. Jim

Tony in SD · Aug 19, 2021

Probably more than you want to spend but I use either a Simpson 260 (old guy analog VOM) or a more modern Fluke 179 True RMS VOM

T.R.K. · Aug 19, 2021

Are you using it on a tractor generator? That is when I usually have trouble. The way they work is the voltage goes up until the regulator contacts open, when it drops they close and go back up until the voltage makes them open again. So up/down/up again.
A good working analog meter (with a dial) will work.

guido · Aug 19, 2021

Charging voltage is checked at the battery.
Also the meter's battery voltage maybe too low.

Minimum voltage on those cheap HF battery with a 9 volt battery is 8.4 volts.

They get goofy if the voltage drops that low,

Guido.

Geo-TH,In · Aug 19, 2021

I don't think there is a cheap digital what won't dance around.

Get a cheapie analog meter.

I use this meter, not cheap.
Advanced Battery Conductance/Electrical System Tester Midtronics MDTPBT300
Brand New
$278.99

There may be cheaper conductivity testers.

It won't dance around. Clips on to battery, measures cranking voltage, charging voltage. Uses a conductivity test to estimate battery cranking amps. The amps it measures on new batteries is the amps stamped on battery. Even more because room temp is warmer..

I carry this one in truck, don't leave home without it.

Bob M · Aug 19, 2021

For charging system diagnosis - especially on older stuff with generator/alternator and a mechanical mechanical regulator - nothing works better than an old time VOM like a Simpson 260, Triplett 630, etc.

Cheap DVMs like from HF are pretty much useless, except perhaps for checking voltage on a battery at rest. High quality DVMs (Fluke, etc) will work but are spendy.

FWIW I own a pair of Fluke DVM's - a 77 and an 87iii. But I drag out my ancient Simpson 260 for messing with old tractors.

SVcummins · Aug 20, 2021

Ive never had the problem with mine either . I have a little more fancier one but it was less than 100$

John T · Aug 20, 2021

Banjoman, Having owned and repaired such things as old generator equipped cars trucks and tractors for 50 some odd years plus todays more modern alternator systems, here is what I prefer.

My old trusty reliable Simpson 260 ANALOG VOM with its damping characteristics works great on old car truck n tractor charging troubleshooting as the meter doesn't jump around like the screen on some digital VOM's

For later model electricals/electronics I have BOTH a cheap Digital VOM as well as a Fluke Digital VOM (for its accuracy)

I think there's a time and place for all three of my meters, but for old tractors it the Simpson ANALOG hands down

John T Im sure others use and prefer different meters for their reasons, these are ONLY my opinions while others may well differ, to each their own

Leroy · Aug 20, 2021

Had a couple from HF and they did not work on anything.

banjoman09 · Aug 21, 2021

Thanks for this.....are they still available ?

Digital meter or not...?

banjoman09

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old

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Russ from MN

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Janicholson

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Tony in SD

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T.R.K.

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guido

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Geo-TH,In

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Bob M

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John T

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