Recommendations for a good low current clamp meter/probe

[pedrodagr8]

Are the counts in mA as well?

Looking at the accuracy of the clamp meter:
Clamp meters calls out:
Range: 0-5,000mA
Resolution: 1mA
Accuracy: +/- 2.8% +20 digits

If I had a reading of 32.6 then my accuracy would be (32.6mA*0.028)
Therefore my reading would be 32.6 +/-0.9128mA +/- 20 counts. To get the total accuracy do I add the counts does that make it 32.6 +/- 20.9128mA. That just seems like a big difference in numbers. My reading of 32.6 could be anywhere between 11.7mA and 53.5mA. That could be the difference of a car having a parasitic draw vs. not having one.

I just wanted to double check to make sure the math is correct.

The unit for the counts depend on the resolution of the range you are in. Whatever range, it's 20 counts on the end. For example, say you are measuring 1.014 volts, then your counts would be +/- 0.020V. Now if you go up a range and read 01.01V, your counts are now +/-00.20V a bigger change. I'm curious which meter you saw has an error of +/- 20 counts. Usually, that's the sign of either a bad cheap meter or a meter that is really high resolution. For example, my UT61E has a resolution of 22,000 counts and the worst counts is 10 on AC voltage. Similarly, my Brymen BM869S has a 500,000 count DCV range where they are really pushing the Analpg-Digital Converter to its limits and on that one you can see 20 or 30 count errors. That being said, the resolution is so high that there error is still very small. On the other hand, the UT210e has a much more reasonable single digit counts, as expected with it's resolution.

Sent from my LGLS992 using Tapatalk

 

[bob_the_builder]

pedrodagr8,

To answer your question, the meter with the 20 counts is the Snap-on EEDM750
https://store.snapon.com/New-Products-Low-Current-Color-Digital-Display-Clamp-Meter-P889613.aspx

I was comparing it to the Snap-on Low Amp Probe EETA308D
https://store.snapon.com/Probes-and-Adaptors-Precision-Probe-Low-Amps-P642210.aspx

The Snap-on EEDM750 lists the following specs
Range: 0-5,000mA
Resolution: 1mA
Accuracy: +/- 2.8% +20 digits

The Snap-on EETA308D lists the following specs
Range: 0-20,000mA
Resolution: 1mA
Accuracy: +/- 1.0% +5mA

I am only focusing on the DC amp measurements since I am looking for a meter to do a quick parasitic draw tests. I am not set on the Snap-on units but I was just using them as a starting point to compare them to other clamp meters. Many that were suggested in this thread.

Also many thanks to everyone's suggestions for and help on parasitic draw testing, it sounds like the most accurate way is to use a multimeter and a battery disconnect switch. (really like that method and going to try it out this weekend). I am just looking for a meter that I can use as a quick check to tell me if I am looking in the right direction or not. Using the Snap-on EEDM750 as a baseline it is described as a parasitic draw tester. I just am really trying to understand how accurate it is and if it is any more accurate then some of the really nice inexpensive testers people have suggested.

Bob

 

[pedrodagr8]

The Snap-on EEDM750 lists the following specs
Range: 0-5,000mA
Resolution: 1mA
Accuracy: +/- 2.8% +20 digits

Yeah, that is surprisingly bad. Most meters I saw were in the range of 1-2% error with single digit +/-. You can do much better for much cheaper.

As for the other one, that appears to be the accuracy of just the clamp. You have to factor in the error of the device it will be attached to as well.

For detecting parasitic draw, a shunt meter or multimeter in shunt will give you better accuracy. For msot other things (like measuring start-up currents) you CAN'T use a multimeter because it can't handle the high load. Meanwhile, a clamp meter can handle this just fine.

 

[bob_the_builder]

As a side note the ES 688 clamp meter has basically the same accuracy of the Snap on unit.
http://www.esitest.com/688.html

For msot other things (like measuring start-up currents) you CAN'T use a multimeter because it can't handle the high load. Meanwhile, a clamp meter can handle this just fine.

What range of clamp meter should I be looking for if I want to measure start-up current or alternator charging current. In addition to the units recommend in this thread I was also looking at the. Klein CL800. It was 40amp scale and a 400amp scale.

One of the tests I am interested in running is measuring how much current my battery is accepting from my alternator. I know my alternator is putting out the correct voltage but not sure current.

Bob

 

[48548]

As a side note the ES 688 clamp meter has basically the same accuracy of the Snap on unit.
http://www.esitest.com/688.html



What range of clamp meter should I be looking for if I want to measure start-up current or alternator charging current. In addition to the units recommend in this thread I was also looking at the. Klein CL800. It was 40amp scale and a 400amp scale.

One of the tests I am interested in running is measuring how much current my battery is accepting from my alternator. I know my alternator is putting out the correct voltage but not sure current.

Bob

I bought a fluke 325 to measure my alternator amp output... worked well, I think I noticed close to 200amps out on idle when I ran the batteries down.

