My cheap Gardner-Bender might be dead. Turns on but does not read any values even though it’s digital. I suppose leads could be bad though. Absent an ohm meter (duh) I’ll see if I can swap them into a circuit somewhere and test continuity that way.

Can’t afford Fluke or whatever. I’ll continue to diagnose, including a new battery and leads meanwhile.

swap out the battery with a new one ?
Honestly my 40 year old Fluke is still my go to meter.

Put it in the Ohms mode and jam a paper clip or needle nose where the Leads go.

Or take one lead at a time and do this. The odds of both leads being bad ..... I am betting on the black lead being bad.

Get back to us.

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Staunton, Virginia

I don't yet have another battery for it. It uses a 9v.

Quote
Bernie
Put it in the Ohms mode and jam a paper clip or needle nose where the Leads go.

Or take one lead at a time and do this. The odds of both leads being bad ..... I am betting on the black lead being bad.

Get back to us.

Did that. Both leads OK and the display zeros out as it should.

Put it in DC volts mode to test a known-good and charged 18V drill battery. It briefly reads about 19 volts and then just shows 0 volts.

But that may just be the battery's BMS shutting down the battery if it thinks the voltmeter is a foreign entity. In a little while I may go outside and see if it'll read a car battery.

ANOTHER drill battery test is what started all this, so I suppose that might not be possible here. That battery shows 0 volts too, even though a simple test light will light up on it.

I would try an AA 1.5 volt over the 400 amp car battery.

Even an A/C wall socket will shake you loose but a D/C Car battery is not something I would do with a FAULTY meter.

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Staunton, Virginia



Edited 1 time(s). Last edit at 09/22/2021 04:29PM by Bernie.

A while ago, I picked up an Amprobe-320 Clamp Meter on the recommendation of an engineer friend when I saw a great deal on it. I believe the MSRP was ~ $300 (regularly found on sale ~ $200). It's WAY overkill for what I need but, at $125, I pulled the trigger. Amprobe is Fluke's "bargain line" of instruments.

[www.amprobe.com]

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Bernie
I would try an AA 1.5 volt over the 400 amp car battery.

Even an A/C wall socket will shake you loose but a D/C Car battery is not something I would do with a FAULTY meter.

Good point. And besides, if this thing can't read down to a few volts it's no good to me anyway.

Quote
deckeda

But that may just be the battery's BMS shutting down the battery if it thinks the voltmeter is a foreign entity. .

That was the issue. This meter can't test batteries with a BMS controlling them. I grabbed a fresh AA Duracell and it reads 1.58v just fine.

"IT'S FIXED"

Thanks all. I guess the fancy probe types will have to wait another day.

Quote
Bernie
I would try an AA 1.5 volt over the 400 amp car battery.

Even an A/C wall socket will shake you loose but a D/C Car battery is not something I would do with a FAULTY meter.

I don't really understand this statement. An AC line voltage wall socket has the potential to kill you.

A 12v DC car battery? You can grab the leads with your bare hands standing in a puddle of water, and nothing will happen.

If you're talking about high voltage EV or hybrid batteries, or the ignition coil output, that's a different story.

Quote
Cary

Quote
Bernie
I would try an AA 1.5 volt over the 400 amp car battery.

Even an A/C wall socket will shake you loose but a D/C Car battery is not something I would do with a FAULTY meter.

I don't really understand this statement. An AC line voltage wall socket has the potential to kill you.

A 12v DC car battery? You can grab the leads with your bare hands standing in a puddle of water, and nothing will happen.

If you're talking about high voltage EV or hybrid batteries, or the ignition coil output, that's a different story.

Automobile batteries can provide lots of current. I knew a guy who was installing a second battery in parallel in is his VW Bug who failed to take his wedding band off. His wrench touched ground, and the inner surface of his wedding band was momentarily molten metal. He got lucky and got to keep the finger.

I used to work on comm systems with 48 volt station battery. The 4 rectifiers in parallel could supply 800 amps continuously, and 1200 amps momentarily. The cables that ran to the batteries were as big around as your wrist. A guy I worked with accidentally touched ground with a very large screwdriver (the shaft was at least as big as your pinkie finger) that was touching -48 volts. The screwdriver exploded, and the room went white with the flash. Luckily, nobody was injured or died.

