Low amp clamp suggestions......

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  • sbreland73
    Senior Member
    • Jan 2009
    • 1076

    #31
    It may be worth noting that the Snappy probe in question has undergone four revisions as of current. See the part number EETA308D, the one for sale at this time, where "D" refers to revision number. I own a version "C" myself, but cannot attest to the accuracy being discussed here. Perhaps S.O. has worked to improve accuracy with these later versions? HTH
    S. Breland

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    • Crusty
      Senior Member
      • Dec 2007
      • 2450

      #32
      Originally posted by greasybob
      Can the Vantage pro measure amperage inline like the original Vantage can ? Don't know why anyone would want use an amp probe to measure parasistic draw. I did a little experiment last night camparing the two methods using the Verus at different settings compared to my vantage. It's too hard to zero out the low amp probe at a 500mA setting. Put the vantage inline with the negative battery cable and you can shut it off and check it again in an hour or so. Just be careful not to blow the 10 amp fuse or the glass fuse inside (been there).
      Bob.
      Don't you remember having to put a knife switch in so all the systems could be re-energized?
      A classic example is points of a relay sticking that release when you disconnect the battery. Hook up your ammeter in series and......no draw there-!!
      THAT'S why non-intrusive testing for parasitic draws is desireable. To say nothing of systems that come alive when the battery is hooked up and you have to wait for them to "go to sleep" again. Some can take 45 minutes and some over an hour to time out and sleep.

      The technique of measuring drains across a fuse using the voltage drop is a good one, but, just opening a door can excite some systems.
      A really good example of this is the VW-Passat glow plug system that would start the glow plugs just by pulling on the driver door handle. THAT one would probably peak over the 10amp fuse in most multimeters-!! LOL (been along time since I had the misfortune of figuring one of those out-LOL)

      My knife switch originally cam from an Allen Scope back in the 70's. Still use it when the time is right but non-intrusive testing is quite often the better choice of techniques.

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      • greasybob
        Senior Member
        • May 2008
        • 1590

        #33
        I can see your point about being non intrusive, I've had to open up my Vantage more times than I can remember to solder in a new fuse because it blew before the 10 amp outside fuse. My low amp probe is the first version. About 8 or 9 years old if I remember, been beat up a bit. The closest I could get it to zero out was about 25mA. It would jump about 10mA at time. A good micro low amp probe would have to fit tightly around the wire being tested and be well insulated from outside interferance ( any other wires or load sources in the area ). Maybe the later versions of the Snap On probe have gotten better, but mine is way too finicky to measure under 100mA. I Have a video showing how to hook up a vantage inline without ever disconnecting the battery. The vehcile was an 09 Impala and the Onstar was draining the battery intermittently. Forgot I even had this video. http://www.youtube.com/watch?v=hlMdE9PQpA4

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        • Crusty
          Senior Member
          • Dec 2007
          • 2450

          #34
          Originally posted by greasybob
          I can see your point about being non intrusive, I've had to open up my Vantage more times than I can remember to solder in a new fuse because it blew before the 10 amp outside fuse. My low amp probe is the first version. About 8 or 9 years old if I remember, been beat up a bit. The closest I could get it to zero out was about 25mA. It would jump about 10mA at time. A good micro low amp probe would have to fit tightly around the wire being tested and be well insulated from outside interferance ( any other wires or load sources in the area ). Maybe the later versions of the Snap On probe have gotten better, but mine is way too finicky to measure under 100mA. I Have a video showing how to hook up a vantage inline without ever disconnecting the battery. The vehcile was an 09 Impala and the Onstar was draining the battery intermittently. Forgot I even had this video. http://www.youtube.com/watch?v=hlMdE9PQpA4
          Hey Bob.
          Chuckle, LOL. I've popped a few fuses in my day too. That's another reason to uses the non-intrusive inductive probe. If the current jumps above the maximum, it'll just show "overload" without popping a fuse (at best) or ruining your meter (if the secondary internal fuse doesn't blow quickly enough)

          This is quoted from a vehicle manufacturer
          "A typical drain today actually falls into the 7-12 mA range"

          Personally, I've found 15ma to 20ma about normal. The HIGHEST factory original parasitic drain I ever found was an 86 Buick Riviera with a CRT and five computerized modules on board, showing 65ma.

          This is from the Verdict manual
          "The optional Low Amp Current Probe, provides accurate and reliable non-intrusive testing of ignition coils, fuel injectors, fuel pumps, relays, electric motors, and parasitic draw. Use to measure current from 10 mA to 40 Amps with a resolution of 1 mA."

          Page 47 of the Vantage Pro users manual states.....
          "The Reset button (Figure 5-29) returns the recorded digital gauge min/max values to zero."


          For ANY ammeter to function it has to be in series so the circuit has to be "opened" at some point somewhere. Otherwise the ammeter is in parallel and won't read the current. The configuration of a newer model Impala with the underhood fuse/relay panel right beside the battery mounted on the strut tower facilitates accessing the wires to INITIALLY hook up the meter in parallel, then open circuit the suspect circuit for the current to change direction IMMEDIATELY thru the meter without ever actually going "open circuit"
          Not all vehicles have the configuration that allows this. Some do, some don't. It also depends on which circuit(s) you're trying to access.

          As claimed by SO, if the meter can "accurately measure 10ma", (see the screen shot right from the SO tool), it HAS to be able to be zero'd to less than that.

          The best I was able to get on Monday was a live reading of 0.011. How can it then "accurately measure 10ma"??
          The min/max "reset" button at the top of the screen does NOT reset the "digital gauge min/max values to zero."
          The best I could get was -0.011 and +0.021.

          It won't zero the way it's supposed to and the way it's claimed to be capable of. As I mentioned earlier, 40 years ago, up here, we were taught to "zero the meter" as the first step in what they then called the "diagnosticians routine".

          ANY inductive clamp is picking up the magnetic field of the current flowing. I even had everything except my computers shut down in the shop, and they were over 20 feet away from the machine and the probe. No compressors, no flourescent lights, no battery chargers, etc.

          Most of the issues guys have in any of these forums result from what advertising and sales and brochures "claim" we will get for our hard earned money, versus, the actual in field capability of the equipment.
          The same goes for the SO low amps probe.

          I would VENTURE to bet that if the Ivory Tower in Illinois (or wherever the board room is) allowed the guys like Jay G the resources, they would gladly dot the i's and cross the t's for us which would then return SnapOn equipment to their previous standards of the best in the bussiness.
          Unfortunately, the board room seems more concerned with sales figures and stock values than listening to their customers.
          Attached Files

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          • Orevin
            Senior Member
            • Aug 2010
            • 1110

            #35
            A short follow-up:

            I scored a reasonably priced Fluke i80-110 low amp probe and compared it to the SO and AES probes:


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            The SO probe is worth the money, in my opinion. I don't see a big difference compared to the more expensive Fluke.
            -Kai-
            Chicago, IL

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            • Trindaddy
              Senior Member
              • Jan 2010
              • 339

              #36
              For anyone having trouble with zeroing the meter i have found a few things. First, the "auto" mode seems to do it worse.
              Next, go to bottom of scope screen and after you know what range you'll be measuring in, adjust the scale to a range as low as poss. I think at 1a it calibrates to ten thousandths of an amp which makes the single ma digit more stable.
              Also, the other day i left the clamp under the hood of a warm engine @20ma. When i returned an hour later it read 97ma!. I reset it and re-checked, still @20ma. So be careful, temp. of tool seems to have an impact on reading.
              Nice stuff Orevin!

              Neil

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