I want to measure parasitic draw in automobiles without using my multimeter, which would otherwise require breaking a connection to connect it in series with the load. Last time I tried this I accidentally blew the big fuse in my Klein multimeter. To avoid tripping on my own ignorance again, I'd like to look into getting a clamp ammeter with a built in display, so I can measure amp draws for working on 12 volt DC automobile work.

But I'm finding confusion with too much stuff to choose from, and I also don't know what specs to look for. I need high resolution in milliamps for measuring normal and abnormal parasitic draws, and also if possible, higher amp measurement for measuring engine starting amperage.

So my question is, do clamp amps typically have the capability to do both amperage ranges with sufficient resolution in the milliamp range as well, or would I need separate clamp ammeters designed specifically for those two ranges ?

Any technical specifications advice or specific device recommendations you guys may have would be appreciated. If I had to choose only one I would want a model that's good for measuring low amperage parasitic draws for vehicles at rest, but in either case, it must have a display to avoid connecting it to my multimeter for doing the math to convert millivolts to milliamps.

The only restriction is I would like reliable quality with a solid manufacturer, but not in the expensive Fluke brand price range, since this is for light duty DIY driveway mechanic stuff. I also want to avoid generic chinese, and untrustworthy chinese branded garbage.

Any advice appreciated.

quote:

Originally posted by wrightd:

The only restriction is I would like reliable quality with a solid manufacturer, but not in the expensive Fluke brand price range, since this is for light duty DIY driveway mechanic stuff. I also want to avoid generic chinese, and untrustworthy chinese branded garbage.

Any advice appreciated.

You pay for what you get, this company is top notch, excellent support if needed. Around $250. will get you this:
https://www.aeswave.com/True-R...urr-Clamp-p9214.html


Any questions, just call them, they know what they are doing.



It will cover from milliamps up to 80A, plenty of range for what you need.

Good morning,
I do a LOT of DC and AC diagnostic work around the house and more than a dozen DC powered devices.
I use this $47.99 tool from Amazon: KAIWEETS HT206D Digital Clamp Meter T-RMS 6000, to help with parasitic draw diagnosis and resolution.
I don’t remember the exact details on the display but it has been finite enough for me. I have had it for more than 3 years, used it quite extensively, and have never had to replace the battery. I would buy again without hesitation.
I am not an electrician, this is a hobby for me.
Billy

quote:

Originally posted by p113565:
Good morning,
I do a LOT of DC and AC diagnostic work around the house and more than a dozen DC powered devices.
I use this $47.99 tool from Amazon: KAIWEETS HT206D Digital Clamp Meter T-RMS 6000, to help with parasitic draw diagnosis and resolution.

Billy

Please explain how you used this for diagnostics on automotive parasitic draw on a 12V system that can read 35 to 350+ milliamps. I don't think that meter will do it.

Like this:
Headlights, interior lights and underhood light on:


Only underhood light on:


Everything theroretically off:


I pulled every fuse and relay out and the .09 never changed. Unclamped, it read 0.00. That’s my Klein CL390 and I just did this just now. I’d been meaning to do it, but your question pushed me over the edge. Leaving the car sit for another 15 minutes, it now reads 0.00.

It will measure micro amps, but you have to hook it up in series with the probes and not go over 200 micro amps.

We are dealing with milliamps in the range of 35 to 350 or so. But anyway shouldn't that clamp be connected over both cables for parasitic draw? I understand how to test for battery load and draws, my point was that the meter mentioned above will not have the proper milliamp range to find the source of the problem.

[/QUOTE]Please explain how you used this for diagnostics on automotive parasitic draw on a 12V system that can read 35 to 350+ milliamps. I don't think that meter will do it.[/QUOTE]
I agree that this tool does not show as finite data as more expensive options but my requirement is primarily to define the presence of, not necessarily the details on the amount of draw.
My latest culprit was the sampling from the battery charging system on our, new to us, horse trailer.

quote:

Originally posted by rizzle:
We are dealing with milliamps in the range of 35 to 350 or so. But anyway shouldn't that clamp be connected over both cables for parasitic draw? I understand how to test for battery load and draws, my point was that the meter mentioned above will not have the proper milliamp range to find the source of the problem.