Quote
freeradical

Quote
Cary

Quote
Bernie
I would try an AA 1.5 volt over the 400 amp car battery.

Even an A/C wall socket will shake you loose but a D/C Car battery is not something I would do with a FAULTY meter.

I don't really understand this statement. An AC line voltage wall socket has the potential to kill you.

A 12v DC car battery? You can grab the leads with your bare hands standing in a puddle of water, and nothing will happen.


If you're talking about high voltage EV or hybrid batteries, or the ignition coil output, that's a different story.

Automobile batteries can provide lots of current. I knew a guy who was installing a second battery in parallel in is his VW Bug who failed to take his wedding band off. His wrench touched ground, and the inner surface of his wedding band was momentarily molten metal. He got lucky and got to keep the finger.

I used to work on comm systems with 48 volt station battery. The 4 rectifiers in parallel could supply 800 amps continuously, and 1200 amps momentarily. The cables that ran to the batteries were as big around as your wrist. A guy I worked with accidentally touched ground with a very large screwdriver (the shaft was at least as big as your pinkie finger) that was touching -48 volts. The screwdriver exploded, and the room went white with the flash. Luckily, nobody was injured or died.

Sure, if you have a dead short across the car battery, bad things happen. Using the car battery as a test load for a DVM is not in that category.

If car batteries were that dangerous, the millions installed in cars would have much more insulation (a la hybrid battery packs with multiple safety interrupts and requirements for specific gloves and equipment) installed. Most cars have batteries with both terminals exposed.

You have to work really hard to have problems with a car battery.

By the way, how about a Fluke for under $50?
Fluke DVM

Quote
Cary
You have to work really hard to have problems with a car battery.

Not really. Just hookup a test instrument with an internal short across one and see what happens. Not a problem with a known working item, but as mentioned the meter being checked on might have had a problem.

Quote
freeradical

Quote
Cary

Quote
Bernie
I would try an AA 1.5 volt over the 400 amp car battery.

Even an A/C wall socket will shake you loose but a D/C Car battery is not something I would do with a FAULTY meter.

I don't really understand this statement. An AC line voltage wall socket has the potential to kill you.

A 12v DC car battery? You can grab the leads with your bare hands standing in a puddle of water, and nothing will happen.

If you're talking about high voltage EV or hybrid batteries, or the ignition coil output, that's a different story.

Automobile batteries can provide lots of current. I knew a guy who was installing a second battery in parallel in is his VW Bug who failed to take his wedding band off. His wrench touched ground, and the inner surface of his wedding band was momentarily molten metal. He got lucky and got to keep the finger.

I used to work on comm systems with 48 volt station battery. The 4 rectifiers in parallel could supply 800 amps continuously, and 1200 amps momentarily. The cables that ran to the batteries were as big around as your wrist. A guy I worked with accidentally touched ground with a very large screwdriver (the shaft was at least as big as your pinkie finger) that was touching -48 volts. The screwdriver exploded, and the room went white with the flash. Luckily, nobody was injured or died.

I briefly fused my metal watch band between my + battery clamp and my radiator. I yanked it free, but it was stuck briefly. To this day, I have a very faint waffle-weave scar on my wrist from the intense flash heat. HOWEVER, my Casio marine digital watch kept going for another decade.

The old Sea Scout boats I worked on were ex Military, either 24v or 32 volt. 4 massive 8 volt industrial batteries, or 2 8D 12v diesel starting batteries. A thousand amp draw for a few seconds for the starter motors. Ever see a screwdriver shaft vaporize?

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The police have no duty to respond. See Castle Rock v. Gonzales, 545 U.S. 748 (2005) or Warren v. District of Columbia[1] (444 A.2d. 1, D.C. Ct. of Ap. 1981)

[www.youtube.com]



Edited 1 time(s). Last edit at 09/23/2021 01:44AM by Racer X.

Good Morning.

My Electrician humor caused quit a stir it did.

A DC shock is constant voltage.

DC electricity grabs and is harder to break free from than the 60 cycle AC that cycles from 120 volts to zero. Thus the joke of AC shaking you loose or free from the electricity.

Being retired I will admit to getting Zapped from time to time. DC is worse.

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Staunton, Virginia