Quiescent Current Measurement without Current Clamp

[Steve Smith]

Hello Ashley and thank you for the post/feedback

The resister we use is here and this page also includes the data sheet.

I think you may have seen this already based on the initial post above

I have not seen any issues with accuracy when using the 0.1 ohm resister method or any failures due to typical current draw from vehicle accessories (although I have not tested to destruction)

I have used the following custom probe that will avoid the need for maths so allowing for current to be displayed live

0.1 OHM PROBE.psprobe

Custom Probe 0.1 Ohm

(1009 Bytes) Downloaded 273 times

I hope this helps, take care......Steve

[ashtray1987]

Hello Steve,

Thanks for the feedback!

I ordered this one and shunt more similar to what you would use to monitor a caravan battery setup.

I think I'll use both with a resettable fuse rated at 10A and build the whole thing into a nice housing with banana jack's so it's easier to handle.

Cheers for your excellent support with this topic, really appreciate it!

Best Regards
Ash

[Steve Smith]

The device you describe sounds like a nice "complete" unit.(Easy to handle too)

It would be great to see the finished article and the results obtained if possible?

Take care......Steve

[ashtray1987]

Hello Steve,

I sure will!

Actually I am presenting this topic this week for Mercedes-Benz USA ADST as part of a serial decoding workshop.

What I have produced is a way to get the scope to record 3 can/lin/flexray channels along with current for bus wakeup issues. Using a single trigger and the capture alarm the scope will pickup these events by itself and save them into a folder, through which we get time and date stamp, plus how long the bus was awake for each time. So with this current shunt method the scope can be left unattended for days or weeks even.

All I need now is a way to export the serial decoding table to .asc format and I will have a better tool than my Vector hardware. Also, all our workshops will have this Xentry Scope (I'm sure you're aware of this already).

Workshop will just need to build their own shunt, but an official product from Pico would make this even more interesting

Thanks for your help Steve

Cheers,
Ash

[Alexandr]

Hello.
Tell me how to open the file - 0.1 OM PROBE.psprobe?

[Martyn]

From the PicoScope 6 Automotive menu bar

Tools->CustomProbes->Import

[Alexandr]

Martyn, thanks.
One more question!
This user probe must be used with a 0.1 ohm resistor, while measuring the voltage drop across it?

[Iver]

Alex
Yes, put the Resistor in Series and measure across it. Add another channel to monitor battery voltage.

When monitoring battery current over a long period of time you can add a charger directly to the battery to maintain correct voltage.

Something like this

[ashtray1987]

Hi Steve,

As there is a lockdown in Malaysia I decided to build my current shunt.

Unfortunately I'm not able to try it on a vehicle until after the lockdown, but I'm quite satisfied with the result

Cheers
Ash

[Steve Smith]

Thank you for posting Ash, I hope all is well with you and yours.

There seems to be time to visit these projects of recent (something good coming from a bad situation)

This is neat work and thanks to the fuse we should not have to worry about heat.

Thank you again for taking the time out to feedback

Take care.....Steve