It’s clamped on the cable from the battery to the fuse box. Since that’s the only positive connection between the battery and the rest of the car, it will measure all draws with the engine off.

I don’t believe the clamp on DC amperage measuring capability of my meter has the resolution needed to find a small parasitic draw. I should have stated that directly. When it was measuring 0.00, the alarm system was still on. For reference, .01 amps is 10,000 microamps and 10 milliamps.

quote:

Originally posted by rizzle:
We are dealing with milliamps in the range of 35 to 350 or so. But anyway shouldn't that clamp be connected over both cables for parasitic draw? I understand how to test for battery load and draws, my point was that the meter mentioned above will not have the proper milliamp range to find the source of the problem.

That's fine, I enjoy discussions like this. In automotive the specific amount of draw will help determine what is causing it. One specific issue I remember was an extremely high milliamp draw that was cycling on a new dealership car. The protective plastic seat cover had pushed the power seat button/lever trying to move the seat tripping the breaker. Knowing the amount of draw narrows down what could cause it.

I missed this in the manual for the CL390, the minimum AC or DC current it can measure is .3 amps. So while it’s resolution is .01
amps, it can’t measure to that unless the amperage is greater than .3 amps to begin with.

Definitely not suitable for finding a parasitic draw.

The most common way to read very small amounts with a clamp on meter to make a ten turn coil and read all ten turns, dividing your readings by 10.

quote:

Originally posted by Stlhead:
The most common way to read very small amounts with a clamp on meter to make a ten turn coil and read all ten turns, dividing your readings by 10.

That works well, but you have to disconnect the circuit and run the cable through the coil. Don't have to disconnect or reconnect the cable with a clamp on milliamp meter. The new cars with the control modules reboot on power disconnect, most times you need them to stay connected for testing and watch them power down over time.

Round 2 (measurements in milliamps):

Everything just turned off except security system and underhood light:


Same as above except underhood light disconnected:


After waiting 15 minutes, security system still on:


Security system off:


So there you go, SIGforum cost me more money, but my Dad can drive his Corvette now without worrying the battery will go dead.

rizzle’s recommendation for a clamp on multimeter for checking for parasitic drains was spot on and I thank him for that! Where my Klein CL390 didn’t measure anything, my new Electronic Specialties 688 measured 373 milliamps all the way down to 7 milliamps. Seeing the difference between the alarm system on (18 milliamps) and off (7 milliamps) is neat.

Any old clamp on multimeter won’t do this. I bought the Klein CL390 to do other things, but I thought it would be good enough for this as well because I checked the specs before I bought it. I didn’t look in the manual before I bought it, so I missed the part where the had to be at least .3 amps for it to measure any current.

Glad it works for you, You can do a lot with that on fused circuits also. Make an inline fuse holder with extended wires and put male fuse terminals on the ends. Replace the fuse with the holder, using ohms law you can determine the amps and verify the system being tested. Fuel pumps and door locks, window motors, etc.

I bought the premade loops for the mini and regular fuse and they should show up today.

I always appreciate the information I get on Sig Forum.
Glad you were able to find out where the draw originated.
Billy

Earlier in the thread, I was going to suggest the Fluke 374 FC (one of my clamp meters), but that is over your stated budget and only capable of 0.1A resolution for DC current. Based on my research, not many clamp or fork meters will measure DC current in the milliamp range. Glad the Electronic Specialties 688 will do it. I may just have to get one!

This message has been edited. Last edited by: wxdave,

I've used a Uni-T UT210E for this sort of thing for several years. It can measure DC current via the clamp which isn't possible with most clamp meters/fork meters. I believe on the 2 Amp setting the resolution is 1mA. Years ago they were kind of hard to find for sale, I haven't looked recently.