My European 220v system powered by the quattro 15k keeps tripping the GFCI pedestal in the USA and I was told an isolation transformer is the way to fix that. While I know how to wire it to accept 220v USA current as input some of the pedestal only offer 120v for free and I want to see if there is a way to wire the isolation transformer to accept both voltage?
Have a look at the manual for the Auto version of the Isolation Transformer. For example: https://www.victronenergy.com/upload/documents/Isolation_Transformer_4500W_Auto/108939-Isolation_transformers-pdf-en.pdf
It can auto-switch based on the input voltage.