 

[48548]

This is what i have for better or worse..

 

[1961MGA]

Since you are in Canada, you could probably get a Canadian Tire DMM that would perform this test just fine. Most Clamp meters will not have the resolution to properly read a parasitic draw.

You really need a DMM, not a clamp meter unless you are doing starters and alternators.

Don't waste your time or money with the snapon meters. I love snapon but those are not really that good. You could get a nice Fluke 88V on kijiji for the same price of what they are asking on the truck....

 

[bob_the_builder]

Since you are in Canada, you could probably get a Canadian Tire DMM that would perform this test just fine. Most Clamp meters will not have the resolution to properly read a parasitic draw.

You really need a DMM, not a clamp meter unless you are doing starters and alternators.

Don't waste your time or money with the snapon meters. I love snapon but those are not really that good. You could get a nice Fluke 88V on kijiji for the same price of what they are asking on the truck....

I already own a Klein MM700 DMM which I really like. I started looking into clamp meters since it seemed like a quick way to do a parasitic draw. Much better then disconnecting the battery. However after looking into the accuracy of these clamp meters (even the ones advertised for parasitic draw) are not accurate enough. I think I am going to look further into this battery discount switch. I am also looking a clamp meter for measuring larger current (alternator / starter)

This all started when I started to have my battery on my 07 Tahoe go dead after 3-5 days. The battery is 2-3 years old (cheap Canadian Tire battery). I used my Snap-on battery tester / system tester and the battery, starter and alternator test out fine. The battery tester only tests voltage so I am wondering if there is an issue with the current. Is the battery accepting the charge from the alternator.

I checked all the fuses using the voltage drop method posed earlier in this thread (humble mechanic) and all the voltage levels were zero. I think the best thing is to replace the battery but I wanted to do this as learning opportunity. I guess I could also use my DMM to do a parasitic draw.

 

[Mr_B]

A half decent clamp meter will be useful for see alternator amps, car consumption amps, starter draw etc.
I use a UT210E fair bit as it kept in mobile tool kit as cheap enough not care about loss/damage but good enough get usable data. Combination of clamp meter and decent dmm either inline amp test or vd chart method works, I found plenty car draw issues and general car faults with that cheap clamp meter no drama .
switch on battery post so can have dmm for inline test seems useful concept to try plus not expensive as long meter got proper protection and correct fuse fitted .
Any clamp you want use with scope is going be around 150 to 250 dollars for decent spec .

 

[pedrodagr8]

A half decent clamp meter will be useful for see alternator amps, car consumption amps, starter draw etc.
I use a UT210E fair bit as it kept in mobile tool kit as cheap enough not care about loss/damage but good enough get usable data. Combination of clamp meter and decent dmm either inline amp test or vd chart method works, I found plenty car draw issues and general car faults with that cheap clamp meter no drama .
switch on battery post so can have dmm for inline test seems useful concept to try plus not expensive as long meter got proper protection and correct fuse fitted .
Any clamp you want use with scope is going be around 150 to 250 dollars for decent spec .

Pretty much this. Each device has its usage cases, its benefits, its drawbacks.

Clamp:

• Can measure High Amperage (100s of Amps)
• DC Clamp meters cost more than AC clamp meters.
• Don't have to break the connection (especially useful for hardwired things)
• Electrically isolated (much safer)
• Lower accuracy
• Suceptible to electromagnetic interference (can be an issue when held next to motors).

Multimeter:

• Higher accuracy
• Typically (but not always) immune to stray interference (EM, RF, etc.)
• Lower range (many can read down to uA or even nA)
• Can't handle above either 10A or 20A (depending on the device) without external equipment.
• Requires a really robust safety design ($$$) when working on high energy circuits.

 

[Rickss96]

This all started when I started to have my battery on my 07 Tahoe go dead after 3-5 days. The battery is 2-3 years old (cheap Canadian Tire battery).
.

Don't want to divert the OPs question as the info on clamp meters here is very useful, but ...
Why don't you disconnect the battery every time the car has to set for a long time (overnight, parked at work for many hours) and see if your battery still dies after a few days. Then you would know if it was a battery problem or one of the electronic modules that have developed high leakage current, or even your idea of a charge current problem.

 

[bob_the_builder]

Thanks Rickss96 I will give that a try when I have a little time to let the vehicle sit, maybe over the weekend.

In the meantime I thought I would spend a little time out in the garage and see if I actual have a parasitic draw on my vehicle. So before buying a meter I thought I would borrow a friends Extech clamp meter. The model is EX730 with an accuracy of +/-2.5% +7d in the 40 amp range.

First step was test the battery, starter, and charging system using a Snap-on EECS350. Everything tested out fine.

Second step was close all the doors, latch close the hood latch with the hood open and lock the car. I then place the clamp meter around the negative battery terminal.

[/url]IMG_20170711_202626 by bob_ss_03, on Flickr[/IMG]
The meter was reading 9.7 amps. After a few minutes it dropped to around 3 amps and then continued to drop. I left it for about 2 hours when I had to do other work. When I came back it was reading around 1.0 amps.

