Parasitic current measurement

[Patrick0525]

Purchased a new DC current clamp tool from AliExpress for $33 including shipping. The global reviewers said 1ma DC resolution. I was skeptical and wanted to test it on my recertified 21 Lexus RX350 which has an installed FITCAMX dash cam that pulls power from the vendor supplied Y-connector via the sunroof console. The vendor said no current pull when the car’s ignition is off.

It was sleepless nights until I was able to verify that both the car’s electrical system and the dash cam do not have parasitic current draw.

Procedure:
Close all windows
Lock the car
Wrap key fob in aluminum foil
Hood is open (Unfortunately the hood release is armed)
Wait 30 minutes
Zero DC current

No melatonin tonight.
After zeroing looks like it is 22 ma.

Good night.

 

[Rand]

looks pretty good if your battery is around 400 watt hours it would take over 60 days to discharge it.

 

[Patrick0525]

looks pretty good if your battery is around 400 watt hours it would take over 60 days to discharge it.

The battery is a 585 CCA = 80 Amp hours = 960 watt hours

Clamped on the negative terminal cable. In the garage, with the driver side window down and the door unlocked the parasitic draw is 25ma.

I am happy.

 

[JWC86]

Have a link to that device?

 

[Patrick0525]

DC AC 0.1mA High Precision Clamp Meter True RMS Digital Multimeter with Current Leakage Detect Home Appliance Tools
https://a.aliexpress.com/_mKGaea

 

[Patrick0525]

There are more expensive ones. I went cheap.

UNI-T Clamp Meter UT210E Digital Ammeter Pliers Amperimetric Clamp
https://a.aliexpress.com/_mMZIN8n

 

[nutdriver]

I've always measured parasitic drain by connecting an amp meter inline on the negative side between the battery post and the negative batteries terminal connector. Then waiting until the system goes to sleep to record the parasitic drain. I'm not sure I would trust a clamp meter to accurately measure milliamp current drain.

 

[Patrick0525]

I've always measured parasitic drain by connecting an amp meter inline on the negative side between the battery post and the negative batteries terminal connector. Then waiting until the system goes to sleep to record the parasitic drain. I'm not sure I would trust a clamp meter to accurately measure milliamp current drain.

Good enough for me. DC and AC example
Posted by end-users.

 

[SubLGT]

This 2023 thread at EEVBlog has a lot of recommendations for mA capable meters.

https://www.eevblog.com/forum/testgear/good-clamp-meter-for-low-dc-currents/

The Benning CM11 clamp meter seems to be one of the best on the market, but it is around $500.

https://www.benning.de/products-us/...meter/high-precision-current-clamp-cm-11.html

 

[Patrick0525]

This 2023 thread at EEVBlog has a lot of recommendations for mA capable meters.

https://www.eevblog.com/forum/testgear/good-clamp-meter-for-low-dc-currents/

The Benning CM11 clamp meter seems to be one of the best on the market, but it is around $500.

https://www.benning.de/products-us/...meter/high-precision-current-clamp-cm-11.html

Excellent read on what is out there. I am not in the automotive trade and a real cheapskate. The clamp meter has a real nice reversible display.

 

[Patrick0525]

Winter sale $40
UT210E

https://a.aliexpress.com/_mMXbvYP

 

[Eddie]

I remember measuring a #35 size battery at ~ 1,000 watts when measured at a 5 watt drain.

 

[Patrick0525]

I remember measuring a #35 size battery at ~ 1,000 watts when measured at a 5 watt drain.

@12V that is 417 ma. That will drain ur battery overnight.

 

[bullwinkle]

There are more expensive ones. I went cheap.

UNI-T Clamp Meter UT210E Digital Ammeter Pliers Amperimetric Clamp
https://a.aliexpress.com/_mMZIN8n

That’s the one I use to check alternator output-hook it onto the alternator red wire, start the engine, put on the carbon pile & start cranking up the load. My MGM went to >100A, meter started beeping (100A is the limit), carbon pile started smoking! It’s charging (105A alternator)! I was concerned I might have a bad diode array (which would have decreased amperage output).

 

[Patrick0525]

That’s the one I use to check alternator output-hook it onto the alternator red wire, start the engine, put on the carbon pile & start cranking up the load. My MGM went to >100A, meter started beeping (100A is the limit), carbon pile started smoking! It’s charging (105A alternator)! I was concerned I might have a bad diode array (which would have decreased amperage output).

@bullwinkle Thank u for sharing. I guess clamp-only measures dc/ac current. For frequency, voltage, capacitance, resistance u need to use the the test probe. Am I correct?

 

[Patrick0525]

Update on the UT210E from the customer service representative.

“The clamp of the UT210E is specifically designed to measure AC and DC current only.”

 

[GSCJR]

I think I need to invest in one these, checking for draws the old fashioned way with a DVOM requires you to disconnect the battery; some newer model vehicles may not like that procedure. Does anyone know what the results would be using a DVOM and a battery saver simultaneously as an alternate to the clamp? Thank you for the post @Patrick0525, I'm going to look for one; the link is no longer active.

 

[Patrick0525]

I think I need to invest in one these, checking for draws the old fashioned way with a DVOM requires you to disconnect the battery; some newer model vehicles may not like that procedure. Does anyone know what the results would be using a DVOM and a battery saver simultaneously as an alternate to the clamp? Thank you for the post @Patrick0525, I'm going to look for one; the link is no longer active.

U can get the UT210E which had 1 ma resolution.
Double check that specification.

 

[SubLGT]

I think I need to invest in one these, checking for draws the old fashioned way with a DVOM requires you to disconnect the battery; ..........

There are procedures that do not require battery disconnection. Search at youtube.

 

[Patrick0525]

No more cheap electronics from China.

USPS stop shipments