So I'm doing a PV project with wifi enabled statistics.
I'd like to see the watts coming in and out and the battery charge level, estimated battery charge and discharge time.
I'm designing PCB to have everything neat, and to not have to connect any wires.
I chose ACS hall effect sensors instead of shunts. ACS712 5A/20A modules (or going to 758/770 for PV) and ACS758 or ACS770 50A depending on which I will be able to get my hands on. I don't believe that 2 pins of SOT8 package can carry 30A through them.
MPPT charge controller with built in inverter for PV applications. It has AC backup when battery voltage goes below 30% threshold.
The datasheet of the PV controller states the charging voltage for battery is 13.8V±0.5V. So I'm unsure if it will gradually bump the voltage up to charge the battery or just flat line it.
Here is the problem with the battery charge monitor. I'm not sure how to detect the voltage of the battery itself when it's getting charged. If the inverter charges the battery at constant 13.8V there is no "standard" voltage divider way, if I understand correctly.
Also for the watts out calculation I need to know:
- AC power coming out
- AC power coming in
- PV power coming in
and for the battery charge time
- current battery voltage level (without load and without charging)
- watts coming into the battery
- watts coming out of the battery