I would like like monitor the current drain on a battery operated & solar charged watering system ( using an Arduino Nano ) and was wondering if the ACS724LLCTR-05AU (#4048) would allow me to have IP- and GND common, with IP+ @ +12(batt) and VCC @ +5 through regulator supplied by +12(batt)? or do the common grounds create a problem?
Thank you
Hello.
Your proposed connections indicate that the current sensor would be wired in parallel with the load which would create a short circuit across your battery! (The internal resistance between IP+ and IP- is only around 1.2mΩ.) The current sensor should be wired in series with the load you want to monitor. If you post a wiring diagram with your revised plan for connecting the sensor, I would be happy to check that for you.
- Patrick
Thank you for the quick response, I appreciate your help. So my question is, Will the LM7805 regulator sufficiently isolate the ACS724/#4048 and provide a total current value to the Nano. There will be up to 6 valves in parallel. 12V/7AH battery with 20W solar panel/charger connected.
The connections in your diagram look okay, but I recommend using a modern, more efficient switching regulator (like one of our step-down voltage regulators) instead of the ancient LM7805, especially since your application is solar/battery powered.
- Patrick
Thank you Patrick for your help with this. I’ve had a bag of miscellaneous LM78xx, LM317 regulators around for a least 30 years, so your comment about these “ancient” regulators was quite hilarious 
when I realized that I’ve had them that long:flushed:!!
I’m thinking of using the D24V22F5 in place of the 7805, your thoughts on this would be greatly appreciated.
The D24V22F5 would be fine, but if you only need to power an Arduino Nano, it is probably overkill. You might consider one of these:
- Patrick