A meter "veer"...

[Brian Roth]

Branching from this thread:

https://groupdiy.com/threads/dmm-recommendations.78818/
Buried in that thread I mentioned I bought a "clamp" ammeter that was affordable compared to an Amprobe (now Fluke) for me at the time.

The one I chose (brand forgotten....well over 10 years ago) would measure both AC and DC current. Worked well for a few years...then suddenly went dead. I inspected the innards....no DuraHell battery leakage (I removed the batteries when not using it). Nothing obvious when looking at all the surface mount parts, so I sadly binned it.

Wish I had a clamp meter recently while troubleshooting the reason why my ancient (1999) Passat was draining the battery overnight.

The meter that died came in handy several years ago when I was checking the DC current draw on the 5V busbar in the "DSP rack" of a Neve Capricorn....several hundred (300/400?)amps.

In the real-world for me now, I wish I have an "Amprobe" to do mundane checks like current draw on AC mains circuits....AND check DC current draw on PSU lines...or an ancient VW <g>.

Suggestions?

Bri

 

[Brian Roth]

I spent $$$$$ decades ago and bought (new) the best Tek scope I could afford...a 2215 IIRC. Workhorse that still lights up and "sees" signals.

Recently a friend bought a Rigol that I've used. MUCH smaller than my Tek and has all sorts of info on the screen.

Bummer is that it is quite sluggish when displaying anything when I decide to look at a signal (probes or patch cables). Olde Tek will display whatever instantly.

Bri....stirring up a mess here lOL.

 

[Brian Roth]

Branching from this thread:

https://groupdiy.com/threads/dmm-recommendations.78818/
Buried in that thread I mentioned I bought a "clamp" ammeter that was affordable compared to an Amprobe (now Fluke) for me at the time.

The one I chose (brand forgotten....well over 10 years ago) would measure both AC and DC current. Worked well for a few years...then suddenly went dead. I inspected the innards....no DuraHell battery leakage (I removed the batteries when not using it). Nothing obvious when looking at all the surface mount parts, so I sadly binned it.

Wish I had a clamp meter recently while troubleshooting the reason why my ancient (1999) Passat was draining the battery overnight.

The meter that died came in handy several years ago when I was checking the DC current draw on the 5V busbar in the "DSP rack" of a Neve Capricorn....several hundred (300/400?)amps.

In the real-world for me now, I wish I have an "Amprobe" to do mundane checks like current draw on AC mains circuits....AND check DC current draw on PSU lines...or an ancient VW <g>.

Suggestions?

Bri

I think I found the "cheap" clamp meter.....spent too much time looking:

https://www.newark.com/tenma/72-9485/digital-multimeter-clamp/dp/76T4531
https://www.farnell.com/datasheets/2724196.pdf
"Fool me Once, shame on you. Fool me twice, shame on me"

Specs look correct as I recall though...


Looking for better and not break the bank..

Bri

 

[cyrano]

You can buy current transformers separately and use any cheap DMM as display. Not much cheaper, but virtually indestructible.

I used to do that when I occasionally needed to measure large currents. My clamp meter only went up to 100 A...

 

[Brian Roth]

I'm stupid....how can a "current transformer' measure DC current after a tiny "starting blip"?

I can see how a tranny could measure AC current in real time....

Bri

 

[cyrano]

DC current transformers create a stable magnetic field around a conductor carrying DC current, thereby inducing a proportional voltage on the secondary side...

That's what the folder tells me

Obviously you need separate transformers for AC and DC. I hardly ever needed to measure DC, so I only had one DC measurement transformer.

 

[Brian Roth]

OK...that math makes sense.....but then I will need a separate voltage/current source for the secondary.

I also need to measure DC current once in a Blue Moon.........BUT....sometimes I want that capability at my fingertips! <g>

Bri

 

[cyrano]

You could also lust for other frequencies than 50 or 60 Hz. Some ships have 400 Hz nets. And of course, VFD for electrical motors. But that gets costly fast.

Damn. Now I talked myself into a new DMM. One that measures capacitance...

 

[Brian Roth]

Amen....that's why, early in this thread, that I warned many inexpensive DMMs are limited in frequency response...ie, 50Hz to 400 Hz.

Bri

 

[Audio1Man]

Hi Brian

Here are a few of my CURRENT SAMPLERS.

10 turn amplifiers, 1 turn & Extech AC/DC ClampOn

Duke

 

[Brian Roth]

Hello Duke...thanks for the response! I like your DIY mains "sampler" cable. I did something similar (but less elaborate) with "industrial" male and female Edison cable-mount connectors and some solid #12 THHN wire. Although my inexpensive clamp meter died, I still have my gizmo in a pocket of my Meter Bag.

I looked up that Extech.....not inexpensive. Sigh! While I have a Jones for high end tools and test gear, I have to often slap myself back to reality because I am semi retired these days. The clamp meter is a "once every year or three" for me, yet I had a bad experience with the inexpensive one I linked.

Bri

Correction....stranded THHN as I recall. I'll have to double check that; I bought individual black/white/green pieces from the "we'll cut it for you by the foot" reels at Home Despot <g> or whatever.

 

[Brian Roth]

I have to "clearly think" about my Jones for a new ammeter. I was trying to troubleshoot an oddball automotive problem (ie, battery draining after the car sat for a day or two...). My "crazy" idea was to sample the DC current draining from the battery and then start yanking fuses to try and suss which path was the culprit. I handed it over to the local guy who is the automotive electrical system expert....but he hates VW cars. He told me "take it to the local VW dealer and pray ....or junk it <g>."

