Hum on Multiplus compact on charging - in Motorhome

I have a bad hum when the charger kicks in, usually at 1am. The Multiplus is below my head so is very noticeable and keeping me awake. When inverting its much quieter. So I am considering turning off the charger in the Multiplus and fitting an IP22 charger in the motorhome.

I also have the digital control panel - would this have any effect on the Multiplus settings - I dont want it to turn on the Multiplus charger

You can in programming disable the inverter internal charger