Current Ranger setup

[Aaron]

Currently I'm testing with a Keysight 34470A multimeter with a current ranger as a side by side comparison. With the current setup I have the keysight meter averages about 130uA of consumption per hour and with the current rangers I'm seeing around ~500uA per hour. The currentranger is setup to autorange.

I do want to note that the CurrentRanger seems to be powered up via the USB since there is no battery attached. Could this be the issue at hand? Please see attachment.

[Felix]

Do you mean you measure mAh's?
The current ranger gives you a current reading, not mAh's, you'd have to do more math to determine that based on what your DUT does (is it a constant load or dynamic?)
Or are you using software to determine that?
Also, I would actually be attaching the battery, which is the recommended way to use the CurrentRanger.

[Aaron]

Felix - Ultimately I'm looking to calculate mAHs and I've created a python script to do so. There is some dynamic function to some degree but the script I've created should handle that. The devices normally should consume about ~140uA but during solenoid activation (20 milliseconds) it'll consume around ~300mA.

To give you some idea of how I'm calculating mAH's of consumption I'm adding all of the current readings in a second up and then dividing by the sample rate. Then I'm averaging out the number of samples in an hour.

When the battery is attached the device seems to get quite hot from what I've noticed. Does the device know when to not charge the battery? I'm assuming my setup is correct though?

I'll connect the battery tomorrow to see if this results in some different results. I'll report back either way on what happens.

[Aaron]

Follow on post. I changed the sample rate from average to slow and the current readings now are very inline with the Keysight meter. Do I need to adjust the parameters in regards to the CurrentRanger or am I seeing some abnormal current consumption on my devices? Currently I'm sampling around 400-500 samples a second on the keysight meter but was sampling at around 1200 samples  a second on the current ranger. Now the current ranger should be in ~450 samples per second I believe.

[Felix]

Glad you sorted out the actual readings between the two.
To be accurate the sampling rates should be about the same.
Regarding the CR getting hot - depending on what the USB connection is doing, I would now strongly recommend running it with its own battery. While USB is plugged in the charger chip will charge the battery.