After all the discussion on accuracy I was not sure if I could trust this value so I thought I would also hook up my meter in series and check the amp draw.

Please tell me what I did wrong. Leaving the clamp meter on the negative terminal, I removed the negative terminal from the battery. I was concerned that I was going to connect something wrong so I took two fuse holders and attached alligator clips to them and then attached my meter to the alligator clips. This allowed me to have a 7.5 amp fuse in each meter test lead to protect my meter. I thought this was a good save idea.

[/url]IMG_20170711_201817 by bob_ss_03, on Flickr[/IMG]

I put the black lead in the COM port of the meter and the red into the 10 amp spot. I set the meter to DC amps and then connected the probes to the fused leads.

[/url]IMG_20170711_201807 by bob_ss_03, on Flickr[/IMG]

With the clamp meter reading 1.0 amps, as soon as I connected the multimeter the amperage reading would increase from 1 to around 5 amps within a few seconds of having the meter connected and I would blow the 7.5 amp fuse.

I would really like to know what I am doing wrong and why I am blowing the 7.5 amp fuse. I am assuming I have the multimeter connect up wrong or by disconnected the battery cable I woke up a computer but its odd that the clamp meter did not change the entire time.

After putting the negative battery cable back onto the battery terminal post (clamp meter still connected) I unlocked the doors and left one or two open and I could see the amp draw on the clamp meter increase as I was turning things on. The amps were jumping up to 25 - 35 amps. So I think the clamp meter is good and I just did something wrong with the multimeter.

Bob

 

[Infinia]

Yer blowing 7.5A fuses because the car battery current starts at ~ 9-10 A and drops slowly. Perhaps your added fuse opened before clamp meter reads stable.
You have a clamp meter you don't trust , a car battery whose system you don't know plus having additionally introduced yet another variable E.g. A series drop ammeter with 3 fuses and leads. Not logically an ideal scenario for solving problems! Consider debugging / learn the clamp ammeter on a stable current you trust. Then use it with confidence on the real problem avoiding the series meter /drop problem.

meter resolution

If the battery dies in in 4 days or so, i'd expect to see static drain current >100's of mA

The meter was reading 9.7 amps. After a few minutes it dropped to around 3 amps and then continued to drop. I left it for about 2 hours when I had to do other work. When I came back it was reading around 1.0 amps.

Yikes this isnt normal behavior? There's your problem , a 1 amp draw will zap a fresh starting battery flat in ~48 hours!
Alternatively to using a clamp meter (re-read 'oldwizards' post.. use a big 0.10 ohm 1% resistor and a regular DMM ) this shunt reads 100mV / amp. Very accurate technique and no fuses to burn! Hint mount the resistor across a big battery disconnect switch. Flip the switch open after a few minutes to monitor the steady state currents across the resistor.

 

[Bobioz1]

You popped the 7.5 amp fuse because you pulled more than 7.5 amps. Probably bad technique. Amp clamps tend to "shift" after being on for a while or heating up. Try this, take a test drive and turn on and off everything you can think of like blower, radio, rear defrost, etc. Shut everything off then shut off the vehicle. Open the doors and trip the latches so the vehicle thinks the doors are closed. Do the same with the hood and hood switch. This is so you can get at the fuse box's without opening a door and wakeing up some modules. Now wait a half hour without disturbing it. Now keep the electrical system "alive" with booster pac, jumper cables etc. Disconnect the battery cable and put your DMM (10 amps) between the cable and battery post. Then remove the booster pac or cables and see what the meter reads. If it's above 50 millivolts (0.050 volts) you have an excessive parasitic draw. If you ever lose power to the vehicle along the way you will have to start over from the beginning. What your meter reads will dictate your next move.

 

[bob_the_builder]

I will try it again tonight. I think my problem might have been not waiting long enough after discounting the battery. I waited 2 hours after setting up the car but maybe only 5 min after disconnecting the battery.

 

[Mr_B]

the better cheap meters are good enough for general initial parasitic draw testing, I used a ut210E for years no issues seeing a fault and pinning it down.
DMM inline is best way when want be accurate and what I do via a home-made fuse breakout made from old blade fuse with soldered on leads and inline fuse .
for starter and alternator current measuring 400A will do the job & once again the better model cheap ones can do job fine .
Main thing is learning meters and what expect to see as if not use to seeing good/bad reading conditions even a fluke won't help you fully . I would check alternator and starter cables for parasitic draw as no results at fuses (normally do them first as alternator a top contender for it), aftermarket alarms and equipment good one for it too.

 

[Michael_in_DE]

You can't go wrong with Fluke. They are also easier it get parts and accessories for as well.

 

[JohnDeere1]

I bought mine for $1 out of dollar bin at my local pawn and its very nice it's an Ideal clamp meter and has served me well, paid the same for my regular Multimeter it's a GreenLee and i love them both for the price and both are rated to 600v.