I have had a quick look at using a CAN bus reader, I have an ELM327, but unfortunately Iveco haven’t used the OBDII protocols and so the normal car setting will not work. I was going to back engineer it using my PicoScope (it can read CAN messages) but I haven’t found the time yet. My AFAM replacement computer gets a dedicated speed and rpm feed so I have just used that.

I have found the Arduino computers very easy to program and there are lots of example programs that you can use as a frame for other projects. I am using 4D Systems displays which again are easy to program and interface to the Arduino. It is very easy to data log any data from an Arduino onto an SD card and then read this data into excel or other application to analyse.

Below is an example of a graph I have produced showing how the charge current and voltage change as my lithium batteries reach full charge. The data was captured from my Victron BMV by an Arduino and sored onto an SD card. The data was then loaded into excel to produce the graph. (The lines are a bit wobbly as the inverter was running and the fridge was going on and off etc).

[Linked Image von preview.ibb.co]