In my off grid house I have a hydro-electric turbine and two separate solar arrays, each producing power at between 0 and 14.7 volts; nominally 12. The amperage varies, but the while system can peak at 50A on a clear day.
These sources are brought together so as to be in parallel through a main disconnect, at which point they are also in parallel with my AC inverter/charger and battery bank; there is a load-diverter that works with the inverter/charger to manage the batteries. Each has their own disconnect and fusing as appropriate.
I want to create a pretty comprehensive metering system using resistive shunts and Yoctopuce miliVoltRx units (posting to a RPi) that can measure and record current and voltage for each power source, as well and the battery bank. This is within the capability of the devices.
My Question is: because the DC system forms "one circuit", is it even possible to directly measure the sources; shunts are usually placed on the (-) side, does that isolate them at all? What does this look like? How can I do it?
I'm writing the software for the Yocotopuces myself, so if there is calculation combined with measurement necessary, that will be possible for me top implement. But designing that is beyond my layman's reckoning.
Sorry for not having a schematic. If it's necessary to understand the problem I can sketch something up.
Thanks for any advice!
Best Answer
the yocto millivolt rx has an isolated input so there's no worries that it could mix your measurement results up. each yoctopuce will only see the voltage due to the current in the connected shunt.
for best results use a kelvin connection, connecting the youcopuce inputs doirectly to the shunts. there's no need to connect the shuts in the negative side, but if that's most convenient do it that way.