Shorter voltage logging intervals

opiedog

• January 26, 2022 01:38

Pokit meter's usefulness would be greatly enhanced by offering much shorter logging intervals. For example when measuring voltage drop of a battery while cranking an engine, the battery may appear to have adequate voltage, but under high draw from a starter motor it can drop below a point that causes the ECM to reboot. This can happen in less than a second and be difficult to detect because once cranking stops, resting voltage will appear normal. Logging frequecy of 10 to 100 times a second or shorter would aid troubleshooting. Even a second or two of data would be beneficial, though the more the merrier!

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  Shane Christopherson

  • January 26, 2022 14:03

  I agree, would love it if it could go faster at least for a short time.  Original Pokit does 1 second but the Pokit Pro can go down to 500ms, that's an improvement and should do a decent job confirming low battery voltage on crank.

  You might be able to use the oscilloscope with a trigger set for falling at at given low voltage to perhaps capture a voltage drop while cranking the engine when it dropped below say 9 or 10vdc.  I'll have to experiment with that with my Pokit Pro.

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  opiedog

  • January 29, 2022 18:45

  Good idea as an interim measure. Would prefer a table of voltage readings though. Setting trigger point might involve a little guesswork but certainly doable.

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  Shane Christopherson

  • February 09, 2022 00:00
  • Edited

  Good news!  I tested the Pokit Pro in this application and it worked fantastic!  Here is a video of it and screen shot below of what you can see.  Also a screen shot of the same test using the multimeter with min/max functions on.  I'll try another using the datalog at 500 ms to see how much that captures.

  https://youtu.be/12vrlSuDsNU

  

   

  

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  Shane Christopherson

  • February 09, 2022 00:16

  Just tried using the datalogging mode and as expected 500 ms is not fast enough for this.  Same car that we know goes down to 9-10 volts during crank the datalogging only captured down to 11.35 VDC during crank. It only captured 2 data points during cranking when the voltage would be low.

  Here's a screen shot.

  

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  opiedog

  • February 12, 2022 21:49

  Awesome Shane!

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