I originally posted this on the victron-dev-venus Google group, but wanted to move it over to here as this may be a more appropriate place for it now. Here's a link to the original post:
Basically, I have a REDARC BCDC1240D DC-DC charger that I use to take power from the truck alternator and charge the LiFePO4 batteries in the trailer. If you're interested in reading more, I wrote it up here:
It all works well, except because the DC-DC charger isn't Victron (and Victron don't have a suitable product), it doesn't talk to the Victron system - i.e. the CCGX. This means that all the CCGX displays is a net DC figure - but I have no way of breaking that down into how much energy is coming in from the charger (e.g. PV) vs how many energy is being consumed by DC loads in the RV.
In fact, from a data perspective, the device is dumb - there's no way data / comms available from it at all. My plan is to build a small MCU-based device with an INA3221 (essentially three INA219 chips combined) to measure the current and voltage on the 3 legs of the charger - PV input, alternator input, charger output.
My question is about the best way to get this data into the Victron system. My thinking was simply to write on the relevant MQQT topics so the charger shows up as a new device. Will that work? Has anyone done this before, and specifically, Victron doesn't have an appropriate device type for a DC-DC charger so I'll have to create some topics of my own.