AKExcalibur
Remote Solar Irrigation & IoT
Hello, I've setup a remote off-grid cabin monitoring system (using a Pi, PZEM-017 RS485 Power meter, and Shunt). I actually have it working, and using voltage to measure approximate state-of-charge works, however I'd like to log current (watt hours) and use this for a better measurement of the battery's charge and ongoing health.
The problem I've observed is that measuring with a shunt has no "sign" or directionality. The current is just the sum of current-in and current-out, such that the system being used while charging from solar power doesn't lend itself to measurement. Is there a correct way to handle this, such as using two shunts (the other to measure PV current-in to the charge controller*) and subtract? Perhaps there are better meters that actually do measure direction of current flow?
In summary, I'm interested in how other people measure power consumption and battery state, given the lack of directionality of shunt-based measurement.
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* A note on the Charge Controller: The charge controller itself is a Renogy 48v 3500w all-in-one, and seems very locked down, so I'm not bothering with trying to get data just yet. (It also uses voltage to get SoC).
The problem I've observed is that measuring with a shunt has no "sign" or directionality. The current is just the sum of current-in and current-out, such that the system being used while charging from solar power doesn't lend itself to measurement. Is there a correct way to handle this, such as using two shunts (the other to measure PV current-in to the charge controller*) and subtract? Perhaps there are better meters that actually do measure direction of current flow?
In summary, I'm interested in how other people measure power consumption and battery state, given the lack of directionality of shunt-based measurement.
---
* A note on the Charge Controller: The charge controller itself is a Renogy 48v 3500w all-in-one, and seems very locked down, so I'm not bothering with trying to get data just yet. (It also uses voltage to get SoC).