Design or Tools for Passthrought Voltage/Current Recorder for Batteries

Thread Starter


Joined Jun 14, 2022
Okay so, currently wanting to set up a test for some rechargeable batteries, and developing a lower power mode for a system.
The goal is to connect fully charged batteries to my devices to see how much current they actually drain. I have an estimate how long they should last, but its not exact and I'd like to get a much closer estimate.

I'm looking for a pass through device with external power supply so as to not affect the current draw if possible (remember its DC not AC) and able to record ideally to a PC or have a data logger that can store roughly a few days worth of data. If there isn't really a device that does this (I've looked a bit but not sure if I'm using the right keywords or not for it, so haven't found anything to match that criteria yet) then maybe I could get some suggestions or ideas of maybe some type of Arduino project that could functionally do the same or similar thing with as little excess current usage on the battery as possible.

Links, ideas, or general discussion welcome.

Thanks in advance!

Budget Concern: Ideally under $100 total. I've got spare arduino boards and such.


Joined Jan 23, 2014
I've seen designs for using Arduinos to monitor the production of solar panels. Hall effect sensors are one option for current sensing, like the ACS712.


Joined Nov 7, 2019
Definitely a bit pricy, but I can see why too. Unfortunately I don't think this will work for my application, as it has a max operating voltage of 15V across the inputs, and I'm actually using a battery that supplies around 30V (fully charged).
Why not use a simple voltage divider. 2 identical high ohm resistors and then use the device across one of the resistors. You can then scale the voltage results by multiplying by 2.


Joined Apr 11, 2010
You have spare Arduinos but can you program them?

if you can I would add a micro-SD shield and a current sensor breakout board and build yourself one. (Note: Sparkfun has low current and current shields. Pick the one appropriate for your load resistor.)

The current draw depends on your load. You could use an actual device or a load resistor. In the latter case, you can pick one to cause any desired current draw.

You would write a sketch to sample current draw and write it to the SD card. I could then import it to my PC (and Excel) from the card. You could roughly calculate the time by noting the time you started monitoring and the programmed delay between readings. Then calculate the time of each reading in Excel.


Joined Jun 2, 2008
Maybe. Depends on what the USB port is for. Plus, you still need to do some programming on the PC to read data from USB, process it and save it to a file.
Looking at the specification of the meter it comes with software to monitor the parameter being measured and record it over time?


Joined Apr 11, 2010
Looking at the specification of the meter it comes with software to monitor the parameter being measured and record it over time?
That does sound promising. Although I’m not sure why you made that a question. And since it comes with software, the programming on the PC has been done for you.

I suggest that your next step is to learn how to use the software. The manual should explain that or provide a link to software instructions