Is there any developer documentation for the app and is it possible to change which metrics are displayed without rebuilding?
Currently my OVMS uses a custom vehicle integration, but for the purposes of the app I just select the Leaf at the moment which I guess is fine.
What I'm looking for is to display the min and max cell voltages mainly, it would be a bonus if this was just a setting somewhere that I'm missing.
Short answers: no and no.
The App is Open Source, the source code is the documentation. It's partly a result of a decompilation, I've reworked many and added some new sections, but there still are some old parts that could use at least some cleanup and comments. Any help is appreciated.
The metrics displayed are fixed both by the App and by the V2 protocol (MP), which only transmits a selection of metrics by default. MP doesn't cover cell coltages, so you'll need to extend the protocol first to be able to use them.
As an alternative you can use shell commands like "bms status" or "metrics list", and process & display their output, e.g. via KustomWidget / Tasker / Automagic.
Regards,
Michael