So I'm junking Mom's (RIP) Passat and bought another vehicle.

Amprobe (USA made) has several clamp meters that have AC and DC ranges.

The last time I needed "high ampere" measurements (hundreds of DC amps) was 8? years ago. 99% of my Real World needs are perhaps less than 20 Amps....AC or DC. Sigh....

Bri

 

[cyrano]

Maybe you can avoid measuring the current by measuring the voltage drop across the fuses?

A problem is that modern cars might need more than an hour before going to sleep (unless you have an OBD II scanner that can send the "sleep" command).

For cases like that I love my Mooshi Meter. 2 channels, remote display on my phone and monitoring to an SD card. Unfortunately, after the successful fundraiser, no longer available.

https://moosh.im/mooshimeter/
Phantom power drains hit every brand of modern car. A lot of people never notice it, if they use it as a daily driver. VW should be simple to diagnose.

 

[Brian Roth]

Phantom battery draining is the tip of the iceberg. The electrics in the Passat are haunted. Example....sitting at idle in the driveway, the electric door locks will sometimes all cycle lock/unlock several times in a row. Dashboard indicators light up randomly... and recently always show trunk lid is open. Dome lights often won't work....then they do. Dozens of electrical ghosts even after I replaced the 5 year old battery. Randomly ignores the ignition switch when attempting to start it.

Local "electrical guru" mechanic (well respected here) can't get ANY codes into his scanner. Several "shade tree" mechanic friends all say "it's a bad ground connection somewhere". Probably true.

Sadly the car (1999) only has 60K miles on it and the body looks "factory" since Mom always kept it in her garage since she bought it new.

Assuming I can get it started again at the mechanics shop, I'll get it back to the haciends here (or have it towed) and park it .....then fiddle with it myself when the weather is warmer. Shame to send it to the junkyard.

Bri

PS....last summer a friend and I drove from here in Kansas and retrieved Mom's car after I started clearing out our family house in Okla. City. It ran like a champ at 80 MPH on the 250 mile trip on the freeways. I drove it for several months here in Salina before it went bonkers.

 

[Brian Roth]

OK....I've done a "veer on the veer"! Apologies about the VW Passat rambling. I need to find a more appropriate forum for these car problems. Any VW owners here with suggestions? Thanks.

Bri

 

[Brian Roth]

Still seeking a "reasonably priced" clamp-on solution to measure AC or DC current every once in awhile. I'm trying to narrow down my specs......

Seldom need to measure hundreds of amperes. Dozens of amps seems reasonable.



Mil spec accuracy is not required either. Just "close enough for rock and roll".

Bri

 

[[email protected]]

Take a look at the UNI-T UT210E:

https://www.amazon.com/dp/B0BBR6JRK...industrial&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw
100A max AC/DC, but will accurately read DC milliamps on 2A range. (DCA Accuracy spec is +- 2%, ACA spec is +- 3%).
TRMS AC, the manual claims response up to 400 HZ. (ACV accuracy spec is +- 1%).
Basic DCV accuracy is given as +- .7%.
My unit consistently tested more accurate than the specs when new. I haven't retested calibration after it living in my field kit for a year, but it has been reliable.

The control arrangement is a little annoying, you switch between AC and DC measurements with the blue shift button rather than a dedicated position on the main switch, but the unit is very compact.

Overall a very handy unit.

-Mac

 

[cyrano]

Phantom battery draining is the tip of the iceberg. The electrics in the Passat are haunted. Example....sitting at idle in the driveway, the electric door locks will sometimes all cycle lock/unlock several times in a row. Dashboard indicators light up randomly... and recently always show trunk lid is open. Dome lights often won't work....then they do. Dozens of electrical ghosts even after I replaced the 5 year old battery. Randomly ignores the ignition switch when attempting to start it.

Local "electrical guru" mechanic (well respected here) can't get ANY codes into his scanner. Several "shade tree" mechanic friends all say "it's a bad ground connection somewhere". Probably true.

Sadly the car (1999) only has 60K miles on it and the body looks "factory" since Mom always kept it in her garage since she bought it new.

Assuming I can get it started again at the mechanics shop, I'll get it back to the haciends here (or have it towed) and park it .....then fiddle with it myself when the weather is warmer. Shame to send it to the junkyard.

Bri

PS....last summer a friend and I drove from here in Kansas and retrieved Mom's car after I started clearing out our family house in Okla. City. It ran like a champ at 80 MPH on the 250 mile trip on the freeways. I drove it for several months here in Salina before it went bonkers.

Check the grounds in the entire car. "Haunted" cars almost always have ground problems. Start with the ground loop that connects the motor block to the chassis.

Oklahoma is one of the states that uses salt in the winter?

 

[scott2000]

The electrics in the Passat are haunted.

Maybe could try a quick subscription to Volswagen service or alldata if that's not available and screenshot/or download the wiring schematics..

I recently paid $20 for a 3 day subscription to Kia's tech pages to hunt down an electrical issue with my Son's kia and it was a success. Grabbed a bunch of other things while I was in there.

Not sure if firefox had an update but the "take a screenshot" feature when right clicking on a page is pretty nice. Maybe I never paid attention to that feature..

 

[JohnRoberts]

I spent a couple years getting all the idiot lights dark in my 27 year old car (not easy).
===
Speaking of battery drain, I typically only drive my car once a week for my personal food shopping, less than 20 miles total round trip. I discovered over time that my short trips once a week were not enough mileage to keep my battery from deteriorating.

I now keep a smart battery charger on it while parked in my carport and the car battery is now very happy.

JR