Orion XS 50A does have the possibility to control charger through node red via custom nodes to change max input and output current. However, the Orion XS 1400 does have not. It’s missing path from dbus (Settings/MaxChargeCurrent)?
I found charge current limit. Assumed this is for max output current, haven’t yet tested functionality.
Hmm, mine is in DC-DC charger mode, instead of alternator mode and it’s not in there. Maybe thats the problem…
I’m not sure of the difference. I just installed it a few days ago, but haven’t spent any time playing with it other than looking for it in NR.
I see a charger mode, which mine is set to, and a power supply mode that doesn’t have an output battery.
When in charging main battery/alternator mode I can set it, when in dc to dc from main battery to other battery it’s not. So, that seems to be conscious choice. Would become a feature request 
I wonder if the path still exists in MQTT when in power supply mode?
It has a different et of dBus paths depending on mode, so when it is providing a charge to the main battery from an alternator it is an alternator service; when it is acting as a load due too harging say a starter battery it is a DC/DC load. I do not believe the DC/DC load is modelled in NodeRed, hence